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Artifacts by baking texture (diffuse)
after baking the image texture, the result look's a bit odd/ bad. On the left side you can see the model with the baked image texture, on the right side (the selected model) with the "real" materials. Even when I zoom in, you can see strange transitions (last image).

How do I make the baked texture look like the materials from the real model and how do I solve the artifact problem?

Render: Cycles Render
Blender Version: 2.8
Thanks in advance.

The jagged lines in the bake could be caused by a few different things:

Texture Filtering
Bad UV Map
Small Texture Size

1) Cycles image textures have an option in the node for Linear, Closest, or Cubic filtering (Smart is an option if you're using OSL). Try setting this to Cubic.
2)Even if you have a large image, it may be that the UV map in this region is too small to make effective use of the image space. Try altering your UV map to fill more of the image area, if you can.
3) You might just have a really small texture size, so the lines are jagged at that point. I can see the pixels, so this is probably it. Try baking at a higher resolution
Finally, you might use KRITA or GIMP to add a Gaussian blur to the image. You could also use Blender's compositor to do this.

Thanks for the quick answer, your suggestion worked.


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How do I make an object glow?
How do I make an object glow?

I've tried everything to make it glow but it isn't. I even made a separate material and added the texture again and used a mix shader to mix the texture and glow.

nowhere in the Node configuration is an Emmision Shader, without that I am not sure how you can create a glow.

https://blender.stackexchange.com/questions/89653/how-to-make-small-objects-emit-a-ton-of-light/89677#89677 https://blender.stackexchange.com/questions/46382/how-can-i-make-a-part-of-a-texture-glow/46389#46389

apperently most of the original nodes from McPrep were useless, so i kept the original texture node and used 2 emmision ones, a mix shader and a light path to make it look like a normal glowstone block

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Stop fluid inflow without droplets
Apologies to bother with this question seeing there were a few suggestions the site tried to give but all of them seemed years old and don't seem to be working.
On blender 2.8, I've been trying to make a simple animation of water filling a cup, and when near the top the water would stop. Yet when adding keyframes of when flow is on, then off, the steady stream turns to droplets and barely fills. Is there any way to fix this?

it is possible that your domain is to small and the fluid is getting to the top or close to it and that is stopping the fluid from flowing anymore

Sorry if explained wrong, I meant like I want the inflow to be a steady stream filling the cup but it seems to only do that if I let it run all 250 frames(And then the cup overfills and into the domain space. If I try to stop the animation early at like 100 frames out of 250 the steady stream turns to droplets and barely fills the cup

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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When I look through the camera a silver wall appears
When I try to look at the camera this silver wall appears...someone can help me??

There's nothing wrong here. That "silver wall" is just the properly lit part of the scene that the camera sees. If you go to Camera view, like you have, you get to see more of the scene than is in the camera's field of vision, and thus more than will be rendered, and the area inside the rectangle is what will be rendered from that camera in that position.


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Instancing Vertices Light sources
So I'm trying to rotate a bunch of lights around a large circle using using the instancing vertices, so each lamp is on a vertex
But when I rotate the circle, the lights rotate around the "top" lamp, and ignore the others

The lights will move with the vertices along each axis, they just rotate wrong.
So I need to know if there's a way to fix it, and how to do it, cause I am stuck.

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

just use an object and make the lamp child of the object. Then instance that object (which you can make invisible afterwards). if this does not help, please provide blend file

Okay, I’ve figured it out. Once I made the instance, it wouldn’t rotate around the center.
So I went to the ‘object’ menu
‘Apply’
‘Make instances real’
And now the instances rotate around the center point.


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UV Map doesn't show
i'm still new to blender, i'm trying to uv unwrap the label for the bottle, i have mark seam and try to UV unwrap but the texture is missing i don't know why.
FYI the label is separate object from the bottle
i have check all forum relating to UV problem but could not find the same problem as mine
i'm using the blender 3

You have 2 materials, have you assigned the good material to your faces?

Select your object in object mode, press "tab", press "A" to select all the geometry, select the material you want to assign and press the "assign" button

You have Image Editor opened, open UV Editor instead:

(or switch to UV Editing tab again)

No, it is two different editors, only one of them shows UV

Type Shift-F10.  Type it again.  It will toggle between what you think of as the "image editor" and the "UV editor".  They will have different menus along the top, and different tool choices.  But they are both instances of type IMAGE_EDITOR.  So in a way, I suppose, we're both right.

Doesn't matter. I haven't got the question


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How to compress blend file for blend stack exchange?
i'm trying to upload files to blender stack exchange (BSE) to ask other question but BSE can only upload 30MB. screenshot is not so great because node shading is too big
what i have tried but none work:
save as blend compression file (not significant)
delete all irrelevant object and materials
remove modifier and applied decimate modifier to reduce vertices
append the relevant problem to new blend file and save as new
compress it to zip file

After deleting all unnecessary data in the blend file, try all 6 options in under File menu -> Clean Up and try deleting Orphan Data in the Outliner. Alternatively you can upload your files on Dropbox or Google Drive and publicly share the files.


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Initial scene in BGE
Is there a way to set the initial scene in Blender Game Engine so it always starts at the beginning, regardless of what scene you have selected in the editor?
I hate having to go up to the top, and use the drop-down to select the right scene, every time I run it.

If you save your blend while in the scene you want next time you opend the blend will start blender with that scene.

Yeah, but I'm not talking about when loading the .blend file.  Let's say I have Main & GameOver scenes, and I'm editing GameOver.  Do I have to switch back to Main every time I press P to play, or can Blender jump back to Main for me?

I guess you could write a script that does switches scene and starts the game engine.

That's a possibility.  Was hoping Blender had a built-in method.  As it is, I set a key-sensor on the P key, so once it runs I can tap P again and it'll jump to the Main scene ...which works, but feels gimmicky.

When I use an overlay scene I use this method:
The level scene adds the overlay scene as overlay.
The overlay scene adds the level scene as background.
The BGE does not add an already loaded scene. Therefore you always get both scenes regardless what scene was the first one.
Attention: this will not work when you want to use the overlay scene with another level scene.

When i say GameOver, I don't mean overlay.  That's the scene that shows up when the game ends.  I want Blender to automatically switch back to the beginning.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Cythonize a Blender script?
I made a script that turns pixels into polygons:
https://github.com/doyousketch2/PixelDraw.py
But it slows down with each new row of pixels.
After 50 or so rows, you notice it.
I'm trying to Cythonize it, but I don't know
how you'd go about running the setup script within Blender...
I get that you can use external modules this way:
sys.path.append('/usr/local/lib/python3.4/dist-packages/')

But you can't use the one-line trick:
import pyximport; pyximport.install()

because it uses external modules;  bpy for instance.
If I try to compile it outside of Blender, I run into errors.
Most likely Python version mismatch issues.
Is there an important step I'm missing?

What you are doing sounds tricky and may not work, I don't know enough about all the linking details here. Have you done much profiling on you current script? It may be there are a few tricks to optimise it as it stands (I suspect the object creation per pixel may be slow, but would need testing, you may be better off creating verts within a single mesh). The other option is to write it as a standalone script that spits out an obj file, and just import that.

Yeah, I was thinking of creating n'gons from individual verts based on color.  It would take an entire re-write of the code to produce.  I agree it would most likely be faster, as it would just put down one polygon per color.  I do like the other idea.  I did a similar script to create 3D cactii - https://scratch.mit.edu/projects/71182224 - so I guess that's always a possibility.  Was just hoping to see a speed up using Cython, 'cuz that's what it's made for.  Then I could use the same technique to speed up other scripts as well.

I suspect if it were easy to get done we would have seen it done a lot more with blender scripts, since a lot run into performance issues. Good luck anyway.

You can have a look to http://graphicall.org/1202. But I have read your .py and my guess is that most of the runtime is into bpy.ops and creating materials. So compiling your own code won't change so much the result

I suspect you're right about the runtime.  Ty for the example.  He ran setup.py right within the script window.  I guess I was expecting that you had to drop out to a commandline to do so.  It didn't occur to me that you could just run setup in there, then load the other script after everything is compiled.  It makes sense now that I see it, but at the time, it just wasn't how I expected to use Blender.  I'll play around with it later on and see if I can get somewhere with it, and if makes any difference.

To check the difference, simply comment the calls to bpy, so that only "your" code is run

Few information: if we consider an 1024x1024 image. This is around 1 million pixels. That can be done with particles and simple dupli objects. But, creating one object per pixel (even simple) is nearly undoable in a reasonable time. The fastest is to make dupli objects (build some geometries once, and create new objects from them). Each could have its own material. But here again, so many materials... if that can help http://pasteall.org/298337/python

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Why am I getting frame rates less than 2 frames per second for my animations when I have an nVidia GeForce GTX card?
I've set the nVidia card to be used by Blender in preferences and in the nVidia Control Panel. I've tried using Cycles and Evee.  The animation is of a single MB Lab character and no matter what I try, I still get less than 2 frames per second.  I'm not sure Blender is actually using the nVidia card.  Are there some other settings that need to be changed?  Thanks in advance to anyone who tries to answer my question.

You might want to state which NVidia Card.  They have been making cards for many years so there are new and not so new.  If you are using Cycles please state so.  With Cycles you must select the GPU [device].  Some old NVidia GPUs are not recognized by Blender.  Your OS and Blender can tell you the use of your GPU.

2 frames a second on an animation render is pretty good, considering even most simpler animations + keyframes render at about 1.5-3 seconds a frame are the times most home PC GPU renders get on a render.
If you're sure these are bad frame times, you could try checking if Blender is actually using the GPU to render (if you're running cycles that is):

As others have said, it also depends on what GTX card - There's a big difference between a 1080 and a 1050.
Honestly though, like I said, 2 frames per second on any animation is not bad at all.

I've downloaded MB Lab and the issue seems to be with the modifiers that the MB Lab generated meshes have on them. Disable them in view port and you will no longer lag.


