text:
What is the Reason Cycles Creates Incorrectly Colored/Firefly Artifact Pixels?
When it casts a ray, shouldn't it calculate the color and return that? Why would it create incorrectly colored pixels?

Fireflys aren't incorrectly colored. In theory, you need them for a correct rendering result. They are only a representation of a part of your light that is very difficult to sample for the renderer and therefore magnitudes more noisy than everything else.
The problem with them is that they represent a path that a ray is very improbable to travel on. For example, if you have a reflection or a refraction of a very small but strong light source, the probability that any sample will reflect/refract in a way that will hit this small light source is very small. If it hits it, however, the result shows that this should have a big effect on this part of the surface, so it samples a very bright pixel there.
That would be no problem if, for every pixel, a few samples would eventually follow this path and create a bright pixel there, but due to the small probability, only very few ever follow it and these pixels are then far too bright (because they found the way "too early" and are not yet averaged out by the other future samples that would all not find this way).
On other pixels, no sample will find the way at all (within the numer of samples you set in your render settings) and are therefore too dark (but only very little too dark, because the actual effect of that light on the surface would not be that big).
So if you would render, for example, 10,000 times as long as you do, the fireflies will eventually become more and weaker and, in the long term, become a normal, noise-free part of your light. It's just impossible to sample for that long.

Would it work to scatter the rays at exact set increments to remove random chance from the matter? Or are rays more likely to scatter in a specific direction so this would generate an improper result?

If you take fixed increments, you get weird patterns and edges on diffuse surfaces, that would be like adding several clear (mirror) reflections on top of each other. Even if you add 100 of those, you would still see the lines of what is reflected a bit.
There is also a function of reflection probability over angle, but that could be reproduced through fixed non-even increments I guess.

Yes; also see Moiré patterns.


text:
What does Lightmap Pack's "Pack Quality" option do?
What does the "Pack Quality" option do in the Lightmap Pack settings box? The option's tooltip says Pre Packing before the complex boxpack.

Packing quality controls how efficiently laid out the UV islands are on the texture.
A low pack quality means there is more texture space wasted (but faster unwrap), a higher value means the UV islands are better optimized to use the entire texture, at the expense of unwrapping time.

It seems to be very quick regardless of quality. Why don't they just hardcode it at 48? Is there anything else it affects, such as stretch?

The speed differences will only show up when you are unwrapping models that have a lot more geometry than you see in the example Mike shows.  Basic scenes usually process quickly no matter how slow the algorithm.

source: Stack Exchange

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

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text:
Hide back faces in 3D View?
How do you hide back faces so that you only see faces when its normal is facing the camera? When exporting it for use in a game, the face is rendered in only the direction of its normal, so this would be useful to have something similar.

Blender 2.8+
This depends on your viewport shading mode (Solid, Material Preview, and Rendered) and render engine (Eevee, Workbench, and Cycles).
Solid viewport shading mode:
Regardless of your current choice of render engine, this is easily set in Solid mode. Click the dropdown arrow to open the Viewport Shading panel and tick the Backface Culling checkbox.

Material Preview and Rendered viewport shading modes:
Eevee
Backface culling is enabled on a per-material basis in Eevee. Open the Material tab and, under Options, tick the Backface Culling checkbox.

Workbench
Go to the Render Properties (camera icon) tab and, under Settings, tick the Backface Culling checkbox.

Cycles
There is no checkbox because Cycles lacks backface culling as a specific feature. You will instead need to use a combination of three shader nodes to achieve the same result on a per-material basis. Downstream of any existing nodes (immediately before the Material Output node), insert a Mix Shader node with a Transparent BSDF node connected to the lower Shader input and a Geometry node's Backfacing output connected to the Fac input.

You find the Backface Culling option in the Properties Panel N shading section while in Object Mode.
The effect with a default cube and one partially removed face.

When renderer is set to Game Engine the Backface Culling option is also available in the material's settings.

I have posted an alternate updated answer for Blender 2.8.

Sorry about the downvote, but it made the difference in bumping the up-to-date answer to the top...

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

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Is it possible Animate the Compositor node parameters?
In blender compositor Ineed to animate some Node parametors like Transform, Colore curve, Set alpha values etc.. Is it possible Animate the Compositor node parameters?

Of course. As (almost) everywhere in blender:

Insert a keyframe by placing the cursor over a property and press I
Move to a different frame in the timeline
Set the property to the desired value
Press I again for a second keyframe on this property

Alternatively, you can just right click on (almost) any property and choose Insert Keyframe:

Dopesheet & Graph Editor:

Alt+I removes a single keyframe, Alt+Shift+I removes all keyframes of a property.

Alternatively, you can just right click on (almost) any property and choose Insert Keyframe.

the key you press in 1) , is it an uppercase i, lowercase L or pipe-symbol | ?

@AbdulAlHazred It's lowercase i (insert).


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Is there a way for, Blender animation to flutter via flash flr file format
I am looking for a way to export Blender animation to .flr file format?
flare for flutter: https://www.2dimensions.com/about-flare
They are using the .flr flash file format to export.

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


text:
Blender 2.8 Video editing - annotation
Do you know if you can annotate a video in Blender?
I have tried to d + mouse draw, but I need to control when the grease pen stroke is shown.
I am trying to add circles to a video sequence, to bring attention to an area.
Thanks in advance

You can actually render video with annotations, by clicking: "view" in your viewport for video editing.
And then do render sequence animation.

The annotation tool is an internal tool for the user, it is not for adding visual drawing to the rendered output.
In the VSE, you can add a scene strip, which means you can create a circle using geometry or a grease pencil object in the 3D view and add it to the VSE.
You can also add a single image to the VSE. So you can save a circle as a PNG with a transparent background and add that to the VSE.

can I also directly write on a video in such a way that my drawing/writing is animated as well?

@yogabonito The grease pencil can be animated and rendered, so yes you can add that result over a video, either with the VSE or the compositor. You would add a background image to the 3d view camera to see where you are drawing.

Thank you @sambler :) I have figured out how to do it with the compositor. How would it be possible in the VSE? (I mostly use the VSE anyway and would like to avoid the nodes ;))

(when I go to Add->Scene I only get "No Items available")

@yogabonito from 2.80 the VSE prevents adding the current scene to the VSE (its a dependency thing) So you need two scenes, one with the grease pencil the other can be an empty scene to use in the VSE. Top right next to the render layers to create a new scene.

Thank you so much @sambler! :D


text:
How to handle image creation, search and deletion properly?
Tides are changing and so is the Blender Python API. I would like to know how to properly create, search for and delete an image as my own experiments show confusing results.
At the moment, I have troubles finishing my script for spritesheet generation. It renders animation frames, saves them, loads to actually have access to the pixels, inserts those pixels into a new pool of pixels which will finally be assigned as pixels of the spritesheet. This works fabulously, however, I have problems creating the spritesheet image from scratch while only maintaining one image of that name (older ones might exist from previous script runs for example).
In my version of Blender (2.72) bpy.ops.image.new does not return the image object but a rather useless finilization-message. This means, I have have to grab the image from bpy.data.images by name if I don't want iterate over all of them to check for more matching attributes beside the name. There is the catch: Blender automatically iterated the name of already existing image names and seemingly does this differently from time to time. How am I suposed to know exactly the way, the automatic names are numbered? And even if I know that, why must I iterate over all images with a similar name until I identify the one with the highes number behind it? This seems inpractical.
Ok, what if I check if an image of that name already exists and delete it accordingly? This mus free the desired name, though it bears some risks in complex working environments. I will have to clear its users as well as delete it completely to get it out off the system for good. And this is what I tried to do in my spritesheet generator (code snippet):
if spriteSheetName in bpy.data.images:
    # delete previous spritesheet radically
    spriteSheet = bpy.data.images[spriteSheetName]
    if spriteSheet != None:
        spriteSheet.user_clear()
        bpy.data.images.remove(spriteSheet)
# create new one
bpy.ops.image.new(name = spriteSheetName,
    width = shPxWidth, height = shPxHeight,
    color = [1, 1, 1, 0], alpha = True)
spriteSheet = bpy.data.images[spriteSheetName]
spriteSheet.filepath = imgDirectory + "\\" + spriteSheetName + "." + imgType
spriteSheet.file_format = imgType.upper()

This results in errors taking place in the Blender Python Api itself:
Traceback (most recent call last):
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\startup\bl_ui\space_image.py", line 414, in draw
    MASK_MT_editor_menus.draw_collapsible(context, layout)
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\modules\bpy_types.py", line 770, in draw_collapsible
    cls.draw_menus(layout, context)
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\startup\bl_ui\space_image.py", line 497, in draw_menus
    if ima and ima.is_dirty:
AttributeError: 'ID' object has no attribute 'is_dirty'

location: <unknown location>:-1

Traceback (most recent call last):
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\startup\bl_ui\space_image.py", line 414, in draw
    MASK_MT_editor_menus.draw_collapsible(context, layout)
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\modules\bpy_types.py", line 770, in draw_collapsible
    cls.draw_menus(layout, context)
  File "B:\Programs\Blender Foundation\blender-2.72b-windows64\2.72\scripts\startup\bl_ui\space_image.py", line 497, in draw_menus
    if ima and ima.is_dirty:
AttributeError: 'ID' object has no attribute 'is_dirty'

location: <unknown location>:-1

So, I am asking you if you know proper image handling via the Blender Python API.
Thanks you in advance!

This:     bpy.data.images.new(name, width, height, alpha=False, float_buffer=False, stereo3d=False) returns the image created.
bpy.data.images.remove(image) removes the image.

bpy.data.images.new is what I sought after. It's easy to release the users and remove the image, now. Frankly, some unexpected bugs (?) in my surrounding scripts occured, but - hey - human error knows no limits!
When in comes to naming

Cool, so this can be marked as answered?

Not yet. Maybe someone has more to add. If it's like in stackoverflow, I would have to wait 2 days anyway to give anybody the final answered mark.


text:
is it possible to make an animation / render of just the glossy passes?
My question is about rendering / animations. Is it possible to make an animation of just the glossy passes, say, without the composite view? Sorry if that sounds a bit simplistic, but I am a noob. Thanks

Here how to in Cycles:

First, enable Glossy passes in Render Layers:

Next open node editor in Compositing mode and click Use nodes

Here is the glossy passes, all of them are important.

