text:
Suspended particles inside a material (procedural)
Inspired by reading this very intense thread about procedural materials, I decided to try and build upon saunam's material of "suspended particles in a recipient" to create a material for a watermelon ice pop such as this (the red, top bit):

The idea is to create a translucent material inside of which are present black seeds. I have created a mesh for the seed with a shiny black material, but also tried creating the seeds procedurally.
However, my node-wrangling mastery fails to achieve what I have set myself to do. When I tweak the node setup from saunam, for example to replace the emission node by a translucent node, or the volume scatter node by a glass node, everything breaks. I'm not sure I understand how the node setup works.
I don't even know if this is possible, but I would really like to procedurally scatter the shape inside the material.
I have tried with a Particle Setting, but it just doesn't stay inside the mesh and the particles aren't dispersed evenly. Since I will be making the object move, I'd prefer to use a material than a Particle System.
Current blend:

I would advise to having the seeds physical made out of mesh, not complicating the material. You can convert particle system to mesh. That way those seeds can also have it's own glossiness, like real seeds have. You have better control over the seeds if they are mesh and better control over material, because it is simpler.

For your purposes, a particle system based setup will work best as any material will cause the grains inside to appear very flat.
Starting with your blend file, on the object Cylinder.001, under Particles > Emission, I set these values:
End: 1
Emit From: Volume
Distribution: Grid
Distribution Resolution: 5
Distribution Random: 1

Now we have an object filled by volume with the grain object. Don't worry that some of the grains are outside the object, we will fix that.
Under Particles > Rotation, I ticked the Rotation checkbox and set the Velocity/Hair Random to 1. This will make the grains appear to have frozen in random floating orientations.
Next, we're gonna need some room to work with our particles. So, with your object selected, press M and click the next open layer to move your object there. Then press 2 on your keyboard to go to that layer.
With the object still selected, go to the Modifiers tab and under the particle system modifier, click Convert.
Now all your seeds are individual objects. In solid 3D view mode (Z), check the outside of your object and just manually delete any remaining grains that accidentally protruded the mesh.
Next, select your cylinder and hide it with H. Using B, select all your grains and press Ctrl + J to merge them into one object.
This will make them much easier to manage. Unhide your cylinder (Alt + H), and with both the cylinder and grains selected, press M and select the original layer to move them back. If you are planning on making your objects move, you can parent the grains to the cylinder with Ctrl + P.
You will discover on your first layer that Blender also expanded your original grain object with the particles. You can either choose to move this object to another layer, or hide it with H.
Here is the result:

Not bad, with the existing node setup. Please note that I disabled depth of field for this render. For a clearer icepop, you can fiddle with the balance between the translucent material and the glass material. I might also experiment with mixing in some subtle volume density or subsurface scattering for a more photorealistic render, but I do not have the time to test right now. Maybe someone else can comment on better ice-pop materials?

Thank you for the thorough answer! I am trying your solution. Clicking "Convert" in the particle system of the cylinder doesn't seem to work (the modifier doesn't go away after I click "convert", therefore I can click it several times and nothing seems to change). When I moved them both to Layer 1, a gazillion new seeds showed up everywhere :(

@MicroMachine Yes, every time you click "Convert", it generates a new set of mesh seeds. After clicking "Convert" the first time, just delete the modifier manually and you should be good to go! :)

Thank you for your answer, I gave it the bounty. I made a variation on it as my answer below, after learning so much from all the answers, I hope it's ok :)

@MicroMachine Your result below looks great! I forgot to mention tweaking the Size and Random Size though; that will definetly make the result even better.

Final:

Overview:
I've simplified node that you've mentioned in question and I've added surface material (really simple, you can use whatever you want instead).
You can control black bits size, distortion, amount and color.

Blend file:

While it is more difficult to control the shape with this method, the "pure" procedural results are quite nice and I will certainly be playing around with the volumetrics myself in the future. Thanks for sharing!

Definitely the second best answer, I would have split the bounty if I could have! Tweaking it was hard but I like the results I got with it. Also, animating it makes the particles stay in position in a weird kind of way and move around... Maybe can be fixed with a different coordinate node? This one is a hard one!

Another particle approach.

Particles setting

Watermelon's seed objects (particle objects) are emitted from volume with inside normal to keep most of them inside the volume.
You can use the seed value (on top of the image above) to try and choose the distribution which fits the best.
Material: watermelon part

A mix between a translucent and a glass shader. Eventually you can mix again with a glossy shader (not used here).
Material: pistachio part

A mix between a velvet shader and a glossy shader. The velvet can add a little softness to the surface.
Material: ice limit

The limit is given tuning the Z generated value with a color ramp.
Material: ice contact

A mix with the Z limit as above and pointiness which provides some kind of randomness around the limit.
Material: mixing them all

Inputs: (1): watermelon / (2): pistachio / (3): ice limit / (4): ice contact
Note: the rendering uses filmic color management with low contrast. If you don't use it the colors will be different (and you may change the color inputs and tune the mix shaders).

Thank you! Good one. I really enjoy your gradient between the yummy mint part and the watermelon one.

(1) What exactly is the "ice contact" supposed to do? It adds a white gradient line over the green/red one when I try. (2) The grains seem to be only rotated 90° from one another (vertical or horizontal), I think it's more realistic to randomize rotation in "Rotation" (3) How do you keep the grains inside the mesh? Same technique as CGEffex?

@MicroMachine, 1/ Ice contact is to separate the 2 parts of the ice it's using the Z value (from 0 to 1 due to the generated input) and is driving the separation line. 2/ OK.3/ PS settings, volume + inside normals + choosing the good seed (underlined in the first image)

I did everything like you did, but the "ice separation" ends up looking like a white line/gradient, and there ends up being seeds inside the green part or through the mesh. But your first image is really good!

@MicroMachine, this is effectively more or less a small gradient due to the color ramp. I modulate it a bit with pointiness (which needs some inner geometry to work), but I think it could be modulated a bit more with a noise for instance.

Ok. I personally discarded the ice separation material, since it made little to no visual difference with or without it, since there is already a nice gradient between the green and red part (good job thinking about this! Gradients can be tricky).

Here's another answer I came up with, a variation on the accepted answer.
Create a Particle System on the popsicle object, and under Particles > Emission, set these values:
Number: 38
End: 1
Emit From: Volume
Distribution: Grid
Distribution Resolution: 3 or 4
Distribution Random: 1
Under Render, click Object, select the "grain" object previously made.
Under Physics, tweak Size and Random Size to make it realistic, add more realism by ticking "Rotation" and turning Random to 1.
When satisfied, go to the Modifier tab and click Convert once, then click on this button:
￼
and delete the Particle System with the "-" sign.
Remove the ones that are sticking out of the Ice Pop mesh, then join all the grains (CTRL + J).
Create a translucent material for the cube, that takes into account the thickness of the material in order to disperse the elements present inside it, such as this one (borrowed from here):

Render with a Clamp Indirect value of 3.

To move around the whole thing easily, select everything (for example in Wireframe Mode, with the C cursor selection), then press CTRL+G, a green outline will appear around the elements. Then select a member of the group and then press SHIFT+G and select Group and it will select every other object in that group which you can now drag around, scale etc. Source


text:
I cannot create an array on a text object, only along Y
I have created a text object, and would like to make an array of it along the Y axis.
Arrays on X and Z work fine, but I cannot seem to make an array on Y.

I can't understand why this wouldn't work? I've tried to change some of the settings in Array, but no success...

I guess along Y works... but your object is flat, so 'relative offset' will create duplicates at the same place. To do that, use 'constant offset' instead. Note that your object is rotated, so along Y (global) is Z (local) for the object.

Oh yes! That fixed it. Thanks! For some reason I thought the value "1" implied some distance (like creating an array along the Z moves it up a certain distance), or that the planes were never "0" depth. Thank you! Solved it.

Relative offset is relative to the object's size. 0.9 = 90% of the size, 1 = the size, 2 = 2x the size

An object which has no thickness can be duplicated by an array modifier using relative offset but the duplicated objects are at the same place as the original, as relative offset's values are relative to the object's dimensions.
It appears as if nothing was happening.
If you want to see these duplicates in this case, use 'constant offset' instead:

source: Stack Exchange

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

sort: votes


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"Record" doesn't create keyframes
I'm just a beginner with animations in Blender, but how my teacher showed me is that you can click on the "Record" button, place your object, turn "record" off, move the object, hit record again to create keyframes, turn off Record", etc.
I've done it a few times successfully, but the new animation I'm working on doesn't create keyframes:
Object in position 1

I turn "Record" on and move the object:

But no keyframes were created!

you are in edit mode, that recorder works in object mode, since keyframes era created for objects. if you need to change the "shape" ogf the object, you need to learn to use shapekeys (and you can animate them too)

The record button is a toggle for automatic keyframe insertion, it is not meant to be clicked on/off to insert keyframes. To insert keyframe in object-mode use the I hotkey.

the record button may work also in that way, but just does not work in the edit mode...

@m.ardito you gave a good answer, make it so that I can accept it! Also, thanks :)

The Record Button keyframes automatically every change in the Viewport.
But that recorder works only in object mode, so not in Edit Mode, since keyframes are created for objects. Also it works for all properties in Blender wich already have one keyframe inserted. If you change them then they are automatically keyfamed too. If you need to change the "shape" of the object, you need to learn to use shapekeys (and you can animate them too).
However, you can also keyframe and animate the Vertices (because with your method you don't move the object, only the vertices) directly in the Edit Mode with the AnimAll Add-on. But this will only playback properly in Object Mode.

I didn't know about animall, @Leon95 edited the answer in a much better shape and also added about it... I'll have to check it!

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


text:
Synchronizing animation with a beat
I want to make a music video for a techno song with a constant beat. I want to simulate strobe lights that flash in time with the beat (one set of lamps for the kicks, one for the snare etc).
Q what is the easiest, most efficient and most accurate way to do this? Bear in mind the song is several minutes long so doing it all by hand would be very time consuming. I'm not afraid to get my hands dirty with programming (though I have not done that with Blender before). Any help is much appreciated.
Thanks

Do you have drum midi track?  Have a look at http://blender.stackexchange.com/a/47608/15543 If you  know what frequency range roundabouts of the drums you can drive from baked fcurves. Have some (very) test code for making fcurves (and hence animating) from drum midi tracks, that I could push to a branch.