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Is it possible to control the visibility of an entire collection with drivers?
I'm trying to utilize custom properties to toggle the visibility of an entire collection on or off. However, when I right click on the restriction toggle for a collection in the outliner, the options to add, paste, or edit drivers do not appear.

Is there a method to control the visibility of entire collections with drivers, such as with an addon or custom scripting? Or are collections just completely unable to interact with drivers?
Here's a blend file I setup to demonstrate what I want to accomplish; the "Visbility Controller" empty contains a custom property titled "Collection Toggle". Ideally, when Collection Toggle is set to 0, the Spheres Collection will be visible, whilst when it's set to 1, the Spheres Collection will be disabled in renders and the viewport.

I don't think you can animate this particular property, however you can design a custom update tied to your property that loops over every object of that collection and toggles their individual visibility on or off


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Convert the output of shrinkwrap modifier into a mesh
I'm a newbie to Blender, and this is the thing I'm trying to accomplish. I've got a bezier curve in 3D space and a grid. I want to show the projection of the curve onto the grid, so I use the shrinkwrap modifier on the curve to project on the grid. So far, I managed to get all this working ok.
Now I would like the projection to appear in a render of the scene, so I think I need the output of the shrinkwrap to be a mesh (correct me if I'm wrong!). How do I do this? I'm looking for a python blender api way of accomplishing this, but any hint on how to get me started would be very appreciated.
Thanks in advace.

Do you mean apply the modifier?

Thanks for your quick reply. I'm sorry, maybe I expressed myself wrong, I'm just a newbie in blender (and english is not my first language). I actually apply the modifier and I get the projection (and the geometry checks out from what I can see). BUT the think is that now I want the resulting curve (the projection onto the grid) to appear in a render. So I guess I need it to be a mesh, right? If that's the case, my question is: how to achieve this?

Please [edit] your question and clarify the text there. Some users that might be able to help you do not read comments. Add images that show what you want to do.

Curves can be converted to a mesh, in the menu select Object > Convert to > Mesh.

For the curve to appear in a render, it has to have a thickness. At its simplest, that means just giving the curve a native Bevel in its Data tab > Geometry panel. If you like, you can convert that to a mesh.


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How to delete segment on curve using Blender 2.8 Python API?
I have a bezier curve in 3D space, made of several points. I want to be able to delete the segment that goes from (let's say) point 12 to point 13, so that now my curve has a gap where
it was previously connected. With the interface this is easy: go to Edit mode, select by hand the points, hit x and select Segment, et voila!. BUT I want to be able to do this programmatically from a python script (using the blender api).
I guess the part I'm stuck with is actually selecting the points programmatically, I've been browsing the docs but as a newbie I was not able to find an answer.
I would be very grateful for all your help.
Thanks in advance!

I was having the same problem when I realised that you can use the curve operators. So, you can do something like the following:
c = bpy.data.objects["foo"]
bpy.context.view_layer.objects.active = c
bpy.ops.object.mode_set(mode='EDIT')
c.data.splines[0].bezier_points[2].select_control_point = True
bpy.ops.curve.dissolve_verts()

The curve operators also allow you to delete, rather than dissolve points.
See: Blender curve operators


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2.8 Node Names Different
So I decided to download Blender 2.8 but the Node Editor has different node names, all the Youtube videos I watch have the 2.79 names and so do my friends. Is there any way to change it? ex. material output is just called output and what i presume is diffuse bsdf is called checker.

Diffuse BSDF is still called the same, Checker is a texture node. You can always check the official documentation: https://docs.blender.org/manual/en/latest/render/shader_nodes/index.html

When I search up Diffuse BSDF nothing shows up.

Think I found the problem, turns out the texture node editor is not the node editor I was looking for and the correct one is the Shader Editor


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Z-Combine desaturates reflection Layer
I am trying to combine some layer in the compositor with Z-Combine but in the last step the reflection is loosing its color.

In the top of the first picture you can see the part of compositing that is causing the Problem.
In The lower right is the result of combining all Layers. The reflection there has still the right saturation.
In the lower left ist the final Image. After i did the last Z-Combine. The reflection is almost grey.

Here i saved the image from the viewer node to manually add the background in a third party program (paint.net). The saturation of the reflection here is ok.

Here is the complete compositing.
I rendered 4 Layers:

Objects
Shadows
reflection
alphachannel for reflection

Am i using the Z-Combine in a wrong way?
Maybe there is a better node to add the background color.
I Guess it has something to do with the alpha channel, but why is everything alright till i add the white color with the last Z-Combine?

For the background you could use the Alpha Over node.

Hi Phour, if you're not going to be combining zdepth information I'd recommend swapping those 'Z Combine' nodes with 'AlphaOver' nodes. This could fix your problem potentially

Thank you both for the respone, but sadly i get the same result with the AlphaOver node.


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Blender - Alpha is Luminance equivalent
Coming from Maya and Arnold there is a very simple selection box in the file read node (image texture equivalent) called Alpha is Luminance which allows to use the luminosity in the RGB values of a file to drive the alpha channel. Is there an equivalent function in Blender 2.8 and Cycles?

Cycles performs this conversion automatically when a color channel (yellow socket) is a connected to a float/scalar channel (grey socket). As a result, there is no need to have an option on image textures to replace the alpha channel with the merged color channels. You can simply plug the color output directly into the float channel and it will use the luminosity.

Thanks for the reply! Will look further into it, but makes sense for now!

Be warned, because of the nature of luminance, some of your values will emit beyond their occlusion!


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Blender 2.8: link Render View to a single View Layer for rendering (multiple viewlayers, multiple cameras)
I've got several Collections (created with bpy.data.collections.new()), each consists of its own Area Light and multiple Cameras.
I've got a View Layer (scene.view_layers.new()) for each of the collections (all collections are .excluded from the viewlayer except corresponding one).
I've got a CompositorNodeRLayers and several outputfile nodes for each View Layer.
I'm trying to render each View Layer from each of its Cameras.
I'm using stereo/multiview feature of blender:
    scene.render.use_multiview = True
    scene.render.views_format = 'MULTIVIEW'

and create a Render View for each camera: scene.render.views.new().
In this setup bpy.ops.render.render(write_still=True) renders each view layer from all of the cameras even those that are not linked to any of view layer's collections (producing black images and combinatorially increasing rendering time)

Questions:

Can I link a Render View (elt of scene.render.views) to a View Layer (scene.view_layers)?
Otherwise, can I link a View Layer to a Camera?
Can I tell blender to skip cameras that are not in the object tree of a view layer being rendered?

Note that I could create different scenes, but then I'd have to call render() in a for-loop as many times as many view layers I currently have, no resources being reused between calls.

1.Ask one question at a time. 2. Comments section is for comments

@Lukasz-40sth shall I edit this question anyhow or it's just a note to recall in the future?

An edit will be welcomed and this is for the future as well.


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Rigged Shape Keys on Models With Mirror Modifier?
Sorry if this is a noob question, I'm very new to 3d modelling and animation.
I modelled a humanoid character with a mirror modifier.
I want to use a shape key to realistically animate the elbow when the forearm is rotated.
I created the shape key on the left side and used the left forearm bone as the driver.
The problem is, that if I rotate the left forearm, the shape key is also applied to the right elbow, even though the right forearm bone isn't moving.
Is there a way to use a separate driver for the right side? I don't want to apply the mirror modifier, as I will need to do some additional modelling later.

Don't do shape keys until you are done modeling, shape keys do not work for if the mesh is modified after they've been they are created.

man, as far as I know you can't even apply the mirror modification, with shape keys ... what you can do is finish your model! then make the shape keys on one side and duplicate and use mirror shape keys.

That makes sense. Cheers!


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Map bpy Object to USD prim during export?
Is there any way to map a bpy Object to a USD prim in the python USDHook?
I tried by name which worked for awhile until I hit/discovered both "." and "-" bpy object names are mapped to "_" in prim names. Which means mapping back is impossible reliably.
There seems to be some hooks added with USDHook but that only provides the material mapping.
I'm aware I could just write my own exporter.


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FloatProperty Slider Pairs That Sum to 1, Dynamically Changing
This might just not be possible but I thought I'd ask. Is it possible to have two sliders min=0.0, max=1.0. Where their contents always sum to 1 but the user can still move them.
For example a slider A and slider B. When A is increased, B decreases by some linearly proportional amount.
I tried a couple different approaches, first by just setting the value in draw:
total = myPropGroup.probA + myPropGroup.probB
if total > 1.0:
   myPropGroup.probA = myPropGroup.probA / total
   myPropGroup.probB = myPropGroup.probB / total
layoutBox.prop(myPropGroup, "probA", text="Probability A", slider=True)
layoutBox.prop(myPropGroup, "probB", text="Probability B", slider=True)

Didn't even load.
I also tried using the set and update functions of the properties but caused some infinite loops.

You'll want to use an update function on your properties. a similar instance of comparing one property to another is here.