To make glossy pass you should combine this 3 passes in specific way.
Add 2 Color mix nodes (Shift+A -> Color -> Mix) Change one of them to Add, second to Multiply. Gloss Direct will add to Gloss Indirect, then this sum will multiply by Gloss Color (Connect nodes in this way):

So, in this point you can start to render

It works perfectly, fantastic answer and description thank you.

@JuJu Please do not add a comment on your question or on an answer to say "Thank you". Comments are meant for requesting clarification, leaving constructive criticism, or adding relevant but minor additional information – not for socializing. If you want to say "thank you," vote on or accept that person's answer https://blender.stackexchange.com/help/someone-answers


text:
Modelling a steel structure frame
I am trying to design a steel structure frame, like this:

Obviously, I can model individual beams of different length and arange them, however, it feels like there should be an easier way.
My second attempt was to use a curve and extrude along path (as in Extrude along path), which works well, except that a curve can not have a three-junction, and corners look weird:

Is there some way to get this right? Maybe a special form of the wireframe modifier, which allows me to give a bevel object, just as I do with the curve?

https://blender.stackexchange.com/questions/53475/how-can-i-extrude-curve-shapes-onto-curve-without-tapering/53486 https://blender.stackexchange.com/questions/66733/how-would-i-smooth-a-90-degree-pipe-angle/66735

Hi there, I am involved in addressing this issue in Blender. This is still in development but closing in on a solution and that'd be great if you could provide some feedback here: https://devtalk.blender.org/t/curve-to-mesh-node-even-thickness-feedback-thread/27271  - Thanks in advance!


text:
Smoothing groups, Hard / Soft edges very confusing
Asked this on rightclickselect but they said i should post it here :
Hi,
Its Christmas, so merry Christmas. With it being Christmas it gives me a bit of time to play about in blender which is nice. however i am still very confused by the mark hard soft edge / Auto smoothing in Blender. in Maya its straight forward and clear as day but in blender i find it very confusing since coming from a Max and Maya background. i watched a video where a guy set the auto smoothing to 180 degrees and them marked hard and soft edges which seemed in his video to work. i tried this with strange results. either i'm doing something super wrong or the system is a bit bazaar. then there is shade smooth and shade flat...which is again another method.
so that is 3 methods?
Auto smooth, hard/soft edge and shade smooth/Flat???
is this going to get simplified / improved with 3 methods to do the same thing is seem utterly confusing to have so many methods all of which from what i see don't really play well with each other and from what I've seen there isn't one that overrides the other. the hard and soft edges seem like the logical winner, if you set it manually that is what it should be IMO.
Perhaps someone with more Blender knowledge and experience can enlighten me to where i am going wrong. Ultimately id prefer the Maya hard and soft edge to be the way to be doing this in blender and with the auto smoothing being a default that can be manually overridden.
Thanks P

Those aren't different methods. They are options related to each other and allowing next one from the chain to work. Smooth shading is in the root, the rest of options have no sense without it. Then AutoSmooth which defines general angle and accepts manual defining certain edges (in Blender this is Mark Sharp). It isn't clear what isn't clear for you regarding to video you watched, I think you should edit the question with video link and explain what didn't work for you

Hi Zak, thanks for trying to help. The main problem i have been having is with having a smooth curve top and flat sides. think i have figured it out now thanks to this video https://www.youtube.com/watch?v=HfDBVjLyQtc
but i don't think its fast or a great way of doing it tbh. from this the best way to do it it not use the hard and soft edges at all and go via the smooth shade and smooth flat method. which is old school imho.  anyway i'll battle on with this.

i still don't get it. here is an example .
if i turn auto smooth off. i get a curve tring to smooth itself vertically even though both sides are set to flat shaded and the polys are set to smooth. the half capsule shades fine here ( they are both the same model)

once i set auto smooth on the curve looks as expected. but the half capsule shades wrongly no matter what i set.

pretty lost. not experienced this in any other program. can anyone show me how i solve this or what i am doing wrong


text:
How do you type fractional lengths into blender?
No, not 1/{number}, {number}/{other number}. Every time I try and type a fractional transformation into blender, it forces me to only type 1/{something} when the reality is most people want as much precise control over the numerator too. How can I make blender do what it is supposed to do and just type any fraction?

I can't reproduce this, at first sight... could you just add the details, Blender version, an example of a field that isn't working?

Blender is forgiving enough to allow you to enter minor equations such as "2m + 1/4m" "5/10cm", or most things that are well formatted.  I'm having trouble understanding your issue.

I'm having trouble understand your statement since you have failed to provide proof what you say is true.

I suppose you are talking about the numerical input of Modal Operators, because in ordinary input field you can input a python expression with no problems.
In modal operators it is different. Numerical input works fine, but the divide / and minus - keys function as toggles instead. / toggles between {input} and 1/{input}.
There is however an expression mode you can enter by pressing the = key first (* also works, which is close on numpad). You can now enter any expression, like 3/2 or 3-2 and it works.
I like to do this rather than having to apply the operator in 2 steps: 1st for the numerator and 2nd for the 1/denominator to have a resulting numerator/denominator transformation.
Note: correct order matters. If you press  / first, you enter into 1/{..} mode. Then if you enter expression mode, you cannot go back and get rid of the 1/{..}. You have to cancel the operator.

that's a clever one!

I am not seeing exactly what you are suggesting. You're saying to type an unrecognized symbol in order to cause a glitch that somehow ends up letting you enter 3/2?

@user14554 yes, try it. Type *3/2 and you'll see.


text:
Is there a tool to remesh an object such that it contains a specified number of vertices?
I am currently making a classifier for 3-D objects that uses vertex data as input, and I am using Blender to create a dataset of 3D objects. For the classifier, I need all the objects to have equal amounts of vertices. Hence I want to know if Blender has a tool for remeshing any object such that it has a specific number of vertices?

Soooorrrttt oooff.  It will require some math on your part.  And it only works one direction (down, removing verts).
You can tweak the Decimate modifier to collapse to a ratio of vertices kept.  If you know the number of vertices you want and the number you have is look-up-able, then you can directly calculate the ratio:
for target vertex count $t$, vertex count $v$, and ratio $r$ , it is simply
$t/v=r$ .
Remember, Blender can remove vertexes all day, but it can't add any.


text:
tracking a simple camera movement
I'm new to Blender and am trying to track a very simple camera movement : I'm moving my camera from down to up, along a straight line.
I'm using a DJI Osmo camera, so that I get a stabilized image.
I've been able to do put several tracking markers which seem fine.

I know in a ideal world I should put some specific markers on the road, but as there are always some cars using it, I won't have a chance to do that.
As I said, the camera movement is very simple : from the bottom position, I move to the top position along a straigt vertical line.

When solving, I put 20mm for camera lens (dji osmo specifications) and 6.16mm for sensor width (again, from osmo specs).
According to many tutorials I've seen/read, I check keyframe and select refine focal length, K1, K2.

I thought I had all I need to get a good tracking result, but to my surprise, Blender goes all wrong !
I get a solve error of 3.6 (suprisingly, it seems each time a click on Solve camera motionI get different results). The lens focal is changed to 150.50mm (!?!), K1 to -488 and K2 to 326227 (!!!).
Is there something specific I should do for tracking such camera movement ?
I've been able to track sucessfully much more complex movements, and have no clues why I'm having such a hard time for this one.


text:
Rotate does not update dimensions
I'm new to Blender and I'm following some tutorial and reading the documentation.
Here is described how to rotate or scale an object.
I imported an stl file that is shown rotated of 45 degrees on z-axis.
When I select, its dimensions are:

X 201 m
Y 201 m
Z 15 m

This is because it's rotated of 45° as said (it's a magic wand, like a rod).
So I rotated it by 45° using the transform panel (or R key).
Well, now it's aligned to the Y axis!
But the dimensions are still the same!
I'm expecting something like:

X 15 m
Y 283 m
Z 15 m

I'm in trouble now because I cannot scale it as desired.
Surely I'm missing something obvious... but I cannot find it out from the documentation.

you are confusing the object Local dimensions and its Global dimensions, if you rotate it in Object mode it won't change its Local dimensions, if will if you rotate it in Edit mode or if you apply the scale, meaning its Local axis will aligned with the Global therefore the dimension will be different in XYZ

If you want to check final size after a rotation, you need to apply the rotation: CONTROL+A > APPLY ROTATION
before rotation applied:

after rotation applied:

more info:

Applying transform values essentially resets the values of object’s
  position, rotation, or scale, but does not actually do anything to the
  object. The object origin point is moved to the global origin and the
  transform values are set to zero. In terms of scale, the scale values
  return to 1.
To apply a transform select the Apply sub-menu from the Object menu or
  use the shortcut Ctrl-A and select the appropriate transform to apply.
  The Operator panel lets you choose the combination of transformations
  to apply.


text:
Usage of indoor HDRI for correct dimensions
Right now, I'm using Blender to render objects I drew (even with other softwares) in order to produce images (or videos) that help to understand the real size of the object in a known context. For example, say I have to draw a soap holder, I want to show it inside a bathroom to easily understand its real size.
As far as I understand, to avoid to model and render every single item in a place HDRIs come to help.
I'm aware they are not a "real" 3D model, in fact I followed this tutorial to create the dome (semi-sphere) where my objects can live.
Still I have hard-time to make the scene realistic. The first question is: how much big should be the dome?
Let's try with an example. I have this table that have a diameter of about 650 mm:

(by the way, how to show dimensions for imported objects?)
Now, without the dome, enabling an HDRI leads to the known "floating" issue:

But using the dome, it looks weird enough:

My goal is to add this table, and other objects, inside the room with the proper dimensions so they look realistic.
Can you give me a basic example please? Or a specific tutorial where I can learn this topic by myself?

You don't need a dome, just use a plane with a shadow catcher to make it look like it's on the ground

@Emir that was what I tried do to before discovering the dome method. I was not able to place the plane like it was the floor... The existing objects in HDRI didn't look well.