It is pretty easy with animation nodes. Search for music driven animation nodes in google - there are some great tutorials

In the current development of my own Blender AMV, I answered a similar question in another post. Have a look and see if this helps.
Tips for creating an animated music video?
Read through it before continuing to read this answer.
Once you map out your song with the drum beat and place it in Blender, you can scrub through your drum track and manually animate the lights. I know that you can keyframe their values, meaning you won't spend as much time animating each light.
And an idea to go with that is to copy and paste keyframes in the dope sheet. That will save you some time instead of manually keying each value.
Be aware that your framerate must match the beats per minute of your song, otherwise syncing will be off and you'll end up with a headache. To avoid this problem, determine the BPM of your song here. https://getsongbpm.com/tools/audio
Once you have the BPM, calculate the frames per beat here. https://www.vjamm.com/support_av_bpm.php%3Flang=en.html
Adjust the value of the framerate until the frames per beat is a whole number. Then you can adjust your framerate in Blender to match with the one shown when you determined your frames per beat.
From there, start animating!
Hope this helps!

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


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Generate rig from mesh
Is it possible to generate a rig based on a mesh? I'm thinking something simple like having one bone per edge.
I'm going to look into scripting it I guess but if someone did something similar already it may save me the trouble.

Thanks to both of you. It seems you have the same acquaintances :). Blender 2.49, that's a scary thought. But I'll look into it and the script, if I can lay my hands on it, would probably help.

EDIT: Armature from Edge Loop https://blenderartists.org/t/armature-from-edge-loops/515611/12 last update 2012, but liero was always very kind to help, you can try to ask. Previously posted unfolding (armature from faces) https://raw.githubusercontent.com/addam/Export-Paper-Model-from-Blender/master/object_convert_to_armature.py (2.79) or extended https://blenderartists.org/t/unfold-transition/586992 (2.79 / 2.80) generates bones that expects rig these faces (not other mesh).

Add Skin Modifier to your Mesh (edge structure)
Press "Create Armature"

It's noteworthy, that the mesh is converted to an armature. It has to duplicated, otherwise the original will be gone.

If you have one connected edge loop, you can use this script.

The mesh object has to be selected before executing the script.
import bpy

def CreateBoneChainFromVertices():
    obj = bpy.context.active_object
    if (None == obj):
        return

    if (obj.type != 'MESH'):
        return
    bpy.ops.object.mode_set(mode='OBJECT')

    edgesA = []
    edgesB = []
    for i in range(len(obj.data.edges)):
        ver = obj.data.edges[i].vertices
        edgesA.append(ver[0])
        edgesB.append(ver[1])

    chain = []
    chain.append(edgesA[0])
    while(True):
        current = chain[len(chain)-1]
        if current in edgesA:
            idx = edgesA.index(current)
            next = edgesB[idx]
            del edgesA[idx]
            del edgesB[idx]
            chain.append(next)
        elif current in edgesB:
            idx = edgesB.index(current)
            next = edgesA[idx]
            del edgesA[idx]
            del edgesB[idx]
            chain.append(next)
        else:
            if (chain[0] in edgesA) or (chain[0] in edgesB):
                chain = list(reversed(chain))
            else:
                break

    amt = bpy.data.armatures.new(obj.name + "_vBones")
    rig = bpy.data.objects.new(obj.name + '_vRig', amt)
    bpy.context.collection.objects.link(rig)
    bpy.context.view_layer.objects.active = rig
    bpy.context.view_layer.update()

    print(chain, "here we go")
    bpy.ops.object.editmode_toggle()
    for i in range(0, len(chain) - 1):
        bone = amt.edit_bones.new(str(i + 1))
        bone.head = obj.data.vertices[chain[i]].co
        bone.tail = obj.data.vertices[chain[i + 1]].co
    for i in range(0, len(amt.edit_bones) - 1):
        amt.edit_bones[i + 1].parent = amt.edit_bones[i]
        amt.edit_bones[i + 1].use_connect = True
    bpy.ops.object.editmode_toggle()

CreateBoneChainFromVertices()

Thank you so much for such a quick response and fix for 2.8. I just noticed the Skin modifier option, that also works for fork (like hand with fingers). Sorry.

Thanks @Leander, I'll study this

@Leander thanks a million for your example. It prompted me to actually write something to do the job automatically. There may be a gravity rig add-on before long.

@Kiskit Cool, please update me if there is an (open-source) github or blender.se post.

I'm not sure yet how I'm going to release it, but given how you took time to help me with code, I won't ask you for money if you want it ;). Also you're in the thanks on the youtube video's description. Look for "Gravity Rig Blender add-on introduction".

Thanks, looks cool, but I won't use it anytime soon.

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


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OSM (Open Street maps) on Blender plane
I am looking to take OSM data of roads and display it on a 2D plane. (3D objects will come later).
I have used FME to convert the data to SVG, But when I import it I get a lot of curves, but they are not visible. Probably need to to do something simple (give a a material?)
Anyway here is what the SVG file looks like: (data is in Lat Lon). The importer says this works fine. And I can view the SVG data in Chrome.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-flat.dtd">
<svg xmlns="http://www.w3.org/2000/svg"  viewBox="-3.59534e-005 -3.59534e-005 0.00294818 0.00381678"><g xmlns:fme="http://www.safe.com/fme" fill="none" stroke="red" stroke-width="0.000000359533915" transform="translate(0,0.00374488) scale(1, -1)">
<g id="way" >
<path fme:id="-2096" fme:visible="true" d="M 0.00267276,0.00303538 l -0.00014045,-0.000209472 -0.000138128,-0.000195737 -0.000145093,-0.000203464 -0.000106788,-0.000186295 "/>
<path fme:id="-2094" fme:visible="true" d="M 0.00186222,0.00192878 l 9.55227e-005,-8.6277e-007 "/>
<path fme:id="-2092" fme:visible="true" d="M 0.00181594,0.00192882 l -0.000128648,1.66573e-006 "/>
<path fme:id="-2090" fme:visible="true" d="M 0.00202719,0.0030487 l 4.84211e-006,-0.000327528 6.96445e-006,-0.000366579 2.32148e-006,-0.000218918 2.32148e-006,-0.000115898 "/>
<path fme:id="-2088" fme:visible="true" d="M 0.00153523,0.00321051 l -9.28593e-006,0.000169981 4.64297e-006,0.000109028 3.5983e-005,7.55467e-005 6.96445e-005,6.95373e-005 7.42874e-005,4.72166e-005 9.63415e-005,2.40375e-005 0.000117235,1.71697e-006 0.00010911,-1.11603e-005 0.000128842,-2.57545e-005 "/>
<path fme:id="-2086" fme:visible="true" d="M 0.00150738,0.00292721 l 1.04467e-005,0.00011418 "/>
<path fme:id="-2084" fme:visible="true" d="M 0.00176506,0.00288686 l -4.64296e-005,5.40851e-005 -0.000121878,0.000139076 "/>
<path fme:id="-2082" fme:visible="true" d="M 0.00160836,0.00281818 l 9.98237e-005,2.57548e-006 "/>
<path fme:id="-2080" fme:visible="true" d="M 0.00158747,0.00252801 l 7.89304e-005,3.34815e-005 6.50015e-005,4.97929e-005 4.75904e-005,5.06514e-005 2.6697e-005,7.98402e-005 "/>
<path fme:id="-2078" fme:visible="true" d="M 0.00151402,0.00275113 l -4.92461e-006,-0.000146906 7.38691e-006,-4.97781e-005 "/>
<path fme:id="-2076" fme:visible="true" d="M 0.000956723,0.00265704 l 5.58122e-005,4.00652e-005 0.000137068,8.07375e-005 0.000168257,5.15991e-005 "/>
<path fme:id="-2074" fme:visible="true" d="M 0.000943283,0.00225656 l 0.000206612,7.38312e-005 0.00021938,7.81236e-005 "/>
<path fme:id="-2072" fme:visible="true" d="M 0.000316483,0.000195263 l 8.12519e-005,-3.86339e-005 9.51808e-005,-2.66145e-005 0.000114913,-6.86826e-006 0.000113753,8.58532e-006 0.000314561,4.0351e-005 "/>

Looks from the data the svg curves will be on small scale rather than too large.  (all < 0.003) The addon https://github.com/vvoovv/blender-geo will generate roads (as a mesh) straight from the OSM file, which can be converted to curves easilly.


text:
How to add ambient light when using cycles render?
There seems to be an "environment lighting" setting when in Blender render, but there does not seem to be anything equivalent in Cycles.
Currently, the rendering of my scene just looks grey, even though some objects I have coloured white, and I am hoping adding ambient light will fix that.

In cycles the world/environment emits light by default, so just making the world background color white will illuminate things more. Note that this will likely result in a very uniform, washed-out sort of look, since everything is illuminated the same amount from every direction.

In a typical photographic situation, you would add fill light from a soft / broad source. This could be above your object in question, or a fill light lower down and in front. Using an area light allows you to get the softer breadth required to avoid hard shadows.
Light ratios also tend to be completely whacked unless you are using a viewing transform that emulates a more photographic range of light as well, typically over-crunching the shadow data, and horrifically crimping the highlight data that is in an image. If you are interested, have a look at this question.

I believe HDR lighting is what you're looking for. Using HDR lighting will simulate light coming from all directions, similar to how things are lit when sitting outside under the sun (or on a cloudy day, depending on the HDR image you use). Here are some free HDR images you can use. I would recommend starting with one that has the sky visible in the image.
Another great resource is Andrew Price's Pro-Lighting: Skies add-on. The free demo is here, and his tutorial for how to use HDR lighting (with or without his add-on) is here.

free demo is a broken link

Google is your friend. There’s plenty of info given in the post to find it. Edit the answer and update the link if you’d like.