Rough example.
Honestly a single variable could be used as a property and just subtract the value from 1 for any comparison.
import bpy

def upd_left(self, context):
    if not self.my_prop_right + self.my_prop_left == 1:
        self.my_prop_right = 1 - self.my_prop_left

def upd_right(self, context):
    if not self.my_prop_right + self.my_prop_left == 1:
        self.my_prop_left = 1 - self.my_prop_right

class TEST_PG_props(bpy.types.PropertyGroup):
    my_prop_left: bpy.props.FloatProperty(
        name="my_prop_left",
        default=0,
        min=0,
        max=1,
        update=upd_left,
        )

    my_prop_right: bpy.props.FloatProperty(
        name="my_prop_right",
        default=0,
        min=0,
        max=1,
        update=upd_right,
        )

class TEST_PT_test_panel(bpy.types.Panel):
    bl_idname = "TEST_PT_test_panel"
    bl_label = "Test Panel"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Test Tab"

    def draw(self, context):
        my_props = context.scene.my_props
        layout = self.layout
        row = layout.row()
        row.prop(my_props, "my_prop_left", text="left")
        row.prop(my_props, "my_prop_right", text="right")

classes = [
    TEST_PG_props,
    TEST_PT_test_panel,
    ]

def register():
    for cls in classes:
        bpy.utils.register_class(cls)
    bpy.types.Scene.my_props = bpy.props.PointerProperty(
            type=TEST_PG_props)

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)
    del bpy.types.Scene.my_props