I think I would only use a dome for natural landscapes or things where you can match the scale of your objects to the background.
You aren't in control of the hdri, so you can't produce a version of it that matches your current needs.  Scaling your own objects could possibly produce some unwanted behavior.  Scaling the hdri generally is not possible - on one axis it is possible but introduces inconsistencies and camera movement becomes nigh impossible.
The hdri may also be too low resolution to be up to your standards when viewed as a background or a floor- even a very high resolution hdri may have visible pixelation since you're only viewing a small portion of it through the camera.
Some depth of field could work to blur slightly blur the parts of the scene you have a problem with, or even let you get away with lower fidelity assets if you decide you need to furnish a room with blender objects.

Bottom line: use HDRI just for distance/surrounding environments, but for real objects use real models.


text:
How to move the original object after using the spin tool
I'm learning how to make polar array in Blender. I saw this video that, among the other methods, explains how to use the spin tool.
A very simple test:

create a base object, say a cylinder
move to the desired offset from the 3D cursor (i.e. X: 30 mm)
in tab mode, use the spin tool to create the polar array

How to change the initial offset?
Let's say I want to change it from X: 30 mm to 40 mm. If I grab the resulting object it moves all the copies. Instead I just want to move the original object, in other words I want to change the radius of the polar array.

If you want to modifier the original object after the spin, you should use either array modifier or a gn modifier instead of the spin tool.

Spin tool only modifies the mesh once without any non-destructive control after the operation(besides regular Adjust Last Operation panel that is lost as soon as another operation is done). If you wish to be able to adjust the result later, you should use Array modifier in object offset mode with a rotated offset object:

Like indicated in the comments, Geometry Nodes can also be used.


text:
Mathematically precise bisect cuts?
https://youtu.be/raWx4MYjq-4
^^^^^^ Example ^^^^^^^
Hi. Is it possible to make precise bisect cuts in Blender? I can only make them manually, by hand, and imprecisely.
For example, like in the video, say I wanted to bisect the object exactly on one of the 3 lines that you see there. I did it by hand in the example.
I know there are numbers in the Bisect window, but I'm not sure how to operate them. There's no "angle" or anything (which would be helpful, because in this case I could set the bisect to 72 degrees for example (but unfortunately it's not angle based)).
Is this possible?

Well, that's not an easy interface to interpret, is it? First, in the top part of the window is "Plane Point" this is a point on the cutting plane. In your case, I think you should set it to the origin (0,0,0). This is also the pivot point for angle adjustments.
The second part of the window is "Plane Normal." For the Y-Z plane, set it to (1,0,0).   For the X-Z plane, set it to (0, 1, 0) and for the X-Y plane, set it to (0,0,1). In the attached screenshot, it is set to (cos(72°), sin(72°), 0) and the poorly drawn white arcs show 72° for the normal referenced from the x-axis and 72° for the cutter plane referenced from the y-axis.
To further expand, lets cut out Suzanne's face at +/1 36°. I put sin(36°) and cos(36°) into a calculator and got 0.588 and 0.809 so lets see how to put those in:

Wonderful answer! I'm sorry if it's a bit self explanatory after your answer... but, I can't seem to bisect it further for a perfect, 72 degree cut again. Could you help me with that too by any chance?

Does this answer your question or are you looking for some angles?

Oh no, I always select all the vertices for the mesh before I bisect. That way the bisect goes through the entire thing. I'm looking for some angles I think; one way I just did it is by rotating the mesh 120 degrees (why 120 degrees? ) and then performing the exact same cut again.
(Edit: 120 * 3 = 360... I get it, but I don't understand how to do this using bisect (without rotating the mesh)

You were asking for 72°, which makes 5 sections. Cosine and sine of 120° is -0.500 and 0.866, swapping them around and changing +/- signs gets you related angles of 30°, 60° and 150°

Very sorry, I've gotten my degrees mixed about. I've been working on this all day.
I want to cut the mesh into 3 sections (360/3 = 120, so 120 degrees) Basically, if you watch the YT video I linked, that is exactly what I want to do, but using math like you did up there.
Plugging in Cos 120 and Sin 120 and then flipping them does not cut the mesh perfectly into 1/3 of the original...
I found an easier way; make a horizontal cut, rotate the mesh 120 degrees and perform the same cut again. I basically want to do this, but without rotating the original mesh: https://youtu.be/XtTn8qIc-d0


text:
How to interpret rotation_difference when objects are rotated?
I'm having trouble interpreting the output of rotation_difference.
It works fine when the objects are not rotated in world space (as in, flat), but as soon as I rotate the two together, you'd think their rotation difference would be the same, yet the values change.
Here it shows the correct value, "Right", when the objects are not rotated in world space:

But when I rotate them together, like this, the output of rotation_difference is different, giving the "error":

In both pictures, A -> B is 90 degrees to the right of the plane (in object space.)
I'm sure there's nothing going wrong, but I would like to know if there's some better way to decode rotation_difference so it works no matter how the two objects are rotated in world space.
In the first picture, rotation_difference outputs:
<Quaternion (w=0.7071, x=0.0000, y=-0.0000, z=0.7071)>

and in the second picture it outputs:
<Quaternion (w=0.7071, x=-0.4867, y=0.4148, z=0.3018)>

It seems there's a way to achieve what I'm trying to do, but it does require that the object has its own local transformations; i.e. this will break if you rotate the object and Ctrl A --> Apply Transforms.
Nonetheless, here is the relevant code I used:
obj = bpy.data.objects['Cube']
cur = bpy.data.objects['Vert']

face = 1
normal_OBJ = obj.data.polygons[face].normal.to_4d()
normal_OBJ.w = 0
nw = (obj.matrix_world @ normal_OBJ).to_3d()

normalCUR = (cur.data.vertices[b].co) - (cur.data.vertices[a].co)
normal_CUR = normal.normalized().to_4d()
normal_CUR.w = 0
nwCur = (mwCur @ normalCur_local).to_3d()

rd = nwCur.rotation_difference(nw)

angle = round(math.degrees(rd.angle), 4)

# This is the important bit:
axis = rd.axis @ mwMol

And print(axis) and print(angle) should now output the same values no matter how the two objects are rotated together.


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Is a there a way to automate this texturing workflow?
I am currently texturing a bunch of assets, and the way I am doing it is painfully slow. Here is my process:
Let's say I have a texture that is 123 px by 123 px.

In my blender world, 1 meter = 1 pixel. Unit Scale (under Units) is set to 0.50.
Now, lets say I have a square that is 246 m by 543 m.

So I go to texture the square by adding an image to the base color, and go to the UV editor and align the vertexes to the UV bounds, it looks like this:

A bit stretched, but that's ok, I say! Now, I have to divide the square's dimensions to the texture. So, 246 / 123 = 2.

Now I do the other side, so 543 / 123, and I get 4.41463414634. So I copy that number, and paste it to the other vertex side.

Ta daa, the square is no longer stretched, and I can move the UV around as I like.
Here's the problem: I'm fine with doing that once, but when I have to do this to 300 different squares with the exact same texture, it becomes painfully slow. Is there any way to have pixels match meters? I've tried texel addons, but they didn't seem to work for some reason/I don't know how to use them. Perhaps the texel addons are the answer, I'm not sure. Any help with this would be appreciated.

It seems this node setup works:

I set it once, then apply the scale to all the objects that use the material. Alternatively, set the bottom option of Vector Transform from Object to World to get a different effect (try rotating the object).


text:
weird behavior of sheepit renderfarm
Recently I notice the weird behavior of sheepit renderfarm client. It appears when the client works within a couple hours.
"Project to check rendering capabilities" For half an hour render time?! I know its sound paranoid but its looks like mining.

This looks like an advertisement rather than a question.

You can review and build the code if you want be sure https://github.com/laurent-clouet/sheepit-client

I'm voting to close this question as off-topic because it is about third party services

That's sounds reasonable, however SheepIt is a free service dediceated only to Blender Cycles. This looks similar to any other questions about specific Blender addons or export to other software to me.

This is perfectly normal. It displays the last rendered frame while rendering another one. You can see the name of the currently rendering project - it is not the test project that is rendering.


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Boolean problem...Help
I want a made circle hole in my mesh and this is happend

try to add some geometry near by.

If you go into edit mode after the boolean operation, you will see that your mesh has bad geometry that needs to be fixed. Your mesh should consist of tris and quads. Instead of boolean operations you want to use proper geometry

As a lazy solution you can try apply Boolean, enter edit mode and create face loop of quads around hole which was cut. That should prevent from too bad shading problems

Possible duplicate of Applied boolean modifier leaving shading artifacts with flat shading


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Mirror shading problem
Why this is happends,i am add a miror modifier and move edges to cliping point.If I click on smooth shader i have a black line on miror line..
Plese help

maybe you have a face inside?

I don't have :(

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

Or some other service, if you prefer. Personally, I avoid that particular site because of its TOS, but of course it's up to you. Or you don't have to provide it anywhere at all; it's just helpful sometimes.


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Can anyone help me to set lights on my scene?
I am done my project with modeling and texturing.In this case this is Marantz Vintage amplifer, but problem is that because I don't have idea how I can set light on scene to look like commercial photo and realistic like one of my first render.

I have a model and black world background,two spot lights and that's it.
Can anyone have idea how I can set lights on that scene.
Here is complete scene file, feel free to give any idea.
https://www.sendspace.com/file/q3vezo

I'd suggest creating a studio like lighting setup, similar to what is used for product photos. For an easier solution you could use a studio HDRI and a backdrop.


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Video Sequencer rendering low quality
I'm having a problem with rendering my animation with video sequencer, my rendered frames are .PNG and high quality, yet when I render them in video sequencer the final result comes with poor quality
Outputs:
Encoding
Container: MPEG-4.
Autosplit Output is checked.
Video Codec: H.264.
Output Quality High Quality
Encoding Speed Realtime
Post Processing both Compositioning and sequencer are checked
Display Device sRGB
View Transform Filmic
Look high contrast
Squencer: sRGB

Can you show us a frame from the rendered .PNG and the same frame after you get it as an .MP4? it's possible your problem is due to the frames being compressed into a new file format and container, your solution might be rendering with a different file format like .AVI

or better: provide your blend file -> did you check output properties - x/y resolution?