FWIW: Terminology: "HDR" simply means "High Dynamic Range". An "HDR image" (HDRi) is simply a format for storing an image with High Dynamic Range. "Simulate light coming from all directions with an image" is an "Environment Map". Despite Andrew Price's (and others) usage, it is ..illogical.. to conflate the two, and call use of an HDR Image as an Environment Map "HDR Lighting". "HDRi Environment" would be clearer terminology.

Properties panel -> World -> Surface panel -> select Surface Background and you can set the color there.
In Blender 2.80 it looks like this:


text:
How to export a transparent clip?
In my node editor I have a small movie clip with a green screen. I keyframed it to get rid of the green screen and I am using a transparent background image. I have realized that most of the video formats don't support transparent backgrounds, so I am trying to just render it frame by frame. However, when I use a format that should support transparency, like png, the pictures just come out with a brown or black background. My goal is to overdrop the clip on another video I have. How do I export this clip with a transparent background? Thanks for any help!

Nevermind, figured it out. Turns out I was rendering with the RGB preset instead of RGBA.
EDIT: Expanding upon my explanation: I was getting a brown background whenever I didn't check "use alpha" on my output node. So I checked that and it solved that problem. I was getting a black background on my render images because of my answer stated above. On your render options in the properties tab, right next to the type of file output you have 3 options: BW, RGB, RGBA. I was rendering my images with the RGB preset, which stands for Red Green Blue, instead of RGBA which stands for Red Green Blue Alpha. So it makes sense that it previously wasn't rendering my alpha background.

please expand on your answer a bit, to make it more useful to future viewers.


text:
Grow tree and animate
I'm trying to build a tree using multiple tiers (circle, extrude, scale), like a pine tree and their layers, and then animate it.  Any suggestions on how to proceed??
Thanks.

https://www.youtube.com/watch?v=8GKes2FYy0E&list=PL0RtAku-eLdMb4gFVgLgJxgC8BkxpcyMR&index=10
https://www.youtube.com/watch?v=svErsjEJEo8&list=PL0RtAku-eLdMb4gFVgLgJxgC8BkxpcyMR&index=17

You can apply the array modifier to stack the shapes you described on top of each other. And, then, use the curve modifier (but don't apply it) to bend the stack in order to make an animation of the wind blowing on the tree like this:

Now, just add the top, the trunk and setup the materials:


text:
Can I use the weigh paint information as color vertex information?
I've came up with a question regarding weight painting and color vertex data.
So this is the explanation to my question:
I would like to use the gradient I created as weight paint to create a mask with B&W information and use it in the node editor like when I create a color vertex data and re use it with the atribute COL in the node editor.

I created a mask manually to show what I ideally want.
Is there a way? thanks a lot in advance!

Well a few minutes after I posted the question here, I sent the question into a Slack Group and Julian Perez (@julper) found this great addon that fits exactly to what I was needing.
I will share what he found with you.
The addon is called Weight-and-Color

Seems it requires to be updated for 2.8+ unfortunately


text:
What does this icon mean - circle next to a child in blender
I would like to know what the circle icon next to Body_M_Georndr.005 means and why it is not next to part_Kidney_Right since they are both children of the same parent

Circle next to "Body_M_Georndr.005" shows that material is assigned to that mesh. It's not visible on the image if they are children of the same parent but assigning materials isn't related to that.

That is the icon of a Material datablock, it means there is a material assigned directly to the mesh data, as opposed to the object itself.
When creating or editing Material Slots you have two options when assigning a material, it can be either assigned to the Object or the Object Data.
When assigned to the object, several object clones or instances of that object (while sharing the same geometry or mesh data) can have different materials regardless, but if the material is assigned to the Object Data all instances will forcefully have that same material.
Each materials assigned to Object Data will display one additional icon to the side of the data it is bound to in the Outliner, other materials show up below.


text:
Keyframes in Dope Sheet Less Than Second
I would like to know if it's possible to save bone structure how the figure should be between seconds. That green line only locks to seconds like 1, 2, 3 and so on.. but the character moves the head faster, how can I save it between the seconds if it's even possible.

Is it possible to do at 3.5 or even more accurate, like 3.12 or something like that?
Thanks in advance.

First off you are viewing frames, not seconds. (You can switch to view seconds, but that is a different matter). Yes you can keyframe sub frame, just turn off the auto snap.


text:
Blender needs more CPU power than before
I haven't done much I only moved the Camera, the smoke meshes and increased the size of the smoke domain. And now the render needs much more time than before.
And what can I do before the render that it doesn't need so much time.

Rendering smoke takes time.  Keep in mind that rendering more smoke from a bigger domain will necessarily take more time than a smaller domain.

Possible duplicate of https://blender.stackexchange.com/questions/79117/why-does-fire-take-so-long-to-render?rq=1

Are you simply asking it to do more work?


text:
Blender 2.79 doesn't detect my AMD GPU 270X
As described in the title Blender doesn't detect my GPU, it's an AMD Readeon R9 270x.
I tried to install an older version of CCC but that didn't work too.
There is one Strange thing at "OpenGl-Version" in the second column there is written: "Nicht Verfügbar"->not available.
I attached some screen shots shot at the Amd Catalyst Control Center i hope that will help.


text:
Loading UV map into UV/Image Editor
Its probably a very stupid question but i dont know the answer

On the right you can see a UV map and probably i am too stupid to find the button that loads the uv map into the UV/Image editor.

Just enter Edit Mode

you should also load an image


text:
How would I subdivide a triangular face?
I would like to subdivide a triangular face.
When I select the face in Edit Mode and click subdivide, I don't see any subdivisions. I have measurements visible and new numbers appear but no corresponding subdivisions.

Related: https://blender.stackexchange.com/questions/80646/how-can-i-sub-divide-an-equilateral-triangle-into-many-smaller-equilateral-trian

You don't see this? http://i.imgur.com/VMc6VNn.png

Is the face actually triangular? How many vertices does it have before subdiv?

Exactly how did the triangular face come to be? Is this a newly created face, or is it a face in an already existing mesh? And what method were you using to try to subdivide it?

This is a face in an existing mesh with 3 vertices.  I then select Subdivide from the Tools palette with one straight cut.

Hi Greg - in response to the image. No, I don't see the subdivisions.  The number of labels edge info labels increase but no subdivisions appear.

This may be a case where I need to start over from scratch.  I am also finding that if I select a face, do a Shift-S and place the Cursor to the Selected face, that any primitive added cannot be selected after it is created.  It is certainly visible, but cannot be selected in object or edit mode.  Primitives are not  appearing in the tree view.  I'm wondering if this is a corrupt file.

"Primitives are not appearing in the tree view." if adding them is done just after snapping cursor to the face then it's most likely done in Edit mode and no new objects will appear in the Outliner as all added meshes will be part of edited object. "The number of labels edge info labels " can you include a screenshot before and after subdivision?


text:
Dynamic Paint and Wave modifier looks different in the Render and Viewport
I have this animation of a coin falling into a smartphone's screen / water, and creating ripples as visible below in this viewport screenshot:

The ripples on the surface are a mix of Dynamic Paint and Wave Modifier (based on a Gleb Alexandrov tutorial).
When I render, the ripples disappear:

What causes this?

Weird, i tested your file, changing nothing. I rendered multiple times and for first ones some frames didn't have any waves, while later re-renders worked perfectly (I deleted cache before every render)... Me do not like that.

What version of Blender are you using?

I am using version 2.90 - any clues as why this is happening? Will try with the latest version now that I've just downloaded.

found that https://developer.blender.org/T59997 about 2.8, but i tested in 2.9 and found that it is also happening.

Dynamic paint apparently needs baking to work in render in 2.9.

Baked simulation:

Here: https://developer.blender.org/T59997  the issue is pointed in Blender 2.8, but it still marked as a known issue.
Edit:
Adding here that in 3.0 there is no need to bake.


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All my objects became non-selectable
All the objects in my scene (around 2'000) have the selection feature disabled all of a sudden (v.2.78):

I can drag the mouse down to reselect them, but the computer lags, and a lot of them don't get highlighted when I do this.
I looked at this and this, but I cannot find out how to make the scripts work.
Is there a quick and dirty way to make all the objects in the scene selectable again?

One option is to use shortcuts in the Outliner editor - V for visibility of the objects, S - for selectability and R for renderability. Note that mouse has to be over the Outliner editor while using the shortcuts.

Open the Outliner. You need to point to Blender which objects' settings you want to edit. As they are unselectable, press A which will create blue overlay over the objects and will select them for the Outliner actions.
Press the shortcut for desired operation, in the case of the question - S for selectability.

Note that this is toggle, so it will invert current state of the adjacent property; if object-A was unselectable and object-B was selectable, objectA will become selectable and objectB the other way around.

The S shortcut toggles selection on or off even if the object is deselected when I try this. If I have all the even object numbers selected and the odd numbers not selected, it will switch. I am trying to select all or deselect all.

@MicroMachine if the property is toggled then the object is selected (in Outliner). Toggling is indeed the downside of this method which is mentioned in the last paragraph of the answer; meanwhile the addon from the answer you linked works just perfectly thanks to Pink vertex.

While the addon in the first linked answer works, it has a main flaw, it either toggles or sets the selectability of the selected objects, so you can easily disable the selectability but you can't enable it unless you can select the object/s to start with.
The other answer works as expected, which is it toggles every object that is selected in the outliner. While selecting all is easy enough, that may include objects you don't want to toggle. This is really just the same result as the answer by WKG which has always been in blender.
For a simple brute force solution that just enables the three options shown in the outliner for every object -
import bpy

for o in bpy.data.objects:
    o.hide_select = False
    o.hide_render = False
    o.hide = False

You can easily adjust that to disable them again or just alter one of the options. You could change bpy.data.objects to bpy.context.selected_objects if you wanted to disable a selection of objects.


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Can you easily export a .blend to a previous version of Blender?
I have 2 versions of Blender, 2.79 and 2.9.
I edited a .blend file that was made in 2.79 today in 2.9, then saved.
Now, I cannot open it in 2.79 anymore (it just crashes Blender). However, there are plugins in the 2.79 version that I haven't yet installed, or might not exist in 2.9. And I have to deliver some files.
I now that all Adobe apps allow you to export documents to a previous version if you need, but I couldn't find anything about Blender. I would prefer not to have to redo textures, etc.
Can I export the file from 2.9 to 2.79 easily?