if __name__ == "__main__":
    register()
```

This is better than diving by the sum because the property you're editing is set exactly and won't jump around. But instead of the if to avoid infinite recursion, you can set the underlying custom prop which won't invoke update again: self["my_prop_right"] = 1 - self.my_prop_left.

@scurest thanks for the info on using self["my_prop_right"] to avoid recursion. I was unaware of that functionality and while it Likely would be a better implementation I think I will leave the answer as is for clarity of avoiding recursion. Hopefuly anyone that finds this post in the future will read your comment and make their own decision on best implementation for their needs.


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Inverse Kinematics on *not* chained Bones
Is it possible to add IK on an Armature, that has partly no chained Bones, as you can see with the leg in the reference? If you go from down the foot, all the way to the upper leg, it is a chain of child parent relationships, as it is more intuitive for me to animate them from a horizontal perspective.
However, I don't know how to add IK for something like this. I've tried to extrude a Bone from the Foot naming it "LegControl" and I've also created a Bone that is on the same height as the Knee, naming it "KneeIK". Then, I've added the IK constraint to the FootBone and set it like this:
Target: Armature
Bone: KneeIK
Pole Target: Armature
Bone: LegControl
It produces unwanted results. Is there a way to use IK here, or is it only possible for when bones are chained together?

In my example Hips, top, mid and bot bones are yours original bones, in a parent-child relationship as FK chain.
I added top Ik, mid IK, bot IK, thigh and shin bones.

Thigh is child of hips, top IK is child of thigh, mid IK is child of shin, bot IK is child of Root bone (nothing in my example).
Shin has an IK constraint, targeting bot IK, lenght of 2, so bot IK is the bone to use when animating in IK.
Top, mid and bot have a copy transform constraint targeting their respective siblings.
I also added a custom property to drive the Influence of all the 3 Copy Transform constraints, so to act as FK/IK Slider.
When the animation is done, you can select Top, Mid and bot, go to pose menu > Animation > Bake action (visual keying, delete constraints, overwrite current), so to have the animation acting completely on the FK chain, free from any constraint.

it works, thank you very much :)


text:
Moving parallel
How to make the bones move so that they dont go into the x axis, while I'm moving the foot IK Bone. To explain it better, the picture shows, how I dont want to have it, because the upper bone off the leg as well as the knee are going in unrealistic directions and I want it to be only in one way so I can create a walk animation. Can somebody help me?

is it not working with a pole target? also, you need to bend the knee a bit in Edit mode

no, without a pole target

So try with a pole target

It didnt work out unfortunately

Could you please share your file, at least the armature?

how to implement a file here in comments?

oh nvm, I fixed the problem

If you fixed the problem then please add an answer below so other people can learn from your solution.

I forgot some things like remove parent from  the Armature of the IK Bone and I forgot to extend the chain lenght, therefore some strange stuff happened from time to time.


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Why aren't the Vertices connected?
Hello Blender Community,
I have a problem here with my mesh, because I must have accidentally done something wrong. The vertices somehow doubled or tripled themselves in place and they aren't connected anymore as there where supposed to be earlier. My intention is to lift the vertices up to form some kind of "mountains" as seen in the picture, but as shocased here the vertices act like they were independant to each other which wasn't the case. The only thing I know for now is that I've applied a Modifier wrong after experimenting for a bit, yet I don't know which of them caused it. Is it possible to reverse it?

You can remove the duplicated verts by select all, then press alt+m and choose By Distance.

thank you, it worked.


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How to keep dense particles at the center of emitter in blender 2.8?
I'm trying to make my emitter space look dense with the particles while emitting the particles. I'd done a setting which gave me the desired result but it was a hidden trial, now i'm trying to search it out for 4 days but not getting the setting exactly. I have added two pictures showing differences at center
Please try to help me if anyone could.   Thanks.
High density particles at center.

Low density particles at center or no my emiter

I'm not sure I actually understand what you're asking but: you can have two particle systems. One with a big particle lifetime, the other with a shorter one, and lesser emission speed.

a picture of what you have so far and the settings would make it easier to see where you need help.

Thank you @Kiskit and for acknowledging my ques. i'm trying to make it more clear by adding some of pictures.

So as stated in a comment, you can have two particle systems.
One (in green here) is the "outer" system. The other one (in red) the "inner" system.
By giving different lifetimes and initial velocities to your systems, you can probably approach your desired result.

Green is long lived with high velocity

Red/inner is short lived and with low velocity

Thankyou so much, this could be work as second way to make it. @Kiskit

Yes i got the final way to it by turn one one setting in particle mode, all i want to make it more glowing at the center by using single particle system.[![Dead tab[![Dead tab disable result.

Should be enabled

If anything, try "Unborn". It should render particles before they are born, which is what happens if they're emitted from the center. "Dead" renders particles once they're dead, so if they originate from the center, they will accumulate at the periphery.
In any case, this is not the purpose of that option, but in the end, only the result counts.


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Normals doesn't show up
I have a problem on Blender:
I select an object, I switch in edit mode, and then in the "viewport overlays" menu, I click on display normals (at the bottom of the menu) but nothing appears.
The other thing is that when I want to display other types of normals ("vertex normals" and "split normals") it works.
Can someone tell me if there is something that could explain this issue ?
Thanks

maybe face normals are fliped inside

Even if I flip them, still the same situation, I can't see them, even if I zoom et re-scale the mesh.

so it could be a bug. i dont have this problem in 2.91. somerimes changing workspaces fix this not showing up stuff


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Adding Textures to Glove Rig
So I have made an animation for a pair of gloves, more specifically https://gamebanana.com/models/4308
The problem that I have with this is that I do not know how to apply the textures to the gloves themselves, as whenever I try to select the gloves mesh I always end up selecting the rig, and not the gloves. I had tried hiding the rig but could not select the mesh. I went into the shading tab and there was no option to create a new material for the mesh. If any could help out, that would be appreciated. Also sorry if this post might be a little, "nooby(?)" I've never posted on here before and am still a beginner. Thank you.

Does this help ? https://blender.stackexchange.com/questions/44417/blender-wont-select-the-object-i-want-to-select

The selection of the mesh is disabled, you need to enable it first. It's a 2.79 blend file and for some reason, the materials are not shown correctly in Blender 2.8+. But you can recreate them:

Add the Shading workspace: [+] → Sculpting → Shading
Click the Filter icon, and select the first 5 Restriction Toggles. This includes Selection, the arrow icon.
The mesh is parented to the armature. Expand it and look for CSGOMotogloves. Activate Selection (arrow icon). Now you can select the mesh. Select it.
Materials exist already. Select one to recreate
Check Use Nodes in the shading editor
Add the Image Texture nodes and the Normal Map node. Select the images for the Image Texture nodes. Don't forget to set Color Space to Non-Color for the normal map image.

Repeat steps 4 to 6 for the remaining 2 materials. That's it :-)

Thank you I appreciate it thank you for responding!


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Render an object with a freestyle outline, ignoring objects made invisible by holdout
I have a view layer. A few collections have holdout enabled, as I wish to mask out the area they occupy. However, freestyle outlines sections that shouldn't be visible
Essentially, if I have the setup with the two cubes, with one with holdout enabled,

How do I prevent the masked segments from having lines?

This is a known limitation: freestyle not influenced by holdout collections.
If you set Holdout as shader material to an object, it works:

Except, one line is missing. This is because majority of the line is hidden. If majority was in front, the entire line would be visible (well, unless the line is cut by another line):

This is also a limitation of Freestyle: Freestyle with occluded objects - freestyle lines bleed into hidden regions. The solution is increasing the geometry (effectively dividing the line into many segments).

If there's too many objects to go for that, you can create a new View Layer, in old View layer disable the holdout collection by clicking on the check-mark icon , while in new layer make the base collection (the one that should be visible), as the holdout layer. This way on the 2nd view layer what's visible is what you want to cut from the first view layer, which you set in a compositor like this:


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Merge faces to use the solidify modifier and UV-map
I have some issues with welding faces together so I can use a solidify modifier properly and so I can UV-map it.
In the picture you see a cardboard folded model that is exported from a specific software. It is however loaded as seperate faces. Is there an easy and quick way to join these together? Some searching on the internet gives me nothing, maybe I use the wrong key-words...
Thanks a lot!

The illustration appears to have thickness.. is that the way it was exported?

Hi! No, those are folds of the cardboard you can see, everything is flat and has no thickness! :) If you would unfold it, it's a flat sheet.

Does M > Merge > By Distance with a tiny threshold weld the right verts together, or does it catch the wrong ones first?


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After you create some subtitles for a video in Blender, would it be possible to extract those subtitles in an SRT file?
After you made a video with subtitles on blender, would it be possible to extract those subtitles in a separate SRT so for example if you want to upload the video on Youtube instead of having the subtitles embedded in the video, you could have them on the Youtube window. In order, to avoid creating again the subtitles manually on Youtube itself, an extracted SRT file from Blender would be very handy. Do you think there is such possibility? Thanks in advance

You can export the subtitles here:

oh so simple.. nice thank you very much!!


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Mantaflow. Bake Mesh does nothing
I've been trying to find an answer online but it seems like the problem only happens to me :) The fluid simulation works well up until i try to bake mesh. This never results in any mesh, it takes time to bake but nothing gets added. The only thing that changes is that the bounding box automatically changes size to surround the particles as they move. I hope someone know what I've done wrong. / Alex

What do you mean "Bake Mesh"? Baked can be a cache, meshing has just a checkbox and is happening in realtime. What version of Blender you use?

Hello, could you add a few screenshots of your interface and how you setup your scene ?

No mesh just bounding box.
Isn't that because you have set under
Object Properties > Viewport Display > Display as > Bounds?

BTW - What happened to me (when I tried to confirm your issue) is that mesh was generated just around particles. In that case - Save your file first.
Under 2.92 if you change Resolution, Simulation method or probably any parametr which restarts cache should solve it as well.
In 2.83 LTS it was't even possible run simulation without saving a file.

This did the trick! I thought is was supposed to be bounds to not block the simulation. Thank you :)

Please consider mark answer as accepted so others can see it from main list and also to stop system pocking question in periods as unsolved. Thank you keep this site organised. https://blender.stackexchange.com/tour


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Mesh not following bones correctly
I have a problem with weight painting. This is what happens, the mesh follows the bones just partly. I have really tried to paint the mesh thoroughly from all angles. It looks like it's somehow attached to something else and being pulled apart. Thank you! / Alex

Related: https://blender.stackexchange.com/questions/174390/besides-weight-what-determines-how-much-a-vertex-group-is-affected-by-bones/174393#174393


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Where is Point Cloud?
Just downloaded version 2.92 for Mac. I am unable to find the Point Cloud option in the Add menu. Am I missing something?

Ben you mention you've seen videos where p.c. exists in the add menu.  Perhaps you could stop the video at that point, take a screen print, and include it in your question?  They say a picture is worth a thousand words.

Go to Edit-> Preferences -> Interface and check Developer Extras
This will create new tab in left column called Experimental.
In that tab you need to check New Point Cloud Type.

I can confirm this, however, this seems to be only in 2.93 up and 2.92 daily releases. 2.92 Stable does not have that menu entry.

confirm for 3.0.0 alpha

I have Developer Extras enabled and when I look at the Experimental tab, all I have is a Debugging section.  No "New Point Cloud Type".  2.93 (.3 and .5)

Pointcloud is not a generic object type in the add section.
It exist in the geometry node editor section as "Point Distribute".

Thanks for the response. I've seen several videos where people add Point Cloud from the Add menu. In the videos, it shows up right between "Text" and "Volume". Except not when I try it.


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move instanced objects relative to empty
I'm trying to move [instanced] objects up when I move an empty beneath them. Picture a 10 x 10 array of spheres. I want it to look like something is moving below them pushing them up as it moves. I don't want to deform the spheres, just move them. I did this in Modo way back when, but want to try it in blender. Am I missing something obvious? ideas? Thanks!