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Armature attaching to mesh on contact
Beginner here. I have encountered a weird problem.
Without parenting, as soon as any armature touches a mesh, they somehow connect and move together.
I cant figure out how I caused this and how to turn that off. Can anybody help?

I have a newly added bone, entirely unrelated.
Mesh is in a different spot.

I have only moved the bone towards and into the mesh. This movement is not connected to the mesh, I can move it freely as long as I do not let go while inside a mesh.

However, if I let go of the button and the armature touches the mesh, from this point on, when I move either the mesh or the armature, they move together.
I do not know how to fix this.
As I said, I did not actively parent the armature, their parent tag is empty, neither did I had the mesh selected while adding the new armature, the mesh does not have any modifier except subdivision surface, and it happens with every armature I might add. What am I missing here?

Share your file. https://blend-exchange.com

Simply turn off proportional editing. It's not the armature that is controlling the mesh, but the fact that when you move an object with proportionale editing turned on, every other object nearby will be moved.

Thank you. That fixed it!


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How do I make a collection dissapear and reappear?
In my animation, I want the destructable object to replace the non destructable clone right before the impact frame, but I cant seem to keyframe the renderability of the collection, any way to fix this or to make a collection dissapear and reappear?


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The textures of a model do not bake into a single new UVmap
I imported in Blender a .fbx file from Unity. It's a jungle hexagonal tile made of many meshes that I joined together to form a single object. I've been trying to bake all the textures in one UV map so that, once imported the .obj file, I can get all the textures in Tabletop simulator. Problem is that after baking the new texture image I'm baking onto, the image is still all black, as it was before baking. I don't understand what is going wrong. Here's how I went about it:

create a new UVmap
select it and Smart unwrap the object
pack islands
create a new black image texture (size 2048-2048 - No alpha)
With the old UV map on and the new one selected, I went to the node editor of each original atlas and added a UV map with the new UV map as content, connecting it to a Texture image with the new texture image. I also added a UV map with the old UV map connecting to the main texture image.
with the new image texture node selected in each atlas I baked (diffuse, no direct and indirect) but the new texture is still all black!
Here's a pic of the node editor of one of the many atlas. I think that the problem must be here somewhere.

Unless you are going for lighting effects, don't bake diffuse. Try to use nothing but an emission shader (and your textures) and bake the emission pass.

Thanks, I'll try that.


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Values to straighten wave texture?
I am using the wave texture and am faced with a dilemma: by default, it is rotated in some obscure way. I want the bands of the texture to be aligned with each axis (x, y z) but cannot for the life of me figure out the rotation values required to do so. Any help?

It is probably just easier to recreate it using math nodes rather than trying to align it to axis.
Use a Math Node set to Cosine; as input use your desired texture coordinates like Object or Generated.
Add a Separate XYZ node and use the desired axis as direction, then multiply it by any value to control density of the waves.

You can still run the output through a color ramp node to control progression and color, and covert the whole thing into a node group for simplicity sake, to make it visually cleaner, easier to reuse or port to other files.

Thanks so much. I also did some playing around, and found that adding an "Absolute" function to the end of the equation very closely mimics the wave texture. 10/10 answer though.


text:
Usage of taper object
I'm learning about tapering objects watching tutorials and reading questions.
Still I have some issues understanding how it works.

Please, take a look at the attached blender file.
What I did:

created the "Path" curve
created the "Section" curve
created the "Taper" curve, duplicating the "Path" and moving on the X axis
applied all the transformations
set Section as Geometry > Bevel Object on the Path curve
set Taper as Geometry > Taper Object on the Path curve

Now, if I try to move any handle of the Taper curve on the X axis the extruded profile changes abruptly with no real control (just 1 pixel from shrinked to the original size).
My goal is to make the upper part thinner and the lower part fatter.
Actually, I would like also to change the cross-section along the path: the upper part should be close to the circle, while the bottom part larger on the X axis (like an ellipse). But I think I can easily achieve this second step just scaling the resulting tapered object.

https://blender.stackexchange.com/questions/58564/curve-bevel-function-scale/

@DuarteFarrajotaRamos ... Ha  OK can be closed as dupli ...

Taper
Taper is 2D info ... your egg object takes radius (or size of profile object) from taper's distance on Y axis (X axis represents start/end of your "egg" curve.

Since Taper is controller, scale the "Section" object to 2m (I don't know why ... I would expect 1m like when Geometry > Bevel > Round > Depth), than distance of Taper's control points on Y axis corresponds to radius.
No Taper
BTW for such shape you dont have to use a Taper ... you can just select control point and adjust Radius ...

... and instead of your "Section" you can use already mentioned Geometry > Bevel > Round > Depth
Instead of Subdivision modifier go to Curve Data Properties and increase Resolution Preview.
Oval
To make bottom part oval profiled you can use Lattice modifier or Mesh Deform modifier.

Thanks for the hints! I'm going to study and try the last ones since I don't know them yet

Do you suggest to begin with a torus, then?

No, use your Bezier Circle, and instead your Profile and Taper objects use just parameters (all available) under Curve Data Properties.

The taper object needs to be an open curve and only the distance to the origin on X and Y will be taken into account, not on the Z axis, so you should have a taper object that looks like that (note that for your main object I've changed the first point of the curve with the Bsurfaces addon > N panel > Edit > Bsurfaces > Set First Points):

Thanks, in most tutorials they duplicate the path object - hence my confusion!


text:
Objects and floor being cut off when zoomed in
I've seen tutorials on this site from the old lay out, but even after editing the "Clip Start" setting, when I'm in the 3D Viewport, it still clips.
Can anyone help me find out what I am doing wrong?

To what value have you set your 'clip start' setting?

You are editing your scene camera's clip settings, when you really need to be editing your view's clip settings.
Press N to bring up the side menus, go the the "View" tab, and you should find the relevant options.


text:
How do I disable physics for multiple objects at once?
I'm using multiple rigid body spheres to fill a mesh after I converted them from particles to mesh. Now after a few frames of them jumping around and reaching equilibrium(almost), I want to freeze them relative to the mesh since the mesh will need to move afterwards. I am not able to use the "copy from active" when the active object doesn't have any physics enabled. I can only copy physics of an object and paste it to the one without any physics but not the other way around. Is there any way I can do this?

Just found out the (obvious)solution. Select all the objects with physics - go to object[top left]> Rigid body> Remove.

In addition to OP's answer, you can also click Apply Transformation before removing the Rigid Body to freeze any Rigid Body Sim you want in place.
For example I used it to stick a stack of children's clocks in place.


text:
In a fluid simulation, how can I make an "inflow" fluid type pour into a "fluid" fluid type in one simulation?
For example, how could I have a water pump pour water (inflow) into an existing pool of water (fluid)?

I know that this video:
https://www.youtube.com/watch?v=qaaMaWazr1E
does not show exactly what you seek, but his method is amazing, and I think it could be adapted to what you are trying for a very realistic result.
His "pool" is a plane on which he uses Dynamic Paint and the Wave system in the modifiers tab to "paint" the splash of his particles on that plane.
If you try to follow along with his video, I suggest you watch it, first, then follow along in Blender, because he shows several things that don't work, in order to explain why, and then show the correct way.
However, even with that, he makes a mistake that totally messes up the final results, by deleting his first dynamic plane. When I recreated this, I, instead, used a second, and left the original for later use. You'll see.
However, there is another way, that might better suit your purposes.
Within your fluid domain, where you want your pool, make an object that fits the size of your pool, and, while assigning the fluid parameters, set that object in the Physics tab with a "Volume Initialization" of "Volume". Assign the same material as you would your "Fluid Domain" material, so they don't contrast. (Or, better yet, at first, make them different, so you can see the effect, then make them the same for your final renders.)
Here is a sample initial setup:

... and here is how the existing pool is assigned in the physics tab:

That frame is the very first frame in my example where the new fluid hits the existing pool, so you can see that there is an immediate interaction.
Um, I'm still new at this, so I wasn't sure how to upload my .Blend file for you to examine. I hope the images help you see that it does work.

Just make a longer animation, where you pour some water until your pool has enough inside, then stop the inflow with a keyframe and start it some time later. Then, only use the needed timeframe.

To add to Grimm's answer make sure to change time to reflect it. As in time start and rime end.


text:
Can CGI elements emit light when in real video?
Blender super noob here.
Is it feasible to have, lets say, a neon sign made in Blender, emit light onto its surroundings when placed in a real life video?

this is feasible, but it requires manual laber. (I'm not very good at vfx, I'm just saying that it can be done.)

You would camera project parts of your video to objects within the Blender scene and those objects catch the surrounding light. Than you would comp it over your footage.
here is a small YT Video that shows the process with an Image but you can also use Video or Image Frames - but be aware that you have a good tracking or you will get sliding effects
https://www.youtube.com/watch?v=p9IfDeNU8K0
ohhh and for sure
BlenderGuru's Camera Mapping tutorial
https://www.youtube.com/watch?v=B9r9tKX5olY
if you set up your scene like this, you can have your NeonSign lighten Up the surrounding Areas.

Thank you so much! I will check out your recommendations!

@TylerKeene if you you find that answer helpful, please vote it p and tagg it as helpful so that other user with the same problem can find it easier and know that it can be a help.

@TylerKeene does it help you ?


text:
Number of markers in VSE?
I'm wondering if there's a way to show the number of markers you have in a sequence in the blender VSE? Thanks

Run this code in the Text Editor:
import bpy

scene = bpy.context.scene
print("Number of markers: "+str(len(scene.timeline_markers)))

And in Menu > Window > Toggle System Console see the result.


text:
Texture Paint suddenly changes color
I was painting a figure. I hit 'S' to get the color picker to save the colors I was using for clothes, then I saved the color I used for skin. I painted some of the clothing, then went back to the skin. Suddenly the brush is using a different color. I pick the skin color again, and it goes back to the other color (yellow in the screenshot color).
I removed the earlier color and picked it again. It made no difference. I got rid of it and color picked from a different part of the figure. No difference.

What version of Blender are you using for this? Do you mean that you press S to sample and then save as a swatch there? Do you then press S on top of the swatch, or are you just pressing the swatch to switch to it?