TLDR: Is it possible? Yes.  Is it easy? It's not one-click.
Each release of Blender may introduce new features that are not backward compatible with older versions. As a result, attempting to open a .blend file created in a higher version of Blender in a lower version can lead to compatibility issues. While Blender will make an effort to open .blend files from any version, the success rate is not very high. With the advent of collections instead of scenes, the scene will open empty. So going from 2.9 to 2.79 directly will not fly.
However, if you are willing to jump through some hoops, you can extract things of interest out of those files with the Link/Append functions under File Menu.
Just make sure to choose the right object. You will also need to make sure that modifiers and nodes that were added since were not used in the object you are trying to back-port.
I successfully yanked one of my characters out of a 2.9 version file and got it running on 2.79, but there was some fiddling I had to do and I wasn't doing anything too special rigging wise. Also remember that you must use Cycles in 2.79, Blender render materials are not compatible with Cycles/EEVEE.

Life saver! Append, of course! Why didn't I think of it before! Thank you, that solved it!

Glad I could be of help.  If things really go sideways, you can export it as a .FBX and re-assemble it.


text:
I can see the seam of meshes in rendered image
I'm trying to render light bulbs, but I'm facing a problem in subdivision-surface modifier.
I applied Subsurf modifier for each glass of bulb with UV sphere and Solidify modifier after it.
I chose 4 for Subsurf modifier for each glass of bulbs but it showed the seam of mesh of bulbs like below.

So I've tried giving more divisions(6) and ended up with Out of memory error of CUDA.
I tried it with only one bulb and it looks much better.

Is this normal behavior? or Did I do something wrong?
Giving more subdivisions for all the bulbs are not feasible with GPU rendering.
Please share any techniques, if you know, to make the bulbs more smooth.

can you share the blend file?

Why not just use smooth shading?

pycoder has it right, you have flat shading enabled, open your tools panel on the left (hit t) and click 'Smooth', subsurf level 2, or 3 should be fine.

Thank you, @pycoder. Smooth just works for me :D. This looks very fundamental BTW. Sorry for the question like this.

You might also want to reconsider your topology from uv sphere style poles, to a polysphere (basically a subdivided cube shrinkwrapped around a sphere) to avoid pinching at the poles.


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SyntaxError when trying to launch Blender 2.78 with Python 3.6
i just did a fresh install of Blender 2.78 (32 bits) on windows 10, i also have only one version of Python 3.6 (32 bits) installed and i can't launch Blender, i get this error message :
Failed to import the site module
Traceback (most recent call last):
  File "C:\Python36\Lib\site.py", line 73, in <module>
    import os
  File "C:\Python36\Lib\os.py", line 652, in <module>
    from _collections_abc import MutableMapping
  File "C:\Python36\Lib\_collections_abc.py", line 64
    async def _ag(): yield
                ^
SyntaxError: 'yield' inside async function

This is my PATH variable :
Path= ... C:\Python36\;C:\Python36\Scripts

and my Pythonpath variable :
PYTHONPATH=C:\Python36\Lib


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How do I recover a blender file that looks like a new file when I open it?
I have been working on a file for a while and I know I saved it before I closed it, but when I opened it again it says I´ve opened it but it looks like a new file. With the cube and the light etc. I´ve tried to open it in several different ways but it always just looks like a new file. Completely gone. What do I do?

If you see the old objects in the outliner, you could try to append them to a (really) new file. The broken file may be damaged beyond repair, but the new one will get all objects from the other and you can continue your work on it.

I tried recovering the autosave, its still just the cube and the lamp. And there are none of my objects in the outliner. I dont get what happened


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Show/Hide an Input Field based on a conditional when making an Addon
I am writing a Blender Add-on which takes properties from configuration file and generates a tree based on the customization. The Add-On allows tweaking of certain properties, most notably whether the tree is monopodial (one canopy) or sympodial (multiple canopies).
If the tree is sympodial, I want the user to be able to select how many canopies are present in the Add-On. If the tree is monopodial, I want the fields to either be hidden or greyed out/locked for editing.
I've tried something like
row = box.row()
row.prop(scn, "Tree_Form")
if (tree_form == "Sympodial")
    row = box.row()
    row.prop(scn, "Num_Canopies")

But I haven't had success. Admittedly, I am a complete novice to Python and Blender Add-Ons in general.

Based on guesswork re your code snippet, you want something like if(scn.Tree_Form == "Sympodial"):  Don't forget the colon  after the if statement.

Try this:
row = box.row()
row.prop(scn, "Tree_Form")
if scn.Tree_Form == "Sympodial": # the ':' is required
    row = box.row()
    row.prop(scn, "Num_Canopies")

Wow. How did I not look to see that I needed a colon at the end? Thanks so much!

I myself, was stuck on .props and such.


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How are blender UVs stored in relation to individual vertices?
I recently decided to make  a binary exporter to load into a game engine I am also writing, but I'm very much stuck on blender UVs. I understand that the UVs have to for loop indices because of hard edges, but I have no idea how to pair the UV up with their respective vertices.
What is the relationship between a UV coordinate and a vertex in blender? I would like to be able to remove the duplicate vertice/UV pairs to cut down on buffer data in my program (which I would imagine would save a LOT of data for a handful of complex models), but I can't seem to pair the two together.
I can see how loop indices pair with vertices in the polygons class and via the vertex_index property of loop indices, but I have no idea how to relate these to the appropriate uv_layers data. Any help would be greatly appreciated; thanks for your time!

The UVs and Vcols (vertex Colors) have the same logic of "per vertex in a face" order, flated in a simple sequence.

You have the polygon vertex indices and vertices list, so it can be deduces from here. Simple and very useful. More so, if u actually generate the mesh data and not read from an object.
You can access the mesh loops (the very rule of vert per face etc) to read what contains the vert index / uv. This should be done probably with foreach_get/set function that is more efficient.

Let's see var 1, as you actually seam to know these but just miss the relation poly/vert index
(note that I create list of indices of the uv/vcol and verts, for precise coords etc you can further use them to read or write to actual data):
creating perPolygon and perVertex lists of lists
like [[1, 3],[2, 5], [6, 8, 9]..] that correspond to the polygon / vertex list
    perPoly = []
    perVert = []    # best variable name yet :D

    if Object is not None and getattr(Object, 'type', '') == "MESH":
        # these are the poly vertex indices (as in the vert list)
        polyIndices = [p.vertices for p in Object.data.polygons]

        # create an list with empty lists for all verts
        perVert = [ [] for i in range(len(Object.data.vertices))]

        increment = 0
        for poly in polyIndices:
            lenP = len(poly)

            perPoly.append(i + increment for i in range(lenP))
            for i, vi in enumerate(poly): perVert[vi].append(i + increment)

            increment += lenP

Note that I have not even read the uv (or vcol) data, if any. So you can use this in the very process of creating your own mesh or where there is no uv/vcol yet.
perVert / perPoly contain indication to positions in the ...uv_layers[0].data

the opposite, creating a list that parallels the uv list but contains the vertex index goes by flattening the polygon indices (polygon.vertices) list
Basically, that is the way the uv list is done..
# explicit
flatVertsLikeUVs = []
for poly in Object.data.polygons:
    for i in poly.vertices:
        flatVertsLikeUVs.append(i)

or using chain, same stuff..
from itertools import chain

flatVertsLikeUVs = list( chain.from_iterable([p.vertices for p in Object.data.polygons]) )

an example:
uvs = Object.data.uv_layers[0].data
matchingVertIndex = list(chain.from_iterable(polyIndices))

# example, matching list of uv coord and 3dVert coord:
uvs_XY = [i.uv for i in Object.data.uv_layers[0].data]
vertXYZ= [v.co for v in Object.data.vertices]

matchingVertIndex = list(chain.from_iterable([p.vertices for p in Object.data.polygons]))
# and now, the coord to pair with uv coord:
matchingVertsCoord = [vertsXYZ[i] for i in matchingVertIndex]

-
ps:
getting the mesh loop data/ uv layers with another option, but logic is the same:
you may wanna look here for populating the list with fromeach get / set
http://blenderartists.org/forum/showthread.php?391847-Efficient-copying-of-vertex-coords-to-and-from-numpy-arrays&highlight=numpy
you can skip the numpy part and just populate a previously created list, (like the perVert above).

I appreciate the time you took to help with this, and your sense of humor. I think I worded my question poorly. I have no issues obtaining the data for each of these items, but I'm not sure what uv_layers.active.data[x] would translate to in loops or loop indices. Once I understand that relationship, I can sort the rest of everything else out. I'm not really worried about exporter efficiency, as I have 0 python skills; I just want the file to be efficient for the engine.

the perVert/perPoly are a list of indices (in the same order as vert/poly lists, so you can zip them) that  reference the uv_layers[0].data list.   I'll try to add an extra visual explanation.

This is exactly what I was confused about. Thank you so much! Also learned some new Python tricks looking through your code as well!

Can't you just use the mesh's .loops attribute?


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Numeric values of camera angles while tracking
When tracking, for example the origin, and moving the camera in
space, the camera angles are clearly not zero. Still, in the
parameter display the 'Transform/Rotation' is displayed as (0,0,0).
How is this possible?

How can I get the real camera angles?

You have a Track to constraint on the camera (it's what I see), or a parent relation maybe.
The Rotation in the properties panel does not take in account the constraints or parenting effects, so it shows 0.
You can enter bpy.context.scene.camera.matrix_world.to_euler() in the console and it should give you the real orientation of the camera.


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Camera View Coordinates and Z-depth values
In my understanding the z-coordinate of the camera's view looks at the observer, away from the image plane. This is consistent with the camera angles of (0, 0, 0)
while the camera looks down and the camera's z-axis points in the same direction
as the global z-axis.
In the rendered image window, when I click on a point in the image, I am
getting a positive z-coordinate for an object in front of the camera. Should that
not be negative?