Here is a way to do it:

Create a large plane, subdivide it, create a sphere, create a small plane that you put at the same location as your sphere, subdivide this small plane, select all its vertices and create a vertex group:

Give your small plane a Shrinkwrap modifier / Wrap Method > Project with the large plane as Target. Give your sphere a Copy Location constraint, with the small plane as Target and in Vertex Group select the vertex group you've created, enable the Z axis only.
Create 2 empties, one under the large plane, the other one above, parent the bottom empty to the top empty, give your large plane a Warp modifier, choose the 2 empties in Object From and Object To, play with the Strength and Radius values, it will warp the plane surface:

Select the sphere and the small plane, press AltD to duplicate along the X axis, press ShiftR to repeat the duplication. Do the same on the Y axis. Make the planes invisible, move the top empty to deform the plane and the spheres should follow:

That will do just what I need. Thank you!!

Sorry I've forgotten some details in my text (about he Copy Location), but you must have guessed  ;)

Thanks. I was able to "interpolate" what I needed :). And got the results I was after. I am curious, though, about the advantage of the small subdivided plane. Why not just subdivide the large plane and instance the sphere to its' vertices?

it really depends on what you want, if you instance to the vertices, the instanced object won't be constrained on the Z axis, there may be a simpler solution than mine though

Hello 'boots :). I seems you can simply use a cast modifier for this: https://blender.stackexchange.com/a/211242/78972 (that guy is good)

oh ok, maybe add the link under his question

You can also get this effect by using a cast modifier. Create a plane subdivide it.  Then in the object properties for it, set instancing to vertices and add a cast modifier. Then create whatever you want to be moving up and down. Then set the relations in its object properties to be the plane you previously made. This should instance the rectangle to all the verts on the subdivided plane.
Now create an empty, and in the cast modifier settings you added to the line, set the object to be the empty. Make sure to clamp it to the Z axis as well in the modifier settings. Mess with the scale and radius settings until you get the effect you want.


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Assigning a pre made, rigged model to a Mixamo/collada data
I cannot figure out how to assign my model, who is rigged with individual bones, to a Mixmo, rigged model.

Have you tried uploading your model directly to mixamo?

I have, that plum color actually is my model. It was before coloring though, and for some reason, the shoulders droop down. I only need walking for one or two scenes


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Assigning my rigged model to a Mixamo skelton
I was curious to know if there is a way to go about asiging a character I've made to an existing mixamo skeleton. My own model is in fact rigged, but I wasn't sure if I could temporarily assign him to the skeleton for a walking animation.

Create a copy of your rigged character, go to the first frame (or a rest pose frame, if it does exist), use your rig to copy the pose of the Mixamo rig as close as possible, then go to the modifiers and apply the armature modifier.
Not necessary, but if you want to stay clean at this point you can delete the rig and all vertex groups.
Select the character, shift select the Mixamo rig and press Ctrl P (Automatic weights).
Then you can turn on and off the visibility of the two versions of your character.

Would you happen to have more info on that?? I'm having a really hard time trying to get it done. @josh sanfelici


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How to make a single character out of many parts?
I have created a low poly model that I'm attempting to rig. Using rigify, I notice certain aspects of the model don't move, namely the legs. I believe this is because the joints, namely the torso connecting to the legs, is not fully connected by  a legit joint. I've seen that rigify works much better on solid models. Is there a way to fix my issue? Perhaps by making it a fully connected model, or anything else?

Weights play nicer if you join them all together then separate after making the weights

So would you say using weights would be helpful in correcting this issue? Do you have any reccomendations?

Well since the characters split into pieces that way, you could always just put each piece to different bones


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Faces, verticies only showing on one area of object

I cannot, for the life of me, seem to find a good answer to any of this.

Looks like a "Solidify" modifier. Apply this modifier and you can access all the faces and vertices.

Is it as simple as just adding one on? I did a solidify modifier already, initial setup

user116231, I thought you did. You'll need to apply the modifier (in the modifier stack) to be able to edit those not-yet-existing vertices/faces.


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Rigging a multi-object person
I'm having an issue I've tried fixing for literal weeks now. I've exhausted all the resources I could, but in short, I created an ultra low poly character that just WON'T rig right. I've attempted doing separate bones, and not using rigify, but ultimately, I imagine this will be a major pain when it comes to trying to do a walk cycle. In the picture, I've circled some areas I'm assuming are an issue, as I'm going with an icosphere for much of the joints (ankle, shoulder, elbow etc).
Am I doing something wrong, for why rigify is ineffective? Is using single bone setups like this feasible for movement and rudimentary animation?

Can you tell what kind of problems are you facing with the rig ?

For sure! This version is the single bone structure, which seems to move ok. But with rigify, everything below the waist doesn't work. Knee sockets are left in place, leg doesn't move with the rigify model etc. It's as if everything from the waist down basically doesnt exist, except for the feet, oddly enough. @Aster17

Hmmm... try not using rigify, it will work

To that point, is doing something like a walk cycle possible? Or using third party items like Mixamo? @aster17

Using rigify will cause problems, especially if you have not cleared the scale. I would say as you have a character with many objects, go with making a rig and assigning each bone to each object. I have some very horrible experiences with rigify and going with bone by bone is much easier. As for if it is possible to do a walk cycle, yes it is highly possible.

Ok that is good to know. I guess my final question is, as far as parenting, and having a multi object character like this, is there a way to have it as a single layer? As it stands, upon selecting an item, say, the torso or arm, it is separate from the character. Is there a way to parent them so that upon clicking on, say, the leg, it selects the whole character? As it stands, it won't upload into mixamo. @aster17

Hmm... that won't work with blender. But, if you select the rig itself in object mode, and if you move the rig, the whole object will move as it is parented. But selecting one bone in pose mode or edit mode won't select the whole object though as it isn't possible in blender.


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Is this possible to avoid ngon in this case?
I have this curved surface:

With subdiv modifier it looks exactly as I want:

So is this the only way to get such a geometry? If I add a connection between vertices, it changes the shape of subdivided mesh.

There is not necessarily anything wrong with having n-gons if it produces a topology you are happy with after subdivision, particularly if the n-gons are coplanar (which they are here). Is there a particular reason you would like to avoid the n-gons in this case? Or are you just asking a question about “good hygiene,” so to speak?

I just watched some Blender course and the guy said that you always have to avoid ngons. Maybe I took it too literally :D

Yes, there are people telling you to avoid ngons. And there are definitely reasons and cases where this is applicable, but it is not necessary (I'd even call it nonsense) to always avoid them. Blender works good with quads, but ngons often work as well. Other programs might prefer triangles. Things like Loop Cuts (Ctrl+R) will neither work with ngons nor triangles. But there are even tutorials on Youtube where people explain when ngons might be even better than trying to make all quads.

Does this answer your question? When should N-Gons be used, and when shouldn't they?


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Shape Keys negative to positive range relation
I would like to get advice from someone who is familiar with the internal mechanism of "Shape Keys(SK)".
SKs can have not only positive but also negative ranges. I would like to understand how exactly these ranges are related ?
When we change geometry in SK value +1, we automatically get geometry changes in SK values -1. Can we make geometry changes so that they do not affect the negative range [-1:0] ?
In other words can we get an SK that will scale the cube up in the range [0:1] and scale the cube sideways rather than down in the range [-1:0].
I saw a similar topic, but it ended up creating two SKs + driver.

Shapekeys are relatively simple.  They are per-vertex vectors that are added to the position of the vertex.  In object space.  So if your vertex is it at object space 0,0,1, and you make a shapekey that moves it to 0,0,2, that shapekey is just the 0,0,1 vector.  Each vertex gets its own vector-- one per vertex per shapekey.
When you assign a value to a shapekey, you are just scaling that vector.  So if you scale by 0.5, that vertex's shapekey vector is scaled to 0,0,0.5; and if you scale by -1.0, that vector is scaled to 0,0,-1.0.  Added to the initial position, we get a final position of 0,0,1.5 or 0,0,0 respectively.
The important thing to understand from this, for purposes of your question, is that shapekeys are completely linear: they cannot be used to represent any deformation that doesn't exist along a straight line.  (So for example, shapekeys are not good for rotational deformations, which follow an arc of a circle.)
So, no, you cannot make a shapekey such that -1 scale deforms it with any different magnitude than 1.0 scale; and no, you cannot make a shapekey such that -1 scale deforms it in a different direction than 1.0 scale.
You can make a shapekey that doesn't deform the geometry at all with an input of -1.0, however, by setting the min range of the shapekey to 0.0.  Then, the input scale is -1.0, clamped by your min settings to 0.0, which is then evaluated by Blender on the mesh as no deformation at all.


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Why does my hair particles look so thick in cycles
I exported a genesis 8 female character as .fbx to blender bald. So I decided to create hair for my character in blender but it's looking very bad in cycles. I'm using blender 2.92. I've tried everything I could but I don't seem to find the solution. Please help guys.

maybe try to add a screenshot, because "very bad" is for me too general word to understand your problem :)

I can't even upload the pictures, it says upload error everytime. I'm new to this site.

You can upload images up to 2 MB in size. Save them in JPEG file format and they are small enough to upload. In contrast, the PNG file format, for example, creates larger files that can be too big to upload.

It's probably the Hair Shape settings that are set too high (default values) and it looks like this:

To better see what's going on, go to Eevee, and set the Hair → Hair Shape Type to Strip. This gives you a better idea in Material Preview/Look Dev mode of how the hair actually looks like when it's rendered in Cycles. The hair particles now will look thick. Don't worry, we will fix it in a moment. Switch back to Cycles.

Let's make the hair thinner:  In the Hair Particles → Hair Shape settings you can adjust the thickness. Go to Hair Shape section, and try these values (for example): Strand Shape: -0.850,  Diameter Root: 0.05 m, Tip: 0.03 m.
These values works best when your model is in real-world size and the scale is applied (Ctrl+A).

This works for me! Thanks! I look for a way to make nice fiber strands for the coconut (the inside core part in brown)


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Adding rigged mesh to other rigged mesh
I have a rigged model of a head that I created in its own Blender file. I have a body that I created in another Blender file separately.
How would I be able to add the head to the body rig so that the head can essentially be a part of the body rig, but contain all of the armature and bones that it had when it was separate? I also want the head the move with the body rig accordingly as you expect a head to do, along with controls for the next which control the rotation and position of the head.

You can join rigs together with cmd+J or windows+J


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Manipulate shader based off moving geometry relative to camera
My intention is to write a shader that will most closely resemble how motion in claymation looks. Specifically, for example, when a character moves their hand, you can see slight abnormalities in the surface texture of the moving part of the mesh, while the rest of the motionless body stays exactly the same.
I have found easy ways to get a nice texture on the mesh and randomize it every frame to give it variation, but I have yet to find a way to discriminate between moving parts of the mesh and static parts.
Furthermore, as I intend to use this to replicate a hand-drawn 2D look rather than a 3D clay look, it would also be ideal for the object's relative position in the camera view to also be taken into account. For instance, a hand-drawn character has to be redrawn entirely if the camera position changes because the perspective changes. Therefore, if the object's position in the camera view changes.
TLDR; is there a way to adjust a random noise factor on a textured object only for faces that move relative to the camera view between frames?
Is there any way to do this, whether that be through the traditional shader editor or scripting?

https://blender.stackexchange.com/questions/49199/water-ripples-waves-on-the-surface-of-an-object/

The easiest thing to do would probably be to use some noise textures to displace the geometry in the geometry node editor

I second what @BrodieLobins said. Except I don't think you'd even need to do this in geometry nodes. I think it would work just by using a displace modifier with a noise texture. When the object data changes, the displacement will update. If it isn't moving, the displacement will remain fixed.