I'm using version 2.8. I press S to sample and save it as a swatch. Then I click on it later after I've saved it.


text:
Painted Texture does not appear when rendered
I painted this Amazon figure after creating an image called 'metallic'. I painted this material and the figure looks the way I want. However, none of this paint shows up when I render it. I realize there's another image called _17054_Amazon which didn't get painted.

I'm new to Blender and I'm this is a noob mistake. I'm confused there are two images, but one figure. Can I replace image _17054_Amazon with the iamge 'metallic'?

how does your Shader Editor look like? You need to plug an Image Texture node (with the image loaded) into a Diffuse

are the materials set correctly?
did you save the image? last version that I used only renders the saved file.

I agree with this troubleshoot. Save the file, then go back into the shader editor and ensure the correct image file is plugged into the shader. If that doesn’t work, send us a picture of what it looks like rendered.


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Animation Nodes Error When Checking off Add-on
I have installed Animation Nodes from animation_nodes_v2_1_windows_py37.zip in Blender 2.80. Installation seemed fine. When I check off 'Node: Animaton Nodes' in the list off Add-ons, I get an error message

I saw on the Animation Node Github page the answer is to download VC_redist.x64.exe from Microsoft. Sorry, I should have read that before posting - hopefully this will help other people searching for the same issue.


text:
Can't rotate and scale anything
After I animate one UV texture on plane with AnimAll add-on, I can't scale and rotate any object,in object mode.Only can scale and rotate if I select all in edit mod.
Please help

Maybe deactivate the Manipulate Center Points option?

Thanks this is solve my problem...


text:
How do i go from my object displaying mesh to smooth
I was wondering why my object displays vertices lines and the other doesnt im not sure how that happened.

You can change how you want to display your geometry per object here:


text:
photo realistic sss skin shader... i need a great node setup
So i was looking for a great node setup, heres my results so far and my node setup. I was wondering what i was doing wrong because it doesn't look good, also i know light setup is important but for right now i want to focus on the nodes than play around with different lighting angles.

Scrapbook for skin. Collections of nodes for realistic skin with pores. You might find something after page 7 or 8. https://docs.google.com/presentation/d/13-D6Y6u8yJ4mbcBAp6-lmsaie3s9psxlexm2yBkqLEQ/mobilepresent?slide=id.g14f82c173dcbf2d2_0

you should begin by increasing the Roughness value, the material is too glossy, it looks like oil


text:
How can i delete a uv map in the img editor
so i have a model with couple different uv islands and i was wondering is there a way to unwrap the model and delete a uv island in the img editor?
I unwrapped the whole model and am trying to delete a uv island..

Hello :). I'm afraid you cannot really delete a part of a UV map. The whole object is either unwrapped, or not unwrapped. What are you trying to achieve? Maybe there's a better way.


text:
weight paint is deforming my mesh?
so im trying to build a face rig and using only the bottom lip bones i assign weight paint and im wondering why its deforming the mesh like that and what a possible solution would be thanks

Is the rig in rest pose (same as in edit mode)? Did you Apply (Ctrl A) rot and scale to both mesh and rig?

yes but that only reset my pose i think it has to do with weight paint...


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Why is the mirror making secondary lines?

Why is the mirror modifier making secondary lines and how can i make this not happen its on origin to geometry bounds center the lines are only there when i have the mirror modifier on with x axis location of x is set to zero and i have no shape keys

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

Use punctuation please. This "one-sentence" is quite hard to understand given that image doesn't explain well the original state of mesh and what modifier actually adds to it


text:
Using dynamic topology makes weird artifacts
When sculpting with dynamic topology, there's this weird sort of artifacting issue that occurs when using the subtract option with the crease brush, where it doesn't make a crease in the way I expect it to, but instead sort of flattens out the area, while only slightly creating the the crease I want (I usually use crease, but it seems like any subtraction version of a brush causes weird artifacting).

This sort of thing doesn't seem to happen if I only subdivide it and sculpt without dynamic topology on. It may also be notable that the same thing happens in Blender 2.8, for what it's worth.

what Detail Size rate have you chosen?

Current it's at the default 12.00.

Perhaps decrease the size, perhaps it's in Collapse Edges mode instead of Subdivide Edges? Hard to tell, could you please share your file?

Lowering the detail size does seem to have help (and in 2.8 too), thank you! Though here's the original file if you think it may still be good to take a look at it. https://app.box.com/s/aedg5kram9hzgox0j8xxljts4kswbhf9

Yes your Detail Size must have been too high, and as your Refine Method was either Collapse Edges or Subdivide Collapse it has created large triangles

In your Properties panel > Tool > Dyntopo, Your Detail Size is too high, and as your Refine Method was either on Collapse Edges or on Subdivide Collapse it was creating large triangles and bad artifacts. So, decrease the Detail Size from 12 to 2 for example.


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Why am I getting weird Normal colors when baking in Substance Painter?
I am trying to bake a simple shape but I am facing issues when the bake is done. The normal colors look very distorted and I feel that if i use it in any game engine, it'll be a mess. Are these distortions fine or is there any issue i can fix?

The baked model looks fine.
Smoothed low poly to minimize seams after the bake

Shouldn't Flat faces have a constant color?

Hello ! Which seams do you want to minimize exactly with smoothing your mesh ?

@Gorgious Hi! The seams that pop up here: https://imgur.com/Y59xghN
This is baked on a flat shaded low poly.

If you shade smooth the low-poly before baking it will distort the normal map

@moonboots In that case, what do I do to minimize the seams and also get good normals?

I'm not sure what you mean by minimizing the seams, do you want to have rounder edges? In that case you need to create a bevel on the low-poly, you can't create the illusion of a bevel with a normal map if this is what you were trying

Got it! I'll just bevel all low poly objects then. Thanks!

If you shade smooth the low-poly before baking it will distort the normal map. If your goal is to create rounder edges on your low-poly you need to bevel them, you can't create the illusion of bevelled edges if they are sharp.


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Whenever I use the particle system to emit from volume, it just ends up emitting from the faces. Is this a bug?
I've just started using Blender particle system and rigid body stuff. I've tried to emit particles from the volume of the mesh but they just sit on the surface of the mesh no matter what I try to do.
I want all the particles to be inside the mesh from the beginning and not on the surface. Is this possible?
I was following this tutorial - https://www.youtube.com/watch?v=1gM8yEMFMjg

The particle system with random distribution

Here is the system with jittered distribution
Emit from Verts and faces yield similar results with some particles escaping the mesh in the first frame itself.
Here is the blend file if I wasn't able to explain it properly: https://drive.google.com/file/d/1eRWzE-IprJ0dP3l_zxkEso5sTgC0Vbq7/view?usp=sharing
Any help would be appreciated!

You probably need to flip the normals to get the volume filled with particles.

You just have to invert your normals.

Problem: I'm not sure
Could be solidify modifier

Fix to make it emit particles from the volume.
Press ctrl + c on the object
Open another window (don't close)
remove everything
Press ctrl + v in another file
Remove all modifiers and particle system
Remake particle system
Copy iy back in the other file.

I've tried what you suggested but it still behaves the same way. However, I did get around the problem by using another object to emit the particles inside the first mesh.

@Praneeth Try taking off the solidify modifier.

The end frame for your simulation is the same as your start frame. That means that your particle simulation will run for one frame (in which it will emit the particles), and then stop playing.
Simply change it from 1 to the desired number of frames you want your simulation to run for (if you don't know what this is, then just set this to the number of total frames your project is set to render, which I can see is 250).

Simply put, set the Frame End to 250 in the Particle System Properties tab.

The particle setting that i put was so that all the particles are emitted in the first frame and the lifetime is for 50 frames(after which they will disappear). I want my scene to have the mesh full of the spheres from the beginning, hence the frame end is at 1.
The problem I'm facing is to place all the particles inside the mesh and not on the surface or outside. Hope I clarified myself!


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Is there an easy/right way to join these vertices?

I'm making a hexagon-type shape here by first outlining the edges and then proceeding to the centre as mentioned in some tutorial I followed. Is there an efficient/right way to go about this without making a mess of the topology? Links to any relevant tutorials are appreciated too!

if it doesn't create any artifact you don't need to join the vertices, you can keep a ngon, if that's the question

@moonboots It didn't create any artifacts yet. I've heard ngons are to be avoided at any cost so I wanted to join the vertices up. Thanks for correcting me!
But what about some models that shouldn't have any ngons? How should I approach fixing the topology there?

what do you mean by fixing the topology? Again, if you're talking about the fact that you have a ngon, you don't have to care as long as it doesn't creata any artifact

Hello :). If you don't want the n-gon there, remove it, and use the Grid Fill function. It will create quad grid to fill the hole.

@moonboots By that, I meant if an object has an ngon and it does create artifacts, what would be the steps required to {connect the vertices to create quads/fix the topology} which would in-turn fix the artifact? I am referring to the practice which is shown here in a tutorial. [https://www.youtube.com/watch?v=SvJkGEn4UpQ&t=1741s]

@jachymMichal Hi! Unfortunately, grid fill didn't work in that example above since it dint have the edge loops.

you have a lot of ways to reduce the amount of vertices, take a look at this site: https://topologyguides.com/ for example the part called Optimal Edge Loop Reduction Flows

Thank you! This helps a ton!

The Grid Fill's error message is a bit unclear. You can use Grid Fill on one loop, but it needs even vert count. So most of the cases it helps if you subdivide one of the edges or dissolve a loop.


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How do I get the armature/bones to fall with gravity?
I cant get the mesh to not wig out after it falls.
I'm guessing I need the bones to fall with the mesh so the mesh deforms relative to the bones. I can't figure out how to do this and nothing I've googled has helped.
Any help would be greatly appreciated!