The answer by cegation contains error. I've done experiments using Z depth for point cloud alignments, and quite sure that the camera direction is +Z axis. Thus, from his diagram, Z and Y axis should be negated!

It is though. I verified this with experiments where I aligned point cloud generated from multiple cameras globally. The intrinsic and extrinsic matrices only made sense when I treat depth along Z axis. I'm pretty sure of this.

I'm not confusing those two. They CAN be different, but they ARE same, according to my experiment. (i.e. Z depth and local Z axis is same in blender) I won't argue anymore, but please try some experiments to figure that out dude.


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Lamps don't seem to give off light in object mode
I played with the lamps earlier in the sculpt and they worked as expected. Tilt the light and the shadows followed accordingly. Then I wanted to get rid of it and I assume I clicked something I shouldn't have as now the light only shows in rendering. The issue follows me to new files and after uninstalling and reinstalling the program which seems odd. Is there a setting or option that I inadvertently clicked or did I just break it somehow?

A friend found out what happened- apparently the viewport shading switched on me!
 I switched it to material and it was as what I was looking for.


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Python: Obtaining Object Contour Pixels
I would like to obtain the pixel coordinates of an object's outline in the currently-rendered scene, using the bpy module.
I found this, which is related, but I'm still not sure how to do it.
Has anyone had experience with something similar?

You should have a look at this and this.

@sambler thanks! The second link was especially useful, assuming I understand it correctly (I've yet to test).

Edited - refined answer that only requires numpy
To find the outline pixels of an object:

Make sure it has a separate object ID than other objects.

Check the Object ID pass in the scene tab of the properties panel.

Replicate this node setup in your compositor and render your scene.

Run this script:
import bpy
import numpy as np

S = bpy.context.scene

# Read render settings - image size
width  = int( S.render.resolution_x * S.render.resolution_percentage / 100 )
height = int( S.render.resolution_y * S.render.resolution_percentage / 100 )
depth  = 4 # RGBA

img = list( bpy.data.images['Viewer Node'].pixels )      # Read viewer node

# Reshape into 2D RGBA matrix, then Keep only R value for each pixel to convert to grayscale
img = np.array( img ).reshape( [height, width, depth] )[:,:,0]

# Find edge pixel coordinates. Each row has the X and Y values of an edge pixel
edgePixelCoordinates = np.array( img.nonzero() ).T

print( edgePixelCoordinates )

The print statement above will spew out a preview of the full array. Looks like this with the outline above:
[[128 511]
 [128 512]
 [128 513]
 ...,
 [379 531]
 [379 532]
 [379 533]]

Original answer with OpenCV

The code below will do most of the heavy lifting, though it isn't trivial to implement, and uses 3rd party python modules (mainly numpy and opencv). It also assumes you have a different object index for each object in your scene, and a node setup that includes an object ID mask plugged into the viewer node in your compositor.
What Isn't covered here:

How to install 3rd party modules in blender's python. See this answer to solve that.
How to automatically set the object index on the object ID mask node to that active object (that's a fairly easy step to add).

What is covered here:

How to find the outline of a mask using openCV.
How to find the pixel coordinates of the outline.
How to generate a blender image containing the outline (wasn't required but is useful for debugging).

To use this script, set a different pass index to each object, or at least a different pass to the object of interest compared to other objects. Also, in the scene tab of the properties panel, add the Object Index render pass. In the compositor, Add an ID Mask node and connect it to the IndexOB render layers output, then connect the ID Mask's output to a viewer node. Render the scene once, and you're good to go! Run the script and you'll be able to see the outline in a new (or existing) image called 'edges' by default.
The script stores pixel coordinates as an array of XY pairs. The first 10 pixels from the contour above look like this:
>>> edgePixelCoordinates[0:10]
array([[128, 527],
       [128, 528],
       [128, 529],
       [129, 527],
       [129, 529],
       [129, 538],
       [129, 539],
       [129, 540],
       [130, 527],
       [130, 528]], dtype=int64)

Here's the code:
import bpy
import numpy as np
import cv2

S = bpy.context.scene

# Read render settings - image size
width  = int( S.render.resolution_x * S.render.resolution_percentage / 100 )
height = int( S.render.resolution_y * S.render.resolution_percentage / 100 )
depth  = 4 # RGBA

img = bpy.data.images['Viewer Node'].pixels             # Read viewer node
img = np.array( img ).reshape( [height, width, depth] ) # Reshape to 2D RGBA matrix

# use 1 color channel (=grayscale) and convert from float to 8bit int pixel values
img8bit = np.array( img[:,:,0] * 255, dtype = 'uint8' )

# Use the canny filter to find edges
edges = cv2.Canny( img8bit, 10, 20 )

# Find edge pixel coordinates. Each row has the X and Y values of an edge pixel
edgePixelCoordinates = np.array( edges.nonzero() ).T

## Add outline as image in blender
# Generate an RGBA image from the 8bit outline image
edgesRGB = np.zeros((height,width,4), 'uint8')
for i in range(3):
    edgesRGB[..., i] = edges
edgesRGB[..., 3] = np.ones((height,width))

# Flatten image matrix to a 1D vector - the way images are stored in blender
blEdges = edgesRGB.ravel()

# Create new blender image to store outline, or assign to existing one
outlineImageName = 'edges'
edgesBlImage     = None
if 'edges' in bpy.data.images:
    edgesBlImage = bpy.data.images[ outlineImageName]
else:
    edgesBlImage = bpy.data.images.new( outlineImageName, width, height )

imNew.pixels = blEdges

This is a beautifully detailed answer. Thanks!

First, I can obtain all of the object's vertex pixel locations as done here.
Next—though this may not be the most efficient method—I can determine contour pixels merely by processing the exported image data. I set the first and last vertex pixels in a row to 1, as well as any vertex pixels that are followed or preceded by non-vertex pixels. I set the rest of the pixels in the row to 0.
By repeating this for all pixel-rows in the exported image data, I should be able to obtain an outline.

You could use the objectID to get a mask of the object? and scan the pixels to get the outline. Kinda like this answer.


text:
Export bones' ends trajectory - xyz coordinates
I am new to Blender and python. In an effort to learn, I would like to write a small script that exports the root and head coordinates to a csv file for each frame.
Can somebody help me with this please?


text:
How to Rotate and Animate object every other angle?
I am trying to create an animation by rotating an object every 137.5 degrees on its origin (at 550 RPM with 24 frames/sec) and taking those frames to create a video.
How would I implement this?

Driver Approach
You can type a driver directly into field using #.  Typing
#radians(137.5 * frame)

into the rotation.z field of an object will make it spin at 550rpm at 24 fps.
In the added file I've set up two custom properties "spin", how many degrees per frame, and "rpm".

The rotor rotates
radians(spin * frame)

and the rpm is calculated via a driver by
rpm = fps * spin * 60/360

Original post: https://blenderartists.org/forum/showthread.php?229688-Helicopter-Rotor&p=1937512&viewfull=1#post1937512


text:
Pixels in Cycles render
I'd created glass bottle filled with corks, rendered it in Cycles and I've got low resolution pixeled render. It does not look like the problem with fireflames everybody writes about: number of samples and other things does not help. :(
Any ideas?

do you have a displacement / bump map on the cork? What happens if you make a border render of that region. (ctrl+B, lets you draw a rectangle to delimit the area in question). Set the render solution from 50% to 100% or  200% - as a test

What resolution (image size) are you rendering?


text:
What's the relation between Cycles' sampling pattern and the pixel filter?
In Cycles' render settings, there is a setting for a sampling pattern (default Sobol), and there is a setting for a pixel filter (default Gaussian).

What is the link between these settings?

More specifically, this is my understanding of what the two settings mean:

Sampling pattern: indicates a pattern of points within a pixel where rays will be cast into the scene
Pixel filter: used to filter the rendered image (post-processing, if you will), much like a Gaussian blur in Photoshop; this effectively adds to every pixel some contributions from neighboring pixels

I hope my understanding about these is more or less correct.
Now my question, more precisely, is:

Could one use a sampling pattern that goes outside of the pixel boundaries to combine the sampling pattern and filtering into a single procedure?

Simple Answere

What is the link between these settings?

The Pixel Filter randomly changes the coordinte of every sample with the given distribution, meaning for example: When the Sobol Sampling Pattern samples near the edge of the pixel, the neighbouring pixel might be lit instead with a rather high probability. This is used to get rid of aliasing on the sharp edge of very bright objects, like mesh lights.
Look at these examples with a mesh light with a strength of 100. You can see the noisy Gauss distributed white dots during the whole sampling process.
Gauss with width of 0:

Gauss with width of 2:

Gauss with width of 10:

With more samples the last two would both result in a smooth image. The higher the width of the Gauss the less antialiasing you get, but at the cost of loosing some sharpness.

Could one use a sampling pattern that goes outside of the pixel boundaries to combine the sampling pattern and filtering into a single procedure?

Actually, this is a not a bad idea, but I never heard of any renderer doing this. Convoluting the Sampling Pattern with the Pixel Filter and using the resulting function as the new Sampling Pattern should result a render that converges to the same image.
This is however not desired probably because being able to separately choose these two functions rather than from a huge list of all possible convolutions is better. And the common Pixel Filter functions are used in other type of renderers, where sampling is done over the whole image rather than pixel-by-pixel, and one sample really lits multiple pixels, which is not stochastically sampled but fully calculated, like LuxRender.
Mathematical Explanation
First Possibility
Given the i-th columns k-th pixel indexed from 0, the Sobol Sampling Pattern gives a uniform pseudo random 2D vector (x, y) inside the [i, i + 1) x [k, k + 1) set, which is the mathematical notation for the square of the pixel. The rendering engine traces the related direction and returns with the color. The Gauss Pixel Filter samples a Gaussian distributed pseudo random 2D vector (dx, dy). The pixel containing the (x + dx, y + dy) vector gets lit with the traced color.
Probably this is done in Blender.
Second Possibility
Given the i-th columns k-th pixel indexed from 0, the Sobol Sampling Pattern gives a uniform pseudo random 2D vector (x, y) inside the [i, i + 1) x [k, k + 1) set, which is the mathematical notation for the square of the pixel. The Gauss Pixel Filter samples a Gaussian distributed pseudo random 2D vector (dx, dy). The rendering engine traces the (x + dx, y + dy) related direction and returns with the color. The original pixel gets lit with the traced color.
Why these result the Same
For every x, y, dx, dy where (x, y) is contained in the i-th columns k-th pixel pixel and (dx, dy) is a possible outcome of the Pixel Filter, the events below have the same probability:
First Possibility: The Sampling Pattern sampled (x, y) in the mentioned pixel and the Pixel Filter sampled (dx, dy).
Second Possibility: The Sampling Pattern sampled (x + dx, y + dy) in some pixel and the Pixel Filter sampled ( - dx, - dy).
These events have the same probability because all Sampling Patterns have uniform distribution and all Pixel Filters have a symmetrical distribution.
This means that both possibilities converge to the same image.