The noise texture certainly adds some variation to the mesh, but what I'm looking for is more of a color-based difference, like in a shader. I think this would be possible by doing some fancy stuff with the normals. Additionally, the noise displacement updates on every face for every frame, which is not what I want. I only want the noise to update for faces that move relative to the camera from frame to frame.

Use something like musgrave or voronoi, that stays constant between faces/frames


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Smooth shade custom normals through geometry nodes
I am trying to follow this tutorial to create a Ghibli-style tree in Blender, but instead of creating the base object using particle systems, I wanted to do it all through geometry nodes instead to allow for a very streamlined method to create and randomize numerous trees in the future.
I have been able to get to the step where he transfers the normals without issue. Then, I attempted to use a geo-nodes based method to transfer the normals from a base object so I didn't have to use modifiers. I have been able to get a pretty nice result:

This method takes the normals from the base mesh (a sphere about the size of the tree) and inserts them into a named attribute blend normals. Then, I can take this attribute vector and use it in the material shader to create the same effect as in the video.

However, the normals appear very blocky and are not smooth. See here:

If there was a way I could achieve the same effect that a "shade smooth" action/node does, then that would be great. However, I see no way to do that since the normals are coming from an attribute and are not affected by object-wide geonodes or modifiers that come after the geonodes. How can I smooth these?
Note: I am using ambient occlusion to get the super black values on the tree shader. I have a hunch this has something to do with the solution. Here are the settings:

There is away to do it in 3.5alpha with the Blur Attribute Node, It blur the normal very well. It may work for you?

Loathe to download an alpha to reproduce, especially when some unmentioned factors (like rendering settings) may interact.  First thing I'd do to troubleshoot is stick a normalize node between your attribute and your Diffuse (not sure if necessary or if Blender does this automatically).  Second thing I'd do is disable AO.  Third thing I'd do is shade smooth in GN.  Remember, you're not really changing the actual normal, which is used implicitly for lots of stuff, like AO, you're just making something that is being treated like the normal by your diffuse (only).


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Everything in pinkish in cycles or "Scene World"

I've been looking back at my blender projects and now all of them are completely pinkish when rendering with cycles (including in the live preview mode)
Also if I'm in LookDev mode and tick "Scene World" under "Shading/Lighting" everything also goes pinkish.
In the World area I am using a HDR file but there doesn't seem to be anything pink there.

The magenta color normally indicates missing textures. Since your whole scene is magenta, it's possibly the HDRi image that is either broken, unreadable due to incompatibility or cannot be found at the given path. Try to reopen the HDRi image, if that doesn't work, try a different HDRi image from hdrihaven.com

Like metaphor_set mentioned the HDRI image couldn't be found at the given path. I had moved the contents of my Downloads folder to another folder because it had been getting too crowded.


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How to UV Map using an Image as the texture source
I am busy with a project and have been struggling for a while with this and was hoping that someone knows the solution to my problem which is with the mapping/ uv mapping.
Attached is 3 images each respectively named Figure A, Figure B and Figure C

The model (which is not mine and is just being used as an example) has been created and is perfectly symmetrical.
Figure A show the left side of the model and Figure B the right side.
My problem has to do with Figure C and its reflection on the right side.
What needs to happen is that the the the texture on Figure C needs to be on the right hand side due to the fact that it is hidden. Is this possible?
Any help with this will be highly appreciated
If you need any clarification please do not hesitate to let me know.
I am anxious to get this project up and running but don’t fully understand UV mapping in blender that well yet.

so you have a a mirrored UV map (like figure A) but need to uv map an image with a projection like figure C?

Some clarification Questions first ;)
"My problem has to do with Figure C and its reflection on the right side." --- Do you want a reflection of the texture or do you want to map the C texture to the Purple Faces?
And what do you mean by "due to the fact that it is hidden"


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Why is my cloth colliding so weirdly?
I am trying to simulate cloth on top of an umbrella, that's blowing in the wind. Right now I'm already struggeling with the cloth clipping through the base of the umbrella.
I tried isolating a single beam of the umbrella's base and have some cloth fall onto that. This only worked rather well, when the beam was parallel to the ground. As soon as i tilted the beam, the simulation got all weird and blocky and started clipping and moving by itself.  Reference GIF here
I'm also attaching the .blend file so you can check out what I'm trying to do. The basic situation is


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Objects not shown in sculpt mode
Blender 2.80
I have a strange effect. In my blend files I have multipe objects. All objects have been sculpted in the past.
Now all are visible as objects, can be selected, textured etc. But in sculpt workspace only one object (the last I worked on) can be shown and changed.
Searching for any reason it became worse. Now the last object is not shown in sculpt mode as well.

Try to push alt+h in Sculpt Mode.

That was one of my first ideas. (sulpt mode, edit mode, edit mode after selecting all) Sad to say it didn't work. The object seems not to be hidden.

please share your file: https://blend-exchange.giantcowfilms.com/

sorry, took me a wile to reduce the size.

You turned on the local view. You can toggle it with the numpad/ key.

That did the trick. Using Blender for 6 month now and haven't  know about this usefull feature.
Again, something learned.
Thank you, I'd vote you up if you put your solution as an answer.

I had the same issue. Above the 3D view port where the layout tabs are (layout shading animation... etc) just delete the sculpt tab where you have the problem and add a new sculpt tab with the + icon. Minor bug hopefully will be fixed


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Even light emmission from area light in Eevee?
So I know that emmissions dont interact with volumetrics (fog in my case) in eevee if you don't bake in the lighting, but the emmission planes are going to be moving. I had the idea to use area lights as a stand in as I can animate them to move with the planes, but I can't seem to find a way to get the light to emmit across the area lights, they're just emmiting from the center like a spot light.
is there any way I can get the light to emmit equally across the surface of the area light? or am I gonna have to just put 700 lights down? I'd render it in cycles, but its a 90 seconds long animation at 60fps, and I don't think my Vega 64 and Ryzen 1600 will finish it before the heat death of the universe.


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Particle Orthographic Clipping Issues
I just got done following a tutorial for creating an asteroid field by setting them to a volumed hair particle system, but I'm having some strange issues with them clipping in orthographic view camera.
First off, in the viewport, the particles appear as they should with the animated moving emitter working fine, but when I enter the camera view there is some weird clipping as the asteroids move (see between frame 287 - 344). I've tried messing with the clip start and end point in the camera settings but I cant seem to get it to work.
Please see the attached file, I've been pulling my hair out over this all morning

Ignore this, I had the camera placed within the asteroid field so objects were passing through the physical camera object. Fixed!


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Modifier "Adjust Edit Cage" - Is there a way to make transformations relative to modifier result instead of the original mesh?
When I select vertices on the resulting edit-cage, the transform tool appears over the original mesh instead of actual vertices I selected on the modifier result. Similarly, if I move the vertices, they move relative to the original mesh.
This makes editing the mesh very tedious without being forced to apply the modifier result first, at which point the changes aren't applied to any mirrored / arrayed portions of the object.
What's the correct approach to this? Is this a feature that exists or will be added at some stage, or am I going about this the wrong way?

I don't think there's any solution available for the moment, it's a thing that should be suggested to the Right Click Select site, for example if you want to edit the mesh of a character that is deformed by an armature, the gizmo won't take the modifier into account, it will be located on the vertex  position before modifier, which is not convenient at all.

Yes, this is quite odd; I expected, and want, that toggle to make it so I can manipulate the modifier result directly (so that it automatically does the corresponding edit on the original vertices). If I understand correctly, the little "enable mesh symmetry in the X/Y/Z axis" toggle buttons that appear in the upper right of the 3d view make it so you can do symmetrical mesh editing with the behavior you want, right? (But sadly those toggles are limited to reflections in the axis directions; i.e. they don't allow arbitrary objects to be used as the mirror, like the Mirror modifier does.)


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Morph curve into line?
I have a Curve object that has a complex shape and is very curved. The vertices are all lined up one after another. Is there a way I can force those vertices into a straight line with an arbitrary distance between them?
Ideally, this could be perhaps saved as a Shape Key or similar so I can animate between the original curve and the straight version. Maybe there's also a way to do this using GeoNodes?

yes shapekeys are a solution, have you tried?

You can create a curve line, move the endpoints to position it (set position node with endpoint selection node plugged into the selection socket), resample it (resample curve) using the same number of points as your other curve, and then all you have to do is transfer the point positions between the two (sample index in vector mode with position plugged into the vector socket) and use the output in a set position node.

Sometimes an one image is more than a thousands words ... :)

@vklidu I think you meant to say: sometimes A picture is worth a thousand words.. But interestingly The phrase has been spoofed by computer scientist John McCarthy, to make the opposite point: "As the Chinese say, 1001 words is worth more than a picture."

@HarryMcKenzie Yes I do :) I don't think it is a place to go deeper here, but I'm definetelly from visual generation :)

Sorry I just couldn't get the result from Hadriscus's answer ... so here is what worked for me. For Blender 3.4+ use Sample Index node (instead of my Transfer Attribute).
To animate transition (morph) change Factor of Mix node (0-1).


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Preparing solid mesh for rig by combining multiple modified meshes
I intend to rig a robot character that has the same form as a human. Right now I have many components of the character as separate meshes (i.e. upper arm, hand, lower leg, etc.), and they all have extensive modifiers to create their final form.
The only way I know how to rig a character is to have all parts of the body be a single mesh. If there is a way to rig all these components together properly while keeping them separate objects, please let me know but I assume there isn't.
Therefore I think the only way to rig this robot would be to join all the meshes together into one. I could apply all the modifiers on each component and then join them to make this happen, but that creates an intense number of faces that I enjoy only having to process during a render right now by disabling modifiers in the viewport. Is there a way to join all these meshes together while somehow keeping the ability to toggle the insane detail in the viewport that would make my computer lag, especially when I need to have multiple of these characters in a scene at once?

You can parent objects to bones. It’s not very efficient, but it does work.

You can also parent multiple objects to the same armature and set the weights of all the vertices in each object to be affected by a single bone.

to bone each object, select the object, shift select the armature, switch to Pose mode, select the bone (it must be blue), then Ctrl P (Parent to) > Bone

The only way I know how to rig a character is to have all parts of the body be a single mesh.

You're in luck! You can parent each object (hand, foot, head etc) individually to the armature. You'll likely want to apply any left-right mirror modifier (a must for weight painting) and move the armature modifier to the top of the modifier stack.


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Make Line Art lines thinner than the minimum
I have a very physically small scene where I am using the Line Art modifier to outline certain objects. I turned the Line Thickness down to 1, but because of the size of the objects 1 is still pretty thick. I can't adjust the size of the scene for a few reasons, so I'm wondering if there is a way to make the Line Art even thinner than the minimum thickness value.
I tried using the Thickness Modifier, but it seems like that also only goes down to this "1" thickness.

How did you do your line art? There are multiple ways to control thickness. You can set it from the render settings, from a gp object, ... Please [edit] your question to add detail. You can also post screenshots and share your file

I have the same problem. Have you solved it?


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Non destructively animate on 2's
Looking for a way to have an armature or any other arbitrary object animate on 2's (only change position/rotation every other frame). I cannot just hold every frame for 2, as I want camera and environment animations to be a regular 24 fps. These objects animating on 2's should be 12 fps.
Using this method it can be done, but this method gets rid of half the animation data and formats it in a way that makes it hard to make tiny adjustments, especially when working with a complex armature, for example.