You can't. Armature are not supported in context with the rigid body sytem.
The behaviour occurs, since the Armature is evaluated after the rigid body simulation. You can't change the order of evaluation (as in Maya e.g.).
Shapekey however, get evaluated before rigid bodies.
Use this hacky script to transfer your animation into shapekeys. (Refine it first, then use it!)
To make this script work, the active object:

has to be selected
has to have an Armature modifier name "Armature"
has to have no Armature modifier name "Armature.001"
has to have a "Basis" Shapekey

import bpy

scn = bpy.context.scene

frame_range = [1, 200]
for i in range(frame_range[0], frame_range[1] + 1):
    scn.frame_set(i)
    bpy.ops.object.modifier_copy(modifier="Armature")
    bpy.ops.object.modifier_apply(apply_as='SHAPE', modifier='Armature.001')
    bpy.data.shape_keys["Key"].key_blocks["Armature.001"].name = str(i).zfill(3)

key = bpy.context.selected_objects[0].data.shape_keys.key_blocks

for i in range(frame_range[0], frame_range[1] + 1):
    key[str(i).zfill(3)].value = 0
    key[str(i).zfill(3)].keyframe_insert(data_path="value", frame=(i+1))
    key[str(i).zfill(3)].keyframe_insert(data_path="value", frame=(i-1))
    key[str(i).zfill(3)].value = 1
    key[str(i).zfill(3)].keyframe_insert(data_path="value", frame=i)

Disable the rigid body, by checking its animated property.
Create the Basis Shapekey.
Execute the script.
Hide the Armature modifier.

The animation is now transfered to shapekeys.
Disable the animated property again to simulate.

If you wish to change the animation, delete all shapekeys and enable the armature modifier again.

looks like I'm getting a syntax error after running your script. Any thoughts? screenshot

@DavidSkillin The code had some incorrect linebreak due to a markdown error. It now has correct line breaks and indentation.

You wrote Animation modifier.  Did you intend to write Armature modifier?

@atomic Most definitely, thank you for notifiying me.


text:
Problem with curve / spline modeling, scale factor
I'm trying to taper a tube-like (beveled curve) object using another curve. Should be simple ...
But im always getting a strange 'scale factor' and I dont understand where it comes from.
The 'Curve' should be tapered exactly like the 'Taper' (top view). No 'scaling' in x- or y- direction. I watched many tutorials but they dont really help.
https://mega.nz/#!viwAyRCI!dNA4-x5LDpn3DYTxzF6Tf8_sg7DwlMmmQOUsIfaKfuI

Are you trying to make this type of shape result http://pasteall.org/pic/show.php?id=70a324ee5edee6b0ba2f409bebeb717e if yes then i will proceed with the answer

Not really, i'm just trying to control the radius of the curve using the 'taper' curve. But its not following correctly. The bulges are not located at the right position (x position). It seems that the bulges come to early for some weird reason.

The scale seems to be based on the number of vertices (of each curve) not directly on the X position. Try to add a vertex somewhere in your beveled curve.

That sucks ... somehow whenever I try to use these curve features (bevel and taper) in blender, it doesnt behave properly and I end up finding another way ... If its based on the number of vertices its not usable. I will just use the screw modifier on the taper :) ... blender sucks in many aspects


text:
How do I get the screw modifier to go around the Y axis for a 2d Trace
I want to recreate a chess piece (Bishop) by wrapping a side trace around the y axis. However, when I use the screw modifier, it decides the y axis isn't good enough and does this to me.

This isn't just an issue with my complicated line either, it seems that all bezier curves have this problem: here's a example of the what I'm talking about.

This shape, rather than pivoting along the y axis, pivots along a slightly tilted axis of its own. How do I fix this? Changing the center of origin doesn't help.
TL;DR
Is there any simple way to tell blender to screw a trace around an axis ignoring an object's origin?
Thanks!

Looks like you rotated the object used by Screw modifier in Object mode, so apply its rotation with Ctrl+A.

The screw modifier by default uses the Z axis, you can change this in the modifier options.
If the revolution axis doesn't correspond to the world Y axis its because your object is rotated in Object Mode.
Check your objects rotation in the 3D View > Properties Shelf > Rotation (N Key)


text:
Is there a node like MixShader but for the displacement slot?
So I want to apply two different materials and their displacements to an object but I was only able to keyframe the shaders using the mixshader node. Is there a similar node which can be used to keyframe two displacements? Any help would be appreciated!

You can use the factor of a Color > MixRGB to switch from an image to another, and plug the MixRGB into the Displacement node.

Thank you! Worked like a charm!
I was trying a million other ways to solve this but wasn't successful.


text:
I used bezier curves and circles to make a shape, how do i transform it in to an editable object?

I used a bezier curve and a circle to make a claw shaped thingy around the bezier curve, I want to be able to edit the geometry of this shape, but don't know how to transform it in to an object.

menu bar > Object > Convert To > Mesh From Curve.

thanks man, was really struggling.

@moonboots I was just wondering, and feel free to tell me to mind my own business, why you don't seem to up-vote questions you answer?

sorry I don't understand what you mean, am I supposed to upvote them? sometimes I do when it's a non too common one but maybe I don't do what I'm supposed to


text:
GPU not rendering in Cycles
I can't get my GPU to work on any scene.
I have enabled both my CPU and GPU for Cycles rendering. But during render CPU usage gets to 100% and GPU does not go up (below 5%).
Here are my settings:

I tried unchecking the CPU in preferences, and in that case 10% of my CPU is working on the rendering.
The scene I am working on is not the problem because, I tried other scene, like the BMW benchmark for GPU. And still the GPU is not working.
I have all Nvidia drivers up to date (Game ready and Studio).
I tried Blender 2.82a, and 2.83 no difference
I am looking for a solution, thank you for reading this.

How Big is your rendering tile size? It most likely you just set a tile size too big and there isn't much more tiles for 2070s to rendering thing (Since 3500 use 12 tiles).

And I don't recommend you to render on both CPU and GPU since your CPU is not that good compare to 2070s, the improvement should be little and the rendering setting will be hard to control since they need different parameter to work best. (I recently use a 3900x with 1070ti, guess what, 1070ti is still way faster than 3900x)

Thanks for your advice, I will use only the GPU. I tried different tile sizes but apprently my GPU was working correctly, it just that the task manager didn't show it clearly.

Same here.
Just a quick note: Windows Task Manager doesn't show CUDA utilization by default (which is what Cycles uses). To have that show up, click on the "3D" above the graph and choose "Cuda" or "Compute_0" in the drop down that pops up. It will then show correct utilization.

Thanks, I didn't know that. I checked and I'm at 100% cuda utilization, which means its working correctly I guess. My GPU was working fine I just thought it would appear in the overall GPU usage but apparently not.


text:
Why is everything pink?
I downloaded my old Blender project from Google Drive which I made in Blender 2.81. Even though I put all procedural textures, everything is pink. The textures are somehow missing. This is how it looks.

Maybe you also missing hdri? It could cast pink lights. Check world nodes

You also have to change the path to the textures. Else the computer don't know where to find them.

I only used procedural textures. Like vorinoi and musgrave and wave.


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Can't "curve bevel" imported SVG
I'm trying to Object Data Properties > Geometry > Bevel some SVG imported curves, but it doesn't work as expected.
It looks the bevel (either by parameters or Object) are projected in 2 dimensions instead of following the curve as it does with native Bezier or Path curves.
I tryed some solutions like:

Converting SVG to Mesh then back to Curve, but it creates too many points and I lose the actual curve.
Setting different types of curve: Poly | Bezier |  Nurbs
Recalcultating Normals

It may be a noob question but I can only find posts about the another problem with SVG and the another Bevel function (round/ chanfer edges).

Thanks

https://blender.stackexchange.com/questions/91782 https://blender.stackexchange.com/questions/86873 https://blender.stackexchange.com/questions/56344

@DuarteFarrajotaRamos Thanks! Your answer solved my problem. Since the SVG was being imported very small, I was scaling it like 100x in XY but keeping it 1x in Z axys. Scaling it equally in XYZ solved the issue. I really appreciate your help. I was a whole week trying to figure this out. Feel free to post it as an answer, although you already are high scored! Thank you, again!

Hello and welcome. You can instead upvote the answer that helped you.


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How do you convert Weight paint to new mesh layer in blender?
I used weight painting tool to select specific area of an dental model object and I want to convert that selection to new separate mesh layer, is there any way to do so in blender 2.8?
Please advise.

as Trey Harper says, there's a simpler way to separate or duplicate a part of your mesh, but if you really want to use the Weight Paint zone, you need to know that you've painted it has automatically created a vertex group in the Properties panel > Object Data > Vertex Groups, so you just need to go in Edit mode, select this group, press the Select button under the vertex groups list, it will select your group, then shift D to duplicate and P to separate.

I'm not exactly sure what you are after, but if you want to get a new, separate mesh of the teeth weight painted red, there's a simple way to do it.
In edit mode, you could Circle select (press C, mouse wheel changes brush size) and then "paint" the faces you want to select.
Then Shift-D to duplicate the selection.  Then, P will Separate the selection into a new object.
Hope that helps.