Thanks! That's interesting. Let me see if I understand correctly: using [a Sobol sampling pattern with a Gaussian pixel filter] is the same as using [a sampling pattern that is the convolution of a Sobol pattern with a Gaussian, and no pixel filter at all]. Is that right?
Also, your answer tells me that the pixel filter is not applied in post-processing, but is, in fact, done when casting the rays. Right?

(And in that case, the sampling pattern and the pixel filter are in a sense the same procedure, namely sampling according to the convolution of the pattern and the filter.)

Yes, me to have just realized, that technically it is the same as using the Gaussian-Sobol convolution function as sampling pattern. During the whole sampling, you can see the noisy Gauss distributed white dots in the preview like in the images I attached.

It is desired that the Sampling Pattern is uniformly distributed on the area of the pixel. I guess being able separately choose these two functions rather than from a huge list of all possible convolutions is better. Also, the common Pixel Filter functions are used in other type of renderers, where sampling is done over the whole image rather than pixel-by-pixel, and one sample really lits multiple pixels (the Pixel Filter is not stochastically sampled but fully calculated), like LuxRender.

I am interested in the topic and I try to understand what you are saying about sampling and using Gaussian-Sobol convolution. If I get it right, number of points (x,y) are randomly sampled within the pixel using Sobol sampling, which is one of possible sampling patterns. They are traced, get some color value. I assume this value gets assigned to location (x+dx, y+dy) instead, where (dx,dy) - Gaussian noise. And this is called a pixel filter.
And if I am correct all samples within a pixel get combined using e.g. Gaussian weighting to get the final pixel value.
Now if you instead apply Gaussian noise to the location first and then trace (x+dx, y+dy) you won't get the same value. So I don't think you can combine these operations, unless you also average over samples outside the pixel when computing pixel values (and don't average over other stuff that got into your pixel from neighbouring ones). But maybe there are reasons to do it this way and not the "inverse" way. The inverse way samples that were dropped outside the pixel will get very low weights if also use Gaussian when combining them.
I am actually very new to this stuff, I think my answer is right, but sorry if I misunderstood something.

Yes and no: I also think that the Pixel Filter gets applied post sampling. But you should get the same result. I will explain this further soon.

@Róbert László Páli, I added some information to my answer about the final pixel values. However, that's was a bit guessing, Blender internals is quite a mystery for me.

I updated my answere with my reasoning why the convolution would work.

I think sampling pattern is literally just the order your tiles get sampled in and does not relate to the blur itself.


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Export video from Game Engine scene
I've tried to follow this tutorial to create a simple bouncing ball in Game Engine.
When I run the animation pressing P ("run" being different than "play" that we can find in Internal or Cycles rendering engines, and not related to a timeline), the animation plays fine.
But I can't seem to find any documentation anywhere as to whether or not I can export this as a video file, like I would with the "Animation" button from the Rendering panel in the other engines.
On this old page there's a script that seems obsolete, and people on the discussion board just seem to end up going with a screen capture tool, which is a limited solution in terms of resolution. Also a script is a little too far advanced for me at the moment with my knowledge of Blender.
So, can a Game Engine scene be rendered out in PNGs like in other engines?

There is no checkbox called "Dump framebuffer to disk", so you will have to use a script for this.
The core idea from that old forum thread is good, call bge.render.makeScreenshot() every frame with different filenames.
In the Text Editor, make a script file with a name like "screenshooter.py". That script will handle a frame counter, will make a filename based on that frame counter, and will give that filename to makeScreenshot().
from bge import render

counter = 0

def shoot():
    global counter

    filename = "bge_rendered/frame_" + str(counter).zfill(8) + ".png"
    print("Saving to " + filename)
    render.makeScreenshot(filename)

    counter += 1

In the Logic Editor make:

an Always sensor, with "Activate TRUE level triggering".
a Python controller, set to Module execution method, executing "screenshooter.shoot".
the two connected together.

In the render settings, disable "Use Frame Rate" to disable frame-skipping, otherwise there will be a lot of duplicated frames and jumps in the animation.


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Export only some visible parts of an object as SVG
I am making a striped tunnel like this:

The result looks like this which is very satisfying:

However I want to export only the black rings, and as a SVG from Blender.
I have converted the object as a Grease Pencil, then exported as a SVG but the result makes the black and white rings the same color, which is too confusing:

So I decided to delete the faces corresponding to the white rings in Blender, and convert to Grease Pencil then export only the black rings as a SVG.
However the resulting SVG element is very difficult to work with, because it exported the whole shape as vector elements placed on top of one another:

Removing the hidden part of the tunnel is extremely tedious in Illustrator, because some shapes are half-way between visible part and hidden part and therefore need to be edited one by one.

I tried exporting the black rings as one vector file and the white rings as another one to do a Pathfinder effect in Illustrator but that also didn't work as it removed parts of the black rings as well:

How can I export only the black rings in the camera's point of view of Image 2, without the invisible parts that are hidden ?


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What causes these streaks in my procedural hair texture?
I am trying to add a procedural cow hair texture to 4 letters out of a word, and I am noticing vertical streaks that do not seem part of the hair simulation around the edges of the mesh:

I tried changing node values and Particle settings, but nothing seems to fix this. I am happy with the way the texture looks now and I would like to keep this appearance (but minus the lighter streaks).

It's the hair direction.
When you create few hair in random positions, some faces get no hair.
Then an interpolation happens to create "children" hair, and the direction of the children varies from on hair to another.
If a hair near the edge is on the side while the top has no hair near the edge, the interpolation will create hair bending towards the side on the top face (and the other way around happens too)
If you disable the "children" hair and create more original hair with the emission, this gets solved:

You can also keep the children provided you have enough emission (I'm not sure about what the children actally do that differs them from the parents)

Thanks! I followed your advice and I am still seeing some strange artifacts around the edges (the white dots) do you also have this issue? https://imgur.com/a/jrh7Aw5

That might be too many children or too few samples in cycles. I start getting strange results if I increase the amount too much.

I am following the first part of your advice so there are no children. I will try increasing the samples - thanks

I mean, you need "more samples" or "less hair". (Not an expert advice, though)


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How to extrude in a circle?
I am trying to import a .svg shape and extrude/rotate it to make a round object.
What I have now:

A SVG file
I want to make it an object like this:

Until it looks like this with the faces filled out:

I have used arrays in the past, but when I try to use an array for this nothing changes when I offset it on the Z axis.
I am also getting an error message saying "The offset is too small, we cannot generate the amount of geometry it would require". My object seemed really small when I imported it, I designed it in Illustrator an imported it and it should be about 68mm wide in total).

https://blender.stackexchange.com/questions/139864/rotate-a-2d-cross-section-to-make-a-3d-object/ https://blender.stackexchange.com/questions/78961/how-do-i-get-the-screw-modifier-to-go-around-the-y-axis-for-a-2d-trace/78966#78966


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Select all visible faces (possible script needed?)
I have a very large and complex model that I'm working on, and I need to separate the external faces from the rest of the mesh for various reasons.
I decided to try making use of the Limit Selection to Visible feature to select all of the external faces, and then use the P command to separate the mesh.
Unfortunately, I'm having some trouble actually selecting all of the external faces this way. I had planned on dragging the Border Select over the entire object, then rotating through the appropriate angles and repeating until all of the faces were selected however, the selection tools aren't selecting all of the visible faces.
This is what happens when I'm zoomed out and I use the Border Select on a region of the model. Upon close inspection (zooming back in) I can see that there are a lot of faces that weren't selected. [See image directly below]

If I use the Border Select on the same region while zoomed in, it selects a lot more of the faces; though still not all of them. [See image directly below]

It seems like the selection accuracy decreases, the further your view is from the model.
I need a way to select ALL of the visible faces. Is there a way to fix the  selection accuracy, or a feature that I'm missing? Does anyone know of a script (or would be willing to make one) that is able to do this?

Try to select one of the front faces and select similar Shift+G>Normal and then you can extend selection with Ctrl and +

If the outer shell is totally separate from the inner faces just hover one vertex of the outer part and press L to select all linked, or select one of it's vertices and press Ctrl+L to select all connected.

Denis and Duarte, thank you for your suggestions. The outer shell is in fact connected to the inner shell so unfortunately the Extend Selection (Ctrl + +) "bleeds" into the inner shell.

Mr Zak, thanks for your response. I cannot upload the full part, however I did slice a piece from the mesh that can serve as a good example of the overall part. As you'll find, the internal geometry is quite bad, which is one of  the reasons that I want to separate the external faces from the rest of the mesh. Here is the example mesh:

Well yes, that's complex thing. The simplest way as of now is to enter Weight paint and paint weight of 1 on the outer part with Limit Selection checked. Weight Paint is not as bad at selecting as Edit mode. After that you might want to clear zero (or almost zero)-weights vertices, like here. Note that it won't make everything good - https://i.sstatic.net/CC3wG.jpg. Still I couldn't call the outer topology good as well..