How can I "convert" a smooth animation to animate on 2's, yet keep all animation data intact so I can switch back to make adjustments if necessary?

I think you can only achieve this with Python scripting. Maybe a Python script could take animation of one object and copy it to another and then use the solution described in the linked question so this would be sort of non-destructive.

This might be of interest. I have no idea what it is or does, but seems related. Might be worth to check it out.


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Export fbx from Maya to blender problem
I have a really big scene in MAYA. It has almost 250 objects, each with a lot of polygons. Some are parented to the other. I want to export them into blender as FBX. So that I get the UVs from maya. Even though I have applied transformations (freeze transformations in maya), when I import the file in blender, many objects do not come in the file. When I open the same in maya, it works perfectly, i get all the objects. I am guessing I ma doing something wrong in blender. if anybody know anything about this, it would be a great help for me

The same fbx is opening perfectly on unreal engine too. Its just causing problem with blender

When importing, there are a bunch of options on the right of the popup windows. Make sure to check all the relevant ones. Also, after importing in blender, go to window / toggle system console and see if any error was printed


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Skip frames in rendering
This might sound weird. I have a scene with alembic files. There are chunks in the timeline which do not need to be rendered. For example in a 200 frames timeline I want to skip say 20-51 and then 110-167. I cannot do this manually as I will be leaving my PC to render overnight and to save the render time I do not want to render the redundant parts. Is there a way to setup the file so that I render the parts I want from the timeline?

This addon called Loom is exactly what you need.
It allows you to specify ranges and specific frames that you want to render or skip. It's even possible to render every nth frame.

The addon allows to render single frames, multiple frame ranges as well as subframes, either directly within Blender's UI (as usual) or in a new terminal instance as background process in case you want to continue working while rendering.

From: How to render specific frames of animation

This will be a better answer if it includes a description of what Loom is and what it does.

Good point. I've added a short description.

@RichSedman Funny that this one-liner, now even has reached the same number of up-votes as the original answer by the author.

FTR: I hadn't seen that other answer before. I've been using the addon for years. Also funny that this answer got more up-votes than my answer here ;)

This is life changing. Thanks for sharing

Sure thing. Please don't forget to mark as solved ;)

One workaround could be to animate the collection/scene visibility so in the frames you don't need the render, you set up everything to be not rendered (you'll get black images).
You'll have a very quick render for empty black frames.
Here's a reference:
https://stackoverflow.com/a/17260936

Thats a very good idea. In case there is no legitimate solution this would be the best work around

You could do it with a few for loops if you're familiar with that as shown here: Python Render Specific Frames


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What is the best way to take animations from Maya to Blender?
In our studio the animations are done in Maya and they are rendered in blender Eevee.  Eevee saves a lot of time in rendering but the time is wasted in setting up the files for render. Right now we convert the files into alembic to take them into blender (Fbx format is not suited for this because somehow the fbx coming from maya does not work properly in blender). but the problem with alembic format is that we have to texture the character every time we take it into blender. Suppose there are 16 files for an episode in maya. So we have to take 16 different alembic files and open them in 16 different blender files and texture the characters 16 different times.
If anyone out there can tell a way to speed up things then that would be really helpful.

Alembic for meshes, FBX for armatures. The only thing you can do is writing scripts to optimize your "pipeline" eg. trying to recreate the shader tree from arnold. However, takes time as well.

So we need a guy who can write scripts for us?

That's the way studios handle such issues for decades... paying a Technical Director to create a so called pipeline.

Related or dupe: https://blender.stackexchange.com/questions/57531/fbx-export-why-there-are-no-materials-or-textures/57541#57541

Does this answer your question? .fbx export why there are no materials or textures?


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Update child coordinates relative to parent
I'm facing an apparently well known issue with Blender that was already described here.
Basically, when I create a new object at world level and then make it the child of another object, its coordinates stay coherent with world and there's no easy way to update them relative to the parent. I need positional data of my objects in relation to how the hierarchy is organized because I have to plot them outside.
A pratical example is when I generate bounding boxes for one or more objects. I used this add-on by sambler to make the BBs, though they get created at world level by default, whereas I'd like to create them as parents of the related items, just one level up, regardless of where they're found in the hierarchy. If I make the BB then manually move it to the desired position in the hierarchy, I come across the "freezed" coordinates issue described above.
Do you have any suggestion? Thank you!

Insert a bounding box as parent.
Does a child object inherit the matrix from the parent?
Can slip in a new parent

Copy the object, clear modifiers, constraints and animation data
Make the copy the parent
Set the copy matrix local to identity, in this case with basis and parent_inverse both identity.  As shown in link above when calculating the world matrix by chaining the matrices up the parents, an identity local matrix does not contribute to the result.
All local transforms that were on input mesh are now transferred to the bbox parent.

Test script, select a mesh object, run script.
import bpy
from mathutils import Matrix, Vector

def bbox2mesh(ob):
    bbox = ob.copy()
    bbox.constraints.clear()
    bbox.modifiers.clear()
    bbox.animation_data_clear()
    faces = ((0, 1, 2, 3),
             (4, 7, 6, 5),
             (0, 4, 5, 1),
             (1, 5, 6, 2),
             (2, 6, 7, 3),
             (4, 0, 3, 7),
            )
    me = bpy.data.meshes.new("BBox")
    me.from_pydata([Vector(b) for b in ob.bound_box], [], faces)
    bbox.display_type = 'WIRE'
    bbox.data = me
    return bbox

context = bpy.context
ob = context.object
coll = context.collection
bbox = bbox2mesh(ob) # make a copy
ob.parent = bbox
ob.matrix_basis = ob.matrix_parent_inverse = Matrix()
coll.objects.link(bbox)
context.view_layer.objects.active = bbox

This seems to work pretty well, though it can only manage single objects. Is there a way to create a single bounding box for multiple entities too (like sambler's does)?
BTW huge thanks for the effort!


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Animated textures on a mesh plane?
I have a flat plane and a series of .png images that I want to have displayed on my plane as an animation.  I don't really know how to achieve this, as I've tried using "Image Sequence" on a Image texture node in the Materials section, which didn't work.  I enabled the AnimAll addon, but I cannot seem to find any tutorials that use the newest version of Blender (I'm using 2.91).
I'm relatively new to Blender, so any help is appreciated!

An image sequence used as texture for the shader should work fine. Please add more detail on what you did.

The images have to be named with the same base name followed by a number.

The simplest way to import them into blender is to use the Import Images as Planes addon.
File > Import > Images as planes.

Select the images you want.
Press N or click on the gear icon on the right of the window to enable the options and select Animate Image Sequences

Or manually add an image sequence node Add > Texture > Image Sequence. Set the number of frames and start frame.
Then just enable Auto Refresh.
To have the images on a loop, use Cyclic


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snow texture isn't realistic as tutorial
i am following a tutorial link below, i follow all the tutorial step and even copy the same nodes but the result is very different as shown on minute 10:19
https://www.youtube.com/watch?v=393zz7KDa_c&t=619s
the tutorial is made in 2021, and now i'm using the new blender 3.00
i tried to upload the blend file but it's still too big even after i compress it

Cycles or Eevee? Could be that? Turn up the roughness on the snow to 1 and change the specular to 0. Add a bit of a noise texture over the top and add a displacement node.

Cycles, i did try switching between cycles and eevee nothing change much. i did try your suggestion of roughness and specular but not much of change as well. in the original node is already included the noise texture and displacement node, as i mention before all the node is even setup by the youtuber and i just copy it.


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Removing unwanted edge
noob here, i'm trying to clean up the surface edge as indicated on red circle, from reference the surface should be smooth and no line, i don't know why it happens.
i also screenshot the vertices (geometry is clean imo) but i guess because some of the area i use knife tool to clean up and the loop cut isn't goes through from top to bottom as shown in the image. any idea how to fix? Btw i have also applied subdev modifier as well. thanks in advance

jINU.jpg

hello please share your file: https://pasteall.org/blend/

@moonboots sorry having an error in pasteall, but heres the file on dropbox https://www.dropbox.com/s/b5ly4mrld549iei/20220622%20Glock.blend?dl=0

You have an inner face, remove it:


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Is blender a software used in metaverse?
I'm a Graphic and UI/UX Designer and I would like to start designing for the Metaverse. I would like to know if Blender is a software used in 3D modeling for Metaverse. If it isn't, could you advise me in which softwares are the most used?

Depends on what you need from it. It's an all-round 3D package capable of modelling, sculpting, animation and rendering. Its applications include motion graphics, CGI, VFX, video games, movies, VR and more. So yes, it will probably find use when the 'metaverse' materialises too, but like Alexandre said, it's all speculation at this point.

it looks like it's the new word for Second Life, no?

@moonboots no.  The 'verse is supposed to be composed of virtual words that are decentralized (in the networking sense) and under control of differing adminstrative agencies.  Of course, that meaning will probably change.

Perhaps, but a lot of money is being spent by large companies, including Apple, Facebook, Google and Samsung to make it happen.  More likely what emerges will be different than what people envision from reading Sci-Fi and so will probably renamed; but the idea of visual navigation in AR/VR isn't going to go away.

@MartyFouts The “corporate dystopia”-type theme seems to be holding up well so far.

@AlexandreMarcati It seems to me that the difference between self-driving cars and what's missing from the net to achieve the 'metaverse' is akin to the difference between brain transplanting and finding the right tweezers to remove a  sliver.  The concepts for the metaverse date back to ARPA experiments in the 1960s. What has been missing, from a technology standpoint, is inexpensive virtual/augmented reality interfaces and sufficient inexpensive network bandwidth.  Both of those are inevitable.

I have never used blender but I know that blender supports import and export of USD(universal scene description) which is a platform for interchange of data between metaworld and 3d applications.

Metaverse is Yet Another Marketing Jargon (YAMJ) that has no agreed meaning; although Wikipedia simplifies the definition to

a network of 3D virtual worlds focused on social connection.

The Metaverse, under that definition, does already exist, and is growing.  Samsung, for example, has a collaboration with Decentralland that has placed 800 or so Samsung virtual stores in the 'verse.
Since one of the aspects of the Metaverse is Augmented Reality (AR) and there are people using Blender to develop AR specifically for the metaverse, then yes, by example, Blender is a tool that is and will be used in the Metaverse.  At least until the marketing people move on to another term to describe the online social experience.
In general, expect that Blender will become increasingly more common in any 3D environment building, whatever it is called.

... Third Life... Fourth Life ... Fifth Life,,,,

Whenever someone mentions the metaverse I think of Geocities and end up giggling.


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Blender 2.93 and 3.0 Sky Texture and Environment Texture
Trying to understand why in 2.93 Sky Texture or Environment Texture does not work at all.
But in 3.0 all is well?

found the issue. Viewport shading turned off

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.


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Collection panel
While working at Blender, I accidentally closed the Collections Panel. Unfortunately, research didn't helped me find a way to return it, I hope you can help me.
How to open Collections panel?

Hard to tell from your question, but what you're calling “the Collections Panel” is probably the Outliner editor area.  Either switch the Editor Type of one of the open areas (upper left corner) to Outliner, or open a new area and switch its Editor Type to Outliner.

This answer is for Blender 3.0 (the current version), and may be different if you're using something else.


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Importing FBX causes all scene animations to become slower
I have a scene with animations, but when I import any fbx it changes something with the animations that makes them play slower; so I cannot import anything unless I want to reanimate the entire scene. The place on the timeline does not change, nor the keyframes, nor playback scale. I've tried restarting Blender, unchecking options at import screen, being in different modes, having different things selected, importing into different collections; I cannot think of what might be causing it.