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Blender 2.8 API seems to have issues with UV layers
I have had a working exporter for a custom format that worked fine on 2.79, when i moved to 2.8 everything works besides one issue that i cannot seem to understand. Could you please help me out?
The issue is when i write more then 1 UV layer, the second layer is always bugged.
 uv_0 = mesh.uv_layers[0].data
    if len(mesh.uv_layers) > 1:
        uv_1 = mesh.uv_layers[1].data

I get the UV data in this way. Then i loop though the faces.
    for Face in mesh.polygons :
    for loop_idx in Face.loop_indices:

        vtx_2tc.TC0 = V2D(uv_0[loop_idx].uv.x, 1.0 - uv_0[loop_idx].uv.y)
        vtx_2tc.TC1 = V2D(uv_1[loop_idx].uv.x, 1.0 - uv_1[loop_idx].uv.y)

Which worked perfectly fine in 2.79 and lower, the second UV was correct. However in 2.8 the second UV layer doesn't write properly. Half the mesh's second UV is working, half isn't. And i'm not sure where the issue is.


text:
TOPBAR_HT_upper_bar.append add menus in two places?
I try to add custom menus to the menus at the top bar in 2.80. The old INFO_HT_HEADER.append() doesn't work any more. I found TOPBAR_HT_upper_bar.append() to kind of do the trick but I get two menus, one after the workspace tabs (would preferably have it before but I guess that is a feature request separate from this) and one after the view layer menu. Am I using the wrong thing or is this a bug? Here's a super simple menu from an example which gives me the problem.
import bpy

class customMenu(bpy.types.Menu):
    bl_label = "Custom Menu"
    bl_idname = "view3D.custom_menu"

def draw(self, context):
    layout = self.layout
    layout.operator("mesh.primitive_cube_add")

def draw_item(self, context):
    layout = self.layout
    layout.menu(customMenu.bl_idname)

bpy.utils.register_class(customMenu)
bpy.types.TOPBAR_HT_upper_bar.append(draw_item)

If you want additional menus in the top bar you can add them to TOPBAR_MT_editor_menus. The following code adds a menu called Custom Menu with a sub menu that contains an operator. The draw() function of TOPBAR_MT_custom_menu is for drawing the sub menu, while menu_draw() is appended to the TOPBAR_MT_editor_menus in order to draw the menu itself.

import bpy

class TOPBAR_MT_custom_sub_menu(bpy.types.Menu):
    bl_label = "Sub Menu"

    def draw(self, context):
        layout = self.layout
        layout.operator("mesh.primitive_cube_add")

class TOPBAR_MT_custom_menu(bpy.types.Menu):
    bl_label = "Custom Menu"

    def draw(self, context):
        layout = self.layout
        layout.menu("TOPBAR_MT_custom_sub_menu")

    def menu_draw(self, context):
        self.layout.menu("TOPBAR_MT_custom_menu")

classes = (TOPBAR_MT_custom_sub_menu, TOPBAR_MT_custom_menu)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)
    bpy.types.TOPBAR_MT_editor_menus.append(TOPBAR_MT_custom_menu.menu_draw)

def unregister():
    bpy.types.TOPBAR_MT_editor_menus.remove(TOPBAR_MT_custom_menu.menu_draw)
    for cls in classes:
        bpy.utils.unregister_class(cls)

if __name__ == "__main__":
    register()

Switching TOPBAR_HT_upper_bar to TOPBAR_MT_editor_menus solven my problem, thanks.


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Can't find my bones in vertex groups?
I'm trying to weight paint my armiture to my mesh. I put the armiture in pose mode, select the mesh, go to weight paint, but when there I am unable to select a bone. It allows me to paint the mesh, but doesn't weight it to any bones. There are no bones appearing in my vertex groups until I begin to paint, which suddenly produces an item called "Group". I don't know what I'm missing. The tutorials make it seem so simple.

Hello. First, you have to parent the mesh to the armature.

Select the mesh, shift select the armature and press Ctrl P, then choose "with empty groups" option if you want to hand paint them, or "automatic weight" if you want to have a base starting point.

Thanks so much you guys. That was exactly the problem. Doh.


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Boolean creates open mesh / hollow
I have been trying to modify a STL file from thingiverse to hold a boat I modeled up. However, when I use the boolean difference operator it creates a hole in the mesh rather than forming around the subtracted object! AHHHH so frustrating. Does anyone know what's going on?

Make sure both Meshes are Manifold. In Edit mode use the Selection menu to find non-Manifold faces/edges and fix them.

Is the imported stl model watertight?

@rob I couldn't find any non-manifold faces or edges...

@rjg i believe the model is watertight. It appears to be fully enclosed

do you know how I can share so you would be able to see?

You can upload your project here (https://blend-exchange.giantcowfilms.com/) and add the generated link to your question.

@rjg just uploaded the file called "untitled"! let me know what you think. Any help is very much appreciated!!!


text:
Blender, changing Pose of character changes already made animations
I have a cow model that, in its Rest Position, is standing up normally on its 4 legs. Then, i also have the cow in Pose Position, in which the cow is siting. My current 4 animations of this cow are with the Cow sitting, shes either waving or looking around etc. Now i wanted to make other types of animations such as running, but the problem starts when i reset the pose with ALT-G and ALT-R, it resets the cow to its rest position as it should (standing up on its 4 legs), but now all my animations have changed aswell. It seems that the animations are referencing the cow in its Pose Position. How can i simply change the cow's position to whatever i desire without breaking all my animations so i can make other types of animations?

Did you miss keyframing some bones? Might help to add  images or blend file.

ah that might be the problem, for example when i create one animation, my first keyframe i add all channels (all bones), but for the next keyframes, i only add the rotation and location of one particular bone (the head for example, to simply rotate the head left and right, since i'm not gonna need all bones for this) and then the final keyframe has all channels again. Should I add all channels for every keyframe? isn't that a bit "overhead" or computacional expensive once it goes to the game engine?

Actually let me update on that, what i think i should do is the following:
1st keyframe: commit All bones with all channels;;
2nd keyframe: commit All bones, but only necessary channels (if i only rotate the head, then commit all bones with Rotation only) ;;
3rd, 4th, 5th..etc keyframes: do the same as the 2nd keyframe ;;
last keyframe: commit All bones and all channels.

Final update haha: actually i didnt have to do any of what i said previously, basically what i did was all channels all bones in First and Last keyframe, and then the middle keyframes just use the necessary bones. This is what i tought i had in the first place but apparently i didnt. so it's fixed :)

Glad you got it sorted. Consider looking into the auto-key feature (looks like a record button in the Timeline window). It sets keyframes automatically.


text:
Rotate Entire Scene of Objects at Once
Is there a way to temporarily override axis and orientation locks and things to select everything in a scene to rotate it 180° at once? I have a scene with 1,500 objects and many are hidden and others have locks on certain rotation axis and drivers. To have to unhide and unlock and remember how to put everything back would be a nightmare. This needs to be merged with another larger scene with a different orientation
I wish there was a way to put everything in a collection and effect the collection as a whole.

Would a collection instance work?

I've been barking up that tree trying to see if it will work. It works in a test scene I made but it crashes when I use all the actual parts in my scene. May try to make a couple smaller collections and try.

You might be able to write a Python script that rotates everything without the use of collection instances, but the drivers could cause problems if they are orientation-dependent.

I've been looking into how to do that as well... Trying to find how to do a simple python load blender scene and make it Y- forward I think is what I need. Then I can just resave the scene and load as normal. Or if there is something that is a better approach for the entire scene I'm not sure and still haven't solved it. :-(
Any drivers that break I can just fix.

You can actually create an empty, parent all objects inside your scene into  that object whilst keeping transforms (Drag + ⇧ Shift + Alt).
Then you are able to rotate the empty how you want it, and after that unparent the children of the empty. This is like rotating the axes themselves.


text:
Blender show me a blank window in the render window?
I would like to render my model as image, but when I click on render image, blender only shows me a blank window, I just tested Eevee and Cycles, but there is unfortunately no difference. When I click now on render, Blender gives me only black images.
Would be awesome, if someone could help me!

Which version you are using?

I think you don't have a camera in your scene!

https://blender.stackexchange.com/questions/67490/why-does-my-object-not-show-up


text:
how to bevel this?

I extruded this curve out of an svg and converted it to a mesh.
I cant find a way to bevel the marked edge. Both the bevel modifier and the "normal" Bevel tool dont show any affect. why? How can I bevel this body?
(the bevel option in the curves section overlaps in the corners)
I also would have planned to use some kind of variable radius blend if this is possible.

https://blender.stackexchange.com/questions/82188/fill-along-the-front-of-a-path-of-an-svg/82200#82200

You are having problems because the geometry is a mess. You don't want any of those elongated triangles.
I would try it like this:

DELETE all top faces.
See which of the vertical edges can be dissolved without losing detail. - Goal is to have relatively even spacing.
Select the outer edge (green/sharp in your picture) and inset it far enough to have room for the desired bevel. Be careful not to overlap any geometry. In that case you'll need to cleanup manually after insetting.
Alternatively to insetting you could also extrude the edge by scaling inwards and possibly smooth out the resulting edge to avoid overlaps.
Try Grid Fill or manually fill in the rest of the top faces.

After step 3 you could already try to bevel it and see if it gives you a better result.
I hope this helps a bit.

thank you very much! worked out pretty good. But I am still missing something like a varible Radius bevel for the neck joint (the rectangular part where the guitar neck would go). Id like to have just a very small radius there.

It's probably best to manually select the edges and use Ctrl + B in Edit Mode to bevel the edges individually. Where the different bevels meet, you might need to see how it behaves and possibly do some cleanup. But this can be tricky. Another option is to change strategy and basically make two shapes out of the guitar. (Neck joint + corpus) And use a Boolean Modifier set to "Union" to join the two back again. Boolean

@dodododo using bevel modifier you can able to use edges bevel weigth, select only edges that you want to bevel and (in the N panel->item)set the Main Bevel Weigth to a specific value (e.g. 0.5 tells to modifier to apply 50% of bevel in the edge) and in the bevel modifier set the Limit Method to Weigth


text:
box selection went wrong

and I dont know how to get back. Actually I intended to cut the sphere into half by box selecting one half. Accidentely I pressed CMD B instead of just B. Redo not possible, the rest of the model is not visible anymore.

Hello :). Cmd + B sets render region. Use Cmd + Alt + B to clear it.

doesnt work, the box selection appears but nothing changes

Hey :). If the linked answer doesn't help, you'll need to provide more details.


text:
Include images added to 3d model when exporting to glTF, OBJ, or DAE
I have imported a 3D model into Blender, and then used Add Images to place a number of png files inside the model. When I export to glTF, I am not able to view the images within the model.

The glTF Blender addon supports meshes with textures, but I'm not sure about standalone image imports... You'll probably need to create planes and add your images to them. For best results, see the guidelines in https://docs.blender.org/manual/en/2.80/addons/io_scene_gltf2.html.


text:
Paint? Extrude?
I'm relatively new to blender and though i find a lot of it quite intuitive, there is much i have to learn. My project is the Musical Box from Camberwick Green (many under 40 and not raised in UK will not remember this BBC childrens programme), it is a hexagonal box with small skirts extruding from the top and bottom, an isolated image of one skirt below.
what i want to do is decorate the outward facing faces with a kind of gold fluting...? A rough example of which is in the second pic.
Is there a way i can do this by drawing it on the main face and extruding it, so that it has a little thickness and looks like it has been pasted on like a piece of card? or is there some other way? Also how could i duplicate so that it matches up evenly on all outer faces? Sorry if I'm in the wrong place to ask this, but maybe somebody could even point me in the direction of a tutorial which covers this kind of thing? Not had any luck searching, but maybe im wording the search wrong. Many thanks in advance.