The simplest way to select only one part of that mesh would be to enter Weight paint and paint weight of 1 on, for example, outer part with Limit Selection To Visible checked:

After that you might want to correct some weights which came through the outer part to the inner part:

Then clear zero (or almost zero)-weights vertices, left after the second step with Clean tool from the Toolshelf as outlined here - How to batch remove zero-weight vertices from vgroup?. Note that selecitng in this way won't make everything, because the resulting selection isn't really clean:

It might be a good start; you can eliminate some of the selected vertices by toggling Face selection mode.
As was said it is not a perfect solution, but I think it is the best way to accomplish this as of now. I appreciate the suggestions that everyone provided, and I believe I can put this question to rest for now. If anyone else comes up with an alternate solution at some point in the future, that would be great.

Please incorporate some details in your answers here as that's how this site works so not jsut copy-pasting comment. Thanks.

Select one of the front faces and hit Shift+G and from the menu select Normal.
Hit F6 to bring Select Similar operator menu and adjust the Threshold until all the front faces are selected.
Use Ctrl++ to extend the selection


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My hair particle are pointing upwards and downwards, how do I make it point only upwards?
I am trying to add sprinkles to my doughnut, but I cannot get my hair particles to face upwards alone, Mine faces both upwards and downwards.
I would greatly appreciate it if someone who knows how to fix this can explain how it is done.

What have you tried? What exactly isn't working? A few details would help. Some things to try: Vertex groups, separating objects, and hair combing to erase particles

I want the hair particles to face upwards.

I don't think you understand what the issue is. The issue is the particles are being emitted from the bottom of the mesh. Making them face the other way will just make them be inside the mesh in the same spot

So how do I emit the particles from the top of the mesh?

Did you research and try what I suggested? We have no idea what you have tried, so we can't help you. You need to edit your question and add some more details

If I understand your question properly, this is what you are trying to achieve. If yes then follow these steps:
Select the top faces and assign them to a vertex
group like this:

Then in the particles tab go to vertex group > density option > select the vertex you made (default in the name of group)

i think it is important you mention the term 'weight paint'

Weight painting is a way of defining vertex groups, it is not related to this method of assigning vertices to a vertex group


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Ambient Occulsion Artifacts.

I'm working on a Tie Fighter and can't figure out why my wings have small black triangles (left/right) during the AO baking.  Any clues what may be going on?

Is there any hidden objects?

No.  I found my problem is that on the wings.. those faces in particular where intersecting each other slightly on those edges =(  Sorry for the post.

Add an answer, such as "intersections in meshes cause ao artefacts". That way other can gind it in searches.

Possible duplicate of What can I do to get rid of ugly triangles


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No objects or images found to bake to... again
I've read though many threads related to this and I've yet to find one that works for me.
I have a single object that I originally baked some AO to.  Days later I want to go back and rebake it.  The only problem is, no matter what I do, it won't work and gives me the error every time.
I've made sure the object is selected and the render (camera) icon is ON.  I'm using the standard Blender Render method.
I've attached my scene and left it right to the point to where you should be able to click "Bake".  Can someone please tell me what I'm doing wrong??  I really don't want any "hack" related answer and am desperate to know the exact issue.
Attached Object
Thanks,
-jeff

Baking started to work when I set Duplication to None (in Properties -> Object tab).

Thank you so much.  Is this setting the default?  I guess I need to research what that all relates to and how/why it was set that way!


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Step-by-Step selecting and moving vertices to absolute positions
I'm not sure why this is so hard in blender or perhaps not (I just don't know how to do it).  Please look at the below model:

I want to accomplish 2 things.
1) Drag select all topmost vertices (there are 4 as one is behind another one).
2) Move all of the Z locations to an exact world coordinate (0.2)
Now please tell me in the least amount of steps how this can be done in blender.  In max I can just drag/select all vertices.  I can then update all of their Z values in 1 input box to drop them all down in one operation.
I know that blender is different but I'm used to modeling building block pieces like this and require this kind of functionality all the time.
If there is not an easy way to do this then please tell me how you all model to get accurate building blocks.
Thanks,
- Jeff

Hit N button in 3d view window, that will open a panel where you will be able to update transform values.

OK.  I'll try that.  Any idea on how to easily mass select vertices sharing the same plane regardless of if it is behind another one or back facing?

B shortcut to box select in wireframe mode

or C brush select in wireframe mode, press g and z to transform the selected vertices along the z-axis

In the 3D view, press N once or twice to open the
right-hand sidebar.
Find the '3D Cursor' Section and set the Z value to your desired
value, 0.2 in this case.
At the bottom of the 3D view, set the Pivot Center to '3D Cursor'.
Drag select your vertices with B.
Hit S (for scale), then Z (to limit scaling
along the z-axis), then 0 (zero).

The B for box select is exactly what I was looking for.  However the other idea to simply use the N button to set the absolute positioning without any 3d cursor was much faster and simpler.

I agree. In this particular case, making a direct change to the vertex coordinates is faster. Consider, however, other cases, which are much more likely to occur: You need to align one or more vertices to another vertex. Sure, you can read that one vertex's coordinates and manually apply them to the other vertex, or you can set the 3D cursor to that vertex (Shift + S, select the other vertices, and scale to zero along the appropriate axis. This workflow will serve you well for a broader range of circumstances than the narrow scope of your question. Food for thought...

Blender rookie here. In Blender 2.82, is it not enough to select the vertices, and set the value in the right sidebar > Item > Transform > Z?


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Do you know about any good photo / 3D references sites?
Do you know about any good photo / 3D references sites?
I want to create a 3D human models but I need good references for it. Do you know about any free or paid site that you trust? Thanks

Possible duplicate of Resources for Blender, Rererence Images for Modeling

I would like to introduce you my 3D.sk (biggest photo reference database) site where we actually offer new 3DScans! Oh, and we also prepared several packs of free photo references, 3DScans and 50% discounts for all of our portals for 3D fans, don't miss!
Download here: https://christmas.3d.sk/
Best,
Adam

Used to be a member and I can vouch for 3d.sk being a create resource for human reference.


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How to animate an object to revolve around a fixed point in blender?
I want to animate the revolution of earth around the sun in blender. I know that keyframes can be used to make an object revolve on its own axis. But how do I make an object revolve around an external fixed axis?

As example I have a cube that revolves around an empty

Add empty and add cube

Select the cube and then select the empty and press ctrlp and select Object, the cube is parented to the empty

Select empty and press I and select rotation, so the empty has a rotation keyframe

the timeline you can use to pick another frame and enter 360 in highlight and press I to insert a keyframe:


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Assigning parameters or constraints to a model?
I want to build model with certain parameters and constraints.
For example, I built a tissue box model in blender. I then want to assign parameter name hole width and hole length such that when I tweak these parameter, the hole of tissue box will resize automatically according to the parameters.
I am not sure if blender (and general 3d software) support this figure.

If you want to create your own addon then look at the archimesh addon which was added to the standard addons in 2.78, it provides parametric building objects. A more end user oriented option would be the sverchok addon.

You could look into procedural modelling with drivers similar to tutorial

From version 2.93 onward, these types of parameters can be exposed using Geometry Nodes.  The feature is still in development, but it is fairly mature at this point.
You can connect a noodle from the Group Input node to any geometry node input to expose the value in the pane in the modifier stack.

You could add Shape Keys to change the size of things in the object. Also you could try to do it with hook modifiers. Another way to do that thing with the hole you mentioned would be to add a boolean modifier to the main mesh and set it to difference. Then add a Cube (Or whatever the Hole has to be shaped like) and translate it to the correct position. Put the name of the cube in the boolean modifier field and then you can control the hole by scaling that cutout object.
But your task sounds more like a thing to do in scad.


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How Do I Move a Face Entirely on Its Own?
I fairly new to blender and i'm trying to move a specific face on its own. When I have the face selected and use the move controls, it tugs the surrounding area with it. I was doing it before but I think I accidentally hit a shortcut, and now it no longer responds this way. How do I fix this?

Possible duplicate of Duplicate objects transformation applies to both objects

are you talking about the face is stretching the edges it is connected to, or all the surrounding geometry?

You could easily go into edit mode and select the Face you want, After you have selected it press P, it  should open a small window, then just click selection and now you have made that face its own object. GL

When you press G  check the mouse wheel up and then move mouse up and down to do what you mean, you will be known.


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Move Object auto snaps to full values
If you hold Ctrl while translating objects move by full values. I must have pressed some buttons accidentally because for some reason right now its the other way around. I have to hold Ctrl while translating everytime to be able to translate an object normally without it snapping to full values. I don't know how to revert this, reopening doesn't work.

Indeed. Thanks man I was about to snap myself lol


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How to paint texture onto UVMap in Texture Paint Mod
I want to paint moss and rust (etc) onto various objects in my scene. See below. The mesh is too spread out on the UV Map therefore Photoshopping directly is not possible. Since you are able to paint color onto the object I was wondering if there is a way to directly apply a texture onto an existing UV-Map in the same manner as seen in the screenshot below.
The only other alternative I see would be to Export the UV result (left picture below) into photoshop and use the orange color as an Alpha filter for an additional texture such as Moss. It would be painfully complicated and slow and there would be visible seams around edges that are Split by the UV unwrap.

https://blender.stackexchange.com/questions/76389/normal-map-when-painting-in-blender/76395#76395 Check my answer here, you have even blend file with example there.


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Split Faces in UV Mapping
For some reason faces in UV Editing are glued to each other. How do I split them from eachother?

Also related - https://blender.stackexchange.com/questions/56270/uvunwrap-splitting-other-edges-besides-seams?rq=1

https://blender.stackexchange.com/a/3318/34004 answered my question. The top answer is no good.

Mark the seams yourself in Edit Mode.
Press ctrl+e and mark seams (seams are like the cutting edges for UVs). Then unwrap the UV again.

Doesn't work lol

Did you Mark the seams in object mode in the object itself ? You also have to make new uvs then

I thought I should mark it in UV mode. Edited accordingly. This method is much quicker though https://blender.stackexchange.com/questions/3317/separate-selected-uv-map-vertices-from-surrounding-vertices/3318#3318 Although I agree with you that one should plan in advance and mark the seams accordingly.


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Move vertices along an angle?
If I tap G twice I can move vertices along it's adjacent edges. Is there any way I can move it along a straight defined by the edges without changing the angle to the opposite edge? Just like that:

Try to press "control" button while you are moving the vertices.