Figured it out, decided to undo/redo the import and look around to see what changed, and I noticed the sequencer time changing. Took awhile till I looked at the FPS and that is what changed, apparently the FBX's FPS was 24 and my project was 30, so every time I imported it changed the FPS. It never occurred to me that importing an FBX would change the projects FPS, glad I know now. Thanks for the help!

The (Probable) reason this is happening is that the FBX file is just a big file. One way you can tell is by looking at the amount of FPS that is playing. You can see it here:

When the text is red, that means that blender is taking a long time to calculate the animation. The main reason this is happening is that your PC is not very good (Or the FBX animation is just a high quality animation that takes blender a long time to preview). There isn't really a good fix besides upgrading your PC but to make it play faster, you could get a lower quality version of the FBX or try Baking the Animation

Thanks for your response, at first I thought it was the fps, but I did some testing and fps does not drop when in non material mode, but animation does slow down. Doesn't seem to be an fps/pc issue, it seems that importing any fbx slows my animation down on the timeline. There is no numerical change or keyframe position change, so what is causing the slow down I do not know.

Do you think you could share the FBX and .Blend files?

To add to above comment. Use https://pasteall.org/blend/


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Rigging and assigning weights to a round mouth
I'm trying to rig an object (a sink, actually) to make it "speak"; using the overflow of the sink for the mouth :

I managed to rig a round mouth with bendy bones :

But I'm quite new to rigging, and I can't find the correct way to define the influence of the rig on the geometry.
The mouth should be capable of doing some mouth expressions; nothing really too advanced, but I would like to make it smile, whistle and yawn.

A bit like in Alice in Wonderland, but I don't need it to be as good as that.

Almost nothing else than the hole should move, but it would be nice to have a influence around it (eg. if it whistle, the rig would move a bit of the geometry around the "lips" forward.
I did tests with vertex groups, Weight Paint, but it never looks good.
I also had some attempts with booleans (mouth separated from the sink) but it didn't look good.
How would you handle this?
Blend file.

maybe try the Spline IK constraint? 3rd solution I cite here: https://blender.stackexchange.com/questions/116124/how-to-rig-a-cartoon-style-hose-limb-cartoon-arm/116128

Have you tried assigning only the near vertices instead of basically all vertices as you did so far?
Besides, what you should always do is to have a root bone. For all the bones that are not supposed to deform the mesh, disable their Deform option, and then if there is any vertices that you don't want to deform with a bone, you assign them to the root bone. That will avoid issues, especially if you ever export your model. It should look like this https://i.imgur.com/wReCidq.gif

Your mouth needs more geometry to deform around the lips. As already mentioned your control bones have the [X] Deform option enabled. That's causes shading & deformation issues. Here is a quick test with a few support bones around the mouth and moved the bones a bit inside the "face" (Y-axis). These bones have the same purpose as the root bone, basically, they limit the deformation influence. But there are still deformation issues: https://i.sstatic.net/XQcBs.gif

I didn't knew the Deform option, thanks.  I added some geometry.  But how do you assign vertexes ? With automatic weights, then refining it manually ?

If you want to assign the vertices to the root bone as L0Lock did you need to use Weight Paint or select the verts in Edit mode and assign them to the vertex groups.  I've just used Automatic Weights. The support bones did the trick. You can refine it manually. (But I'm bad with manual weight painting and try to avoid it.)


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Armature chain follow a path
I'm trying to create a chainsaw type of animation using bones. I may be approaching this from the wrong direction but I would like to create a chain of bones and have them follow a path.
I used the SplineIK constraint to create the shape but I'm not able to get it to animate correctly on the Bezier circle.
This is about as far as I got, but I can't actually move the bones.

I'm able to get one unparented bone to move around the circle but never a chain of bones.  Any advice would be appreciated! I really hope I can get this to work!
Thanks in advance

Check this http://blender.stackexchange.com/questions/8235/why-is-the-curve-modifier-deforming-strangely

It doesn't look like they are using bones.  I'm trying to create a rig rather than use than apply an array modifier to a mesh.

Constraints

Consider a follow path constraint.  Which can rotate objects along the curve.
The curve hugger bones can have parents but must NOT be connected.  The cutting teeth can be connected to the hugger bones.  I assume the geometric normal bones are cutting teeth.
I do not think Spline Constraint is favorable.
Consider a conform modifier.  No rotation.
If you are really daring you might consider rigid body chain links.  Some people consider these situations unstable.

I just saw this today, great advice.  I ended up doing exactly that last night.  I attached a helper object to a path follow constraint. I then created separate bones for each helper.  This solution is ideal because the bone actually rotates as it spins along the path.   Thanks for the suggestion.

This is what I did.  The oval is a path. I attached each square object as a helper and offset them evenly around the path.  Then I attached a bone to the helper.  It's simple but I did the job.

Exactly what I needed.   Thank you!


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How to get an "extrude" modifier
I'm defining a shape that is a prism, i.e. it can be obtained by extruding a 2D shape along the Z axis.
How can I do this with a modifier, so that I only have to update the top (or bottom) shape, and not select both vertices each time I want to move a pair?
Here's my shape (which already has an array modifier with rotation):

The closest to what I want is the "screw" modifier, with angle 0, but I can't set the number of steps to 1, the minimum seems to be 2. The resulting mesh has an extra extruded step in the middle, as can be seen below, which I'd rather avoid for performance reasons.

Is there any way to have some kind of "extrude modifier"? I tried the "screw modifier", which gives what I want, but with 2 extrude steps instead of one. I tried the "mirror modifier", but the two copies aren't connected (no vertical edges and faces).
Note that I want this to be a modifier, so that I only have one real vertex for each top+bottom pair. Otherwise I can just extrude and move along the Z axis, but then editing further the shape is a pain.

have you used the solidify modifier yet? It will take flat shapes and add extra geometry to give thickness.

@zeffii Thanks a lot, that's exactly what I needed. Don't know why I didn't see it, I thought I tried all of them. I'll accept that as an answer.

+1 for the screw modifier! It helped me extrude a 2D curve.

The closest modifier to what you seek is the Solidify Modifier. One reason it's not called the Extrude Modifier is because it does a lot more than a simple extrude. For instance it can extrude in two directions simultaneously by using the Offset parameter.

The normal direction of the faces determines the direction of the new thickness .

This use of the normal direction explains why a few stray edges (which weren't part of any face) were not spawning a face (like extrude would do). Not a problem in my case, though. Great answer!

I think it's a reasonable question, and it's reasonable to assume something like this would be called an Extrude Modifier. This might help others find the  Solidify Modifier sooner.

good answer, but an extrude modifier would still be nice as it'd allow to work on lower-dimensional geometries. extruding a vertex yields an edge, edge yields a face. Solidify seems to only work reliably on faces.


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Adding materials to more than one object
Is it possible to add a texture or material to more than one object at a time?

Like all objects have the same material? The materials must be apply one time for each mesh. You cannot select multiple objects and apply one material to all of them like expected in other graphic software.

Add a material to one object. Then select all of the object (making sure the one with the material is the "active" object), hit CTRL-L and select "link materials"

@ajwood this could be an answer :-)

similar question

Could you provide some more info about your current setup? E.g. What render engine you are using?

It's possible link the materials on a selection of objects to a single "active" object.

Add an material to an object:

Select all of the objects you want the material on, then select the object from step 1 (it's important that you select that object last; it needs to be the active object). Hit CTRL+L and select Materials

This is an easy way to copy a material to many objects.
First the object with the material should be the active object while all the other objects you want to copy the material to are selected. Then press the "Copy Material to Others" button in the material tab of the property window.

For 2.8+ you can go to the 3D View header menu Object > Make Links > Materials

You can also access it from the material slots dropdown Copy to Selected option

Materials are always copied from the active object to the others selected. Shift clicking on an already selected object makes it the active one.

Also you can select all those objects you want to assign material to and execute the code:
#assuming there's image loaded in Blender and called 'sky_1'. It's the one you'd like to assign
img = bpy.data.images['sky_1.jpg']
imageTexture = bpy.data.textures.new('Image_Texture', type = 'IMAGE')
imageTexture.image = img

#check presence of material with the same name
if bpy.data.materials.get("textureMaterial") is not None:
    materialToApply = bpy.data.materials["textureMaterial"]
else:
  # create material
  materialToApply = bpy.data.materials.new('textureMaterial')
  materialTexture = materialToApply.texture_slots.add()
  materialTexture.texture = imageTexture
  materialTexture.texture_coords = 'UV'
  materialTexture.mapping = 'FLAT'

#loop through selected objects and assign the material
for x in bpy.context.selected_objects:
  me = x.data
  me.materials.append(materialToApply)

The small advantage of this (at least for me, I always check twice which one is active if transfering materials) is that it doesn't really matter the objects' selection order in this case.


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How can I assign an image texture gradient along a circlular ring?
I was recently working on a project of modelling the Solar System. When it was time for Saturn I couldn't assign the rings texture on the model (Circle - rings of Saturn).

I couldn't unwrap the rings correctly. What is the best way for assigning the texture on the circular rings?
Rings texture

Desired ring effect

Assuming all your faces are quads already, first select a ingle face and unwrap it using the Reset option so the UVs become an orthogonal quad.
In Edit Mode select all your faces making sure you specifically click on the one you initially unwrapped, so it remains the active face.
Now unwrap it using the Follow Active Quads option.
In the UV Image Editor turn on the option Constraint to Image Bounds under the UV menu.
Rotate your unwrapped faces 90º if necessary so their orientation follows the ring image as desired.
Move them so they fit to the 0,0 coordinate then using scale resize them so they completely fit within the image boundaries. The Constraint to Image Bounds option should make sure everything snaps into place easily.


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How can I make the effect of moving an object in a very high speed?
I've been planning to make an animation of moving a quad-copter and I was ready to model it and to animate it but I didn't know how do I animate the fans of the quad-copter so that it appears moving in a very high speed as in real life like this Photo :

In this image the fans are out of focus or something like that.
I want this also in my animation So how can I  make it ?

In real life this effect you see on the image is done by the time a camera is opened to receive lights for a very small time (shutter speed). This time cannot be zero so it records a distorted image.
In blender when animating you don't have to do anything. Just tell your renderer to calculate the Motion Blur. For cycles you can find it in the property panel in the render tab.

For blender internal you need to enable the vector pass and use the Vector blur node in the compositor.


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Animating a rolling square wheel effect
I basically want the effect shown in the linked gif, like a cube that roles on the floor and doesn't clip the surface as it moves forward, like a rotating square wheel
I can do the automatic rotation when moving with drivers, but how would I set up the up and down movement as it rotates forward.
https://gyazo.com/8e754d39d4363bd82b1134872f72bbe1

Interesting question. I'm not really much of a math person, not sure I could help much, but you could probably do it with drivers if you could find the right math function. What you need is something close to the middle graph here http://31.media.tumblr.com/1789b63316899d072a23db31f6aec0c4/tumblr_mi301zN7vJ1s5nl47o1_500.gif Source https://www.reddit.com/r/educationalgifs/comments/4pk3nr/unit_circle_square_and_hexagon_graph/

The equation you want for the z position as a function of the x position is z=sqrt(2 - (mod(x, 2) - 1) ^ 2).

Ok a long hard battle with my very limited math knowledge I think I came to an approximate solution.
It is not at all mathematically perfect, meaning the cube will be slightly floating at times, and will appear to slide or drift slightly, but it is as far as I could go.
I would ask anyone with a better math knowledge to improve on this solution.
You will need to set up drivers for it's rotation in such way that say rotation along Y axis will equal pi*locationX

For the tricky part, the Z height will be driver by something like:
0.5+(abs(cos(2*roty-pi/2))*(sqrt((sl**2)+(sl**2))))
Where roty is the rotation along the Y axis and sl will be the length of the side of the cube.
If you want it to react to rotation in two axis jus add the equation above to itself
0.5+(abs(cos(2*roty-pi/2))*(sqrt((sl**2)+(sl**2))))  +  (abs(cos(2*roty-pi/2))*(sqrt((sl**2)+(sl**2))))

For my case with a 1 x 1 unit cube you would get
0.5+(abs(cos(2*roty-pi/2))*(sqrt(.25**2)))+(abs(cos(2*rotx-pi/2))*(sqrt(.25**2)))

Is there a blend file for this?