First thought is to UV unwrap the Faces the gold will be on and ensure they all over lap(so they will get the same result). Then use Texture paint mode to create the result. Use the resulting image as both the Diffuse Colour and as Bump map. You could also create a Curve and design the Gold as a separate entity with its own material and then Join or parent it to the hexa-ring.

Thank you Rob, Not being one to sit back and wait, i went ahead and did the latter, made a separate entity, i haven't parented it to the hex as yet but i think it looks good so far. Can't figure out how to post the image of progress here though.

You should edit your original question and use the standard image process.


text:
How do I change the MTL File to an actual image?
When exporting my Model and importing it into another engine, It require an Image file as the texture instead of a MTL file, so I was just wondering how I would accomplish changing the mtl to and image file

Investigate Baking with Blender. Baking records all the textures(plus lighting etc) as single result as if it had been rendered from multiple angles.What engine are you importing into?

Just wanted to ask the same :-)

A MTL file is just a material definition. It doesn't contain image data. See here for further (all) details about the MTL file format: http://paulbourke.net/dataformats/mtl/
If you're using OBJ files, you need three things:

the model data as OBJ, contains vertices, faces, smoothing groups and texture coordinates, etc.
the texture(s) (any image format, e.g. PNG)
the material library file (which is referenced in your OBJ file)

See also:

the blender manual about the OBJ file format
this question for OBJ exporting options in Blender


text:
Problem with changing the current area type
Hey when executing this code it works perfectly the first part of it
import bpy;
oldScene = bpy.context.area.type;
print(oldScene);
bpy.context.area.type = 'OUTLINER';
bpy.ops.outliner.orphans_purge();
#it works fine till this end
bpy.context.area.type = 'TEXT_EDITOR';

After that, calling the current area.type will always return an error! Like pointing to a deleted instance or something. I don't understand so far the problem.

If you actually want to change the area, store the area in your variable and change its type.
import bpy

old_area = bpy.context.area
old_type = old_area.type
area_types = [  # available types differ based on blender version check API docs
    'VIEW_3D',
    'TIMELINE',
    'GRAPH_EDITOR',
    'DOPESHEET_EDITOR',
    'NLA_EDITOR',
    'IMAGE_EDITOR',
    'SEQUENCE_EDITOR',
    'CLIP_EDITOR',
    'TEXT_EDITOR',
    'NODE_EDITOR',
    'LOGIC_EDITOR',
    'PROPERTIES',
    'OUTLINER',
    'USER_PREFERENCES',
    'INFO',
    'FILE_BROWSER',
    'CONSOLE',
    ]

for a in area_types:  # cycle through possible area types
    old_area.type = a  # change area to new type
    print(old_area.type)

old_area.type = old_type  # return to original type

Alternatively setup a context override like answer here

Dear Ratt, thanks. The code works well but the thing is like this: I am working on a  python script that executes directly and I want to do purging for all the accumulated data every while without interrupting the code. I want to open the "OUTLINER" from the "TEXT_EDITOR" side and execute "purge" and then reopen "TEXT_EDITOR" again as if nothing happened. I don't know if this can happen but seems so far like a bug or the "context" loses the pointer of the panel or points to another place after changing the screen. I tried to assign this by pointer of location but It didn't work. Thanks.

or actually we can just point to the outliner and excecute the codes there without changuing the current screen.


text:
Update screen using python scripts
I'm working on a new iterative algorithm for generating geometries. I'm trying to update the screen for each iteration on the screen to monitor the results (real-time); blender doesn't respond during the calculations.
Note: I tried this command but didn't work:
bpy.ops.wm.redraw_timer(type='DRAW', iterations=1,time_limit=0)

Suggest also looking  at using a modal (see modal timer op template) and running each iteration in modal Not sure re the wm.redraw_timer op in particular,  running a lot of operators can slow down blender over time. https://blender.stackexchange.com/questions/7358/python-performance-with-blender-operators  btw select code and hit ctrl-K or hit {} code button for code markdown.

This is the right command (Problem Solved):
bpy.ops.wm.redraw_timer(type='DRAW_WIN_SWAP', iterations=1)


text:
Importing meshes from other *.Blend files
I have found lots of solutions for importing meshes from other files in Blender. I have used this method from the official documentation:
https://docs.blender.org/api/blender_python_api_current/bpy.types.BlendDataLibraries.html?highlight=blenddatalibraries
The problem in this is when you import a mesh from a file it will create a new scene automatically. I want to add all the meshes and objects in one object and change their names as soon as it is imported. Are there any methods that could merge scenes together from Python?
Best,
Mahmoud


text:
Colors contour from Python
I have several hundreds of objects in a scene. I want to distinguish between them using colors contour. The color is interpolated according to the size of the object. Is there any possible way to make this happen from Python?

Yes, depending on how exactly you define size

I'll use basically the volume the Bounding Box of the object. If you can help me in this I would be grateful; I have no prior knowledge in rendering in the normal environment (UI) rather than using it in Python.

Can you post (edit into question)  the code you have so far eg calculating volume from bbox.

@batFINGER sorry I did not get your question, but for volumes, it's easy to get the size of the bounding box using the following command: 'bpy.data.objects["Name"].dimensions' and this will give u a vector of (x,y,z) dimensions of the BB of any object. If you want to calculate the volumes of complex bodies you can go to the 3D printing addon.


text:
Cursor location accessing methods
Can you provide me with different methods, or at least one, for accessing the vector of cursor location?
I need anything but the one described in this line of code:
bpy.context.scene.cursor_location

I do not want to access any method in my code using "context"! My code reloads the modules recursively and Blender for no reason I know always loses context when I do so. By the way, lots of people are complaining about losing context in scripts and add-ons after reloading Blender (not in a direct way). If you have any suggestions I would be more than glad.

Suggest if you don't know something ask a question. If it involves code, show code. Try and avoid "hearsay" in questions.

A .blend file can contain many scenes. Each scene has a .cursor_location attribute:
>>> {scene.name:scene.cursor_location for scene in bpy.data.scenes}
{'Scene': Vector((0.9819498062133789, -5.541140079498291, -6.299274444580078))}

If you know the name of the scene, (e.g. 'Scene'), you could use
bpy.data.scenes['Scene'].cursor_location

Thx that worked just fine.


text:
Remesh a selected surface
Is there any modifier that allows me to remesh let's say a one selected surface (triangulation)? I'm working on complex boolean objects. The problem when I apply boolean operations the mesh gets nasty at some point and I need to remesh only parts of the resulted boolean. Later, I will use this mesh as an input to another software so I need a clean stl mesh that works for Finite Element. It could help if someone tells me a trick even around it. I would really appreciate your help.

Triangulation helps a bit with boolean operation (that's what people say). Probably attach a simplified blend or screen with issue. Probably it can be solved in a different way.

Yes, you can!
with
Boundary Aligned Remesh

Go into Edit Mode
Select the messy part of the mesh or just one face
Press P to separate  the selection
Switch to Object Mode and select the separated mesh
Use boundary aligned remesh to recalculate a new triangle mesh (boundary verts will be saved to get a good welding with the source mesh)
In Object Mode CtrlJ join both meshes together again  into one layer.
Go into Edit Mode again and weld them with Merge by Distance.

Voila, you should have a  pretty good result now.  Optionally smooth it a little bit with "relax" using Relax.

Wow this tool is so fricking amazing, it fixes so many problems of mine. Finally brings blender remesher much closer to that of zbrush

Sadly though this isn't capable of merging meshes :( , would be great if you could add that

@Sidney, that's not really possible with this plugin. It operates over the entire mesh it's given, so it has no knowledge of any other meshes to merge with. You will have to do the final step that Oliver mentioned, that of doing a Merge by Distance to connect the vertices back up again.

Hello, I tried the plugin but it does not seem to install on 4.2, anyway you could make a port ? Or convert it to an Addon ?  Thanks.

Remesh modifier does not have a function affecting only a specific group of vertices.
A: I don't think it is possible to Remesh only specific object faces.
Quite hard imagine how this "remeshed" part of model (vertex group) would be merged with original. I think it would result with much more artefact on surface - since it will mix two different topologies.


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Can I get rotation and location value of newly created cube by geometry node?
I use this simple geometry node setup

It just keep generating cubes when I move curve point like this.
newly created cube is rotated on z axis.

and I need to know rotation value and location value of newly created cube by geometry node. I need to use those values to move and rotate the red big cube, which I can't control via geometry node because I need to move it by armature bones, so  I would like to use rotation and location values of new cube as driver values for bones.
Is it possible to get rotation value and location value of newly created cube by this geometry node setup?

May I recommend to read this post: How to expose geometry nodes result as driver inputs ?

I checked it but I need rotation value too.


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is there any better way to keep UV mirrored when I do symmetrical modeling using mirror modifier?
I have one polygon mesh which I always do something to like modeling, UV  mapping, texturing, weight painting, rigging at the same time. I ignore typical workflow when I mess with this mesh. I know I shouldn't touch UV map after finishing texturing, I shouldn't touch bone weight after animation but this base mesh needs something like it.
So I would like to optimize UV mapping workflow, so I made my base mesh completely symmetrical using mirror modifier. it's nice because this modifier lets me have not only symmetrical mesh structure and vertex group but symmetrical UV map too. So I don't need to think about UV mapping again and again when I do something in edit mode. I know if I edit mesh, UV will be broken too but I can edit mesh with texture, which is nice because I use texture as reference. To make it better I will make my texture structure symmetrical. Mirror modifier has an option "Mirror U" so if texture is drawn based on this option mesh with mirror modifier can have asymmetrical texture, but texture needs optimizing too because if I use "Mirror U", typical square ratio texture has lots of dead space in its width area so I will make 2k 2048x2048 texture into width 1024 height 4096 texture. file size is same but it's more efficient because its width area is smaller but height area has more space. I know UV map will be a problem when it's displayed on non-square texture, it will be distorted too but I just need to scale them. Not so hard to maintain.
What do you think? Is there any better way to deal with UV mapping when I do symmetrical modeling? Give me your thought please.