Possible duplicate of Vertex slide past edge limit?

+Mr Zak Indeed it is, the answer however doesn't work for me. GG, move cursor on desired axis, C did the trick, thanks to DuaneDibbley. I cannot access clamp settings with alt. I believe the answer is flawed but I will leave it to others to correct...

edge mode,oriental change to normal,then g the egde


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Have Lamp/Light automatically rotate towards an object or the 3D cursor
How can I rotate a Hermi light source so that it shines towards a specific object or the location of the 3D cursor?
Bonus if the light source adjusts its orientation if I manually move the tracked object.
It don't have to work for animations, I've got only a static scene.
I already tried the Object Constraints "Track To" which was mentioned in a similar question but I have to choose between X, Y, Z axis but I want all three?! Am I just using it wrong?

You can't track to the 3D cursor but can easily track the lamp to an object via the Track To constraint.
Select the Hemi lamp and add the Track To constraint as follows :

Here I've set the Target to an Empty. Note that the To is set to '-Z' and Up is set to X (but could just as easily been Y - it must not be set to the same axis as To otherwise the constraint is invalid and will not work).
Moving the Empty will now automatically orient the lamp to point to the Empty. This will work equally well for Sun, Spot, and Area lamps but is obviously not generally relevant for Point lamps (since they don't have direction).
It is unfortunately not possible to automatically point the lamp to the 3D cursor (except, perhaps using a python handler) but this shouldn't be necessary as it's a simple case to move the Empty to the 3D cursor via the Snap-To menu (Shift-S, Selection to Cursor).

Thanks, I needed to read the Blender Wiki page twice after seeing that it indeed works to understand that a lamp is a 3D object like any other and thus cannot face towards the target with all its sides at the same time. So I have to choose the one of its 6 sides ("local axis").


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I need to do a very simple terrain with texture map
I know nothing about Blender and I need to do a very simple 3D terrain with texture map.
I have a 1000 x 700 height map:

And I have a 1000 x 700 texture map:

And I want to combine them into a 3D model that I can view. I have done this before, about 8 years ago, in XNA but none of my old code will compile anymore under Visual Studio 2010.
I apologize that this is a very simple question. I'm not a CGI artist and I don't anything about Blender but I know that it can do this simple thing.
What are the steps to do this with Blender?
Thanks for posting the steps but I don't have Import -> images as planes. I just have this:

Am I in the wrong place?
Thanks in advance!


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Add driver menu in osx
I wanted to create an ik switch in blender, but I'm using a mac. At some point I have to right click on my influence bar under the bone constraints tab to add a driver, but the typical mac simulation of a right click (ctrl+left click) doesn't work.
Does anyone know how I can bring up the influence menu.
Thanks.

In order to bring up the influence menu to add drivers in OS X, press the command key + click. Make sure that your user preference is set to right click and tick on "emulate 3 button mouse".


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bones causing weird scaling of the mesh
when i rotate a bone, it causes strange scaling outside of its weight painted area. As you see in the top imange, what the object should look like, but in the bottom imahe, it is deformed to make the arm half length.
before

after

Hard to see, you may turn X ray on, on the armature. But we can notice that the selected mesh is not scaled to 1. Try to apply scale on it (ctrl+A then scale).

PERFECT, applying the scale fixed it, thank you so much!


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Problem with camera orientation in motion tracking
sorry for my English, I write from Italy. I'll try to explain my problem.
I'm tracking a footage with a solver error 0.2973. When I try to set the floor, the orientation of the camera is wrong (see screenshot).

So I tried to manually orient the camera, but even if well oriented respect to the xyz axes, geometry is incorrect as you can see from the screenshots below (the selected marker appears to be on the same plane but it is lower).

The video was recorded by a roof of a house so much higher than the road. It seems that Blender is not able to recognize this height and set the floor in a wrong point of view.
Can someone help me solve this problem?
Thank you

Can you include a google drive or similar link to your .blend file/video?

Hi and thanks for answers.
I oriented the camera just like that. The problem is that by rotating the camera (and all the markers), all track point that before the rotation were on the floor, after the rotation are located under the floor.
Here is the link to download the project and the footage:
https://1drv.ms/u/s!AkNHGG_7aD9OlxzO_OZ0KU3scYf2


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How would I set a precise width of a road comprised of multiple edges?
I have a road shrink-wrapped to a terrain created by using the OpenSteetMap add-on.
In object mode, the dimensions cover the entire range of the terrain that the road covers. The dimensions report the width and breadth of the road network on the terrain.
I would like to set the width of the road segments in the overall road network.
Scale and Extrude don't seem to be the answer.  I have been going through a few books and on-line courses and have not found a solution.
Is there a modifier or other transform that can be used to set the width of the one or more individual road segments in Edit mode?

My suggestion is to use a curve which will keep the segments of consistent size.
1.) Create the curve:

Create a plane for the road surface (although you could use a cube) and loop cut it multiple times (the more the merrier) and scale it out:

Add the Curve modifier to the plane and select the curve.  You can also scale it to the desired length:

Finally, use the MeasureIt addon (included with Blender) and proportional editing to get the segment the exact width you want.

@DougKimzey - You're very welcome.  Semper Fi

@DougKimzey Don't just thank in the comments, upvote instead. And if the answer solved your problem consider marking it as accepted.

You can use a Smooth modifier with a vertex group to control how much the modifier affects the mesh:

Then, you paint the vertex group to adjust the width:


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Is it possible to lock the scale when entering dimensions?
I have a Grid Floor with an area of one square kilometer and an origin at (0,0,0).
I would like to add a wireframe cube centered at (0,0,0) with a with dimensions 250 m by 250 m by 250 m.
On the Transform panel, when I lock the Location at (0,0,0) and lock the Scale at (1,1,1) and set the dimensions, the scale; although locked changes to (250,250,250).
Is there any way to lock the scale at (1,1,1)?

You cannot do that, changing dimensions works specifically by changing the scale, if you blocked it changing the dimensions would not work at all.


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Parent-Child object relationship disappears after exporting Wavefront(obj) format
I have 2 objects in Blender named A and B.
I set A as a parent of B by ctrl+p command after choosing both objects.
After I exported it as a wavefront (.obj) format , when I try to import it in a new Blender, the parent-child relationship disappears and 2 objects seems independent of each other. Is there an export option that I missed in order to preserve child-parent relationship ?

From the Wikipedia page for Wavefront obj :

"Obj files also do not support mesh hierarchies"

If you want to keep the hierarchy, you'll have to use another format such as fbx.


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"Invalid clnors in this fan" warning
I have this jointed arm model in this blender file.

First of all I am joining "left_arm" and "left_arm_ring_in_part" with ctrl+j after selecting both of them.
After that, I am selecting my new joined object "left_arm" ,switching edit mode and click on "remove doubles" button it gives "Invalid clnors in this fan!" warning twice after removing doubles. It doesn't seem problematic now but sometimes it gives that error almost 200 times repeatedly (e.g. while using "3D add-on" on this left arm for make manifold operation).
Does anybody know how to solve that ? Thnks in advance.

The problem is due to custom normals. "clnors" means "Custom Loops Normals".
The meshes have custom normals which means that their normals have been set (instead of auto calculated). When you join several meshes and/or remove doubles this custom setup cannot be maintained.
On each mesh you should do the following (before of after joining them):

Use the "clear custom normals" button (in the geometry data panel)
Remove doubles
Set smooth
Uncheck 'auto smooth'


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How to model wavy pattern on the surface?
G'day to all B3D community!
I started working on the project to model fitness bracelet and have no any idea how to model wavy pattern on the surface! Maybe you, guys, know some ways of doing that?
I've attached an image of what I'm talking about!
Thanx a lot in advance!!!

Sketch curve, convert to mesh and then refine.
Sketch pattern main feature:
I would start from the sketching the main lines of the pattern using a bezier curve. First thing to place are the start and end point. Grab them around upon a reference image. Then adjust the handles orientation to match the reference curve's tangency (vertical) like the image below is showing:
.
Create main geometry
Now that we have the curve, set a bevel object (the black arrow in the picture is pointing mine) to place some faces to work with. At this point you can temporarily add modifiers to the object to get an idea of the final apparence of the pattern:

Convert to mesh and edit the object
As for the final model I plan to use the subdivision surface modifier, I kept the curve's resolution low before converting the curve to mesh. After this, run the symmetrize command to mirror and duplicate the mesh around the origin. Then clean up a bit the model by deleting unecessary faces:

You'll have to repeat the operation to take care of the border in order to achieve a fully tileable mesh. Fill the voids with the faces paying attention to not work outside the imaginary boundaries of the figure. You should come up with something similar to the image below:

Final retouches and modifiers
Now that the basic shape is ready you can tweak each vertex position manually, with proportional edit enabled, or even with the sculpting tools, or using the smooth vertex command... in order to achieve the right shape. You can also alter the topology with the knife tool, edge collapsing, deleting and creating faces... till you reach a satifying result.

G'day Carlo! Thanx a lot for your help! Your and Tooniis's answers gave me good lessons of how to think outside the box! I have some small stuff left to fix, but I think I can do it myself...

G'day Carlo! Looks like I really need extra-help for this one.... It is just a test modelling.... I did as you advised, then I applied Array and Curve modifiers.... By the end - shape of this bracelet came with some artifacts and not smooth... So, my question is - how to make that shape smooth along its shape? I have an image of what I mean, but I don't know how to attach it to my comment here.

You can upload the image somwhere and post the link, or even start a new question, as the problem now involves arrays, smoothing, and artifacts, not patterns. BTW, for the moment I can only guess that maybe you are not merging arrays elements correctly.

Ahh! Ok.... not merging arrays elements correctly...Ok, as you said - it is easier to start new question and upload my image! Thanx for you help - gave me something to think about!

Create a similar texture (in GIMP or other image processing software) then add an image texture node to the material and connect it to the displacement in the last node.
This will help you if you are using cycles. I don't know how to do it in the internal engine.

Thanx, mate! I was thinking about that....but decided use only Blender modelling techniques to deal with that stuff, but stuck.... I'll try what you suggested! :)