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Boolean difference not working
I tried looking up ways to resolve my issue, but it seems like nothing has worked.
I have a cylinder that I'm trying to punch a specific shape into. Originally, I created the shape combining a bunch of different objects and it worked fine. Then, I discovered I needed to change the shape slightly, and since then it has refused to work at all, even when I completely re-made it from scratch.
I read questions answered elsewhere and tried removing double vertices and recalculating normals, and even tried the 'flip normals' option, but nothing is working. Instead I've gotten a slew of different errors as I've tried, everything from the "cannot execute boolean operation" to the model I'm cutting into disappearing completely, to it cutting into the cylinder... but in completely the wrong shape.
I'm pretty new to blender, so this has been pretty confusing (especially when it worked fine the first way I made it!) Any help would be greatly appreciated.
I'm attempting to make a hole in BOTTOM with HOLE PUNCHER NOPE.

And here are the pieces before they're combined.

It is unclear in the file you have provided which cylinder you are trying to use a boolean on and which object should be used to boolean. Please add that specific information to your question.

Added! I also added a second file of the hole puncher before I combined it.

Just from a quick look at it your "HOLE PUNCHER NOPE" seems to have a pretty sloppy and messed up geometry. Disconnected edges, wholes, missing faces. It doesn't seem to be a closed watertight manifold mesh, that alone is enough to make Booleans fail.

Your HOLE PUNCHER NOPE object seems to be a pretty much a revolution object, it could be easily and cleanly modeled by drawing a simple profile and using a screw modifier.
That will yield a cleaner consistent geometry that will be error free and less prone to errors using boolean modifiers
Recreate your object from scratch by draw a single continuous bi dimensional edge profile by extruding from a single vertex and tracing over your existing object with snapping to make it easier. Then you can add a Screw modifier to it.

Recalculate the normals on your "BOTTOM" object, add the Boolean modifier and it should work.

I drew it by making a new plane and adding vertices, then used the profile I created and looked at it with a bottom view, using the Spin to create the object. Worked out pretty well and my newly created one worked just fine :)


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MakeHuman character not appearing when rendered
I'm am fairly new to using Blender (version 2.77). This is also the first time I've imported a character using MakeHuman. I've looked through a ton of youtube video tutorials as well as previously posted questions and nothing has worked yet. My problem is that when I try to render, the character is not visible.
I've uploaded my file here:

Thanks for your help!

In the node editor, change the transparency in the last mix shader !

Properties Editor->Material->Transparency
You have to do that to every texture you can select them one by one in the Outliner Editor
Plus it looks like the Specular Hardness is set too high
Properties Editor->Material->Spectacular->Hardness
Basically the textures need alot of work.
Was probably imported from a different program.

it looks as it was imported the wrong way. try to re-export from MH and then re-import to blender. it's better to use mhx2 format instead of old mhx one. it handles materials and rigs better. if your MH doesn't support it, then you need to download latest version (1.1 does support mhx2). then you'll need the mhx2 importer for blender. just google mhx2.

Transparency has been enabled in the shader. Do UnCheck it.
Cheers.!

Please give steps or screenshots as to how the user should 'UnCheck it'.

source: Stack Exchange

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

sort: votes


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How to make different layers of mesh in circle z-axis by grouping different meshes?
I am trying to group many meshes in a colour and aligning them together. My aim is to make a ring of colours so they have a layer or ring that will go in. I think it is a little bit difficult to explain. Please see the Picture 1 below.

I think you can see what I am trying to do. The inner core should be green meshes and it should be circulated by blue meshes that I have grouped and aligned together.
The end product should be like an arrow with different layers with each layer having separate mesh bricks as units.
I think you can agree that it does not look very professional and round. Is there a better way to do this rather than just copying the mesh group (see selected blue mesh second layer) and duplicating it and moving it above. How do I join two meshes on either side without doing it manually and really labouriously.
I'm new to Blender. Thanks in advance for your help.

instead of downvoting a new user question you should help him improve it

I'm typing that as we speak ;-)

Welcome to Blender Stack Exchange! You might find the tour helpful in understanding what our mission is, and what kinds of answers you can find here. In short, this is a place for people to find answers to common, generic questions. Your question is a little too specific to YOUR case, and wouldn't really be helpful to a broader audience. If you can rework your question to be more broad, that'd be great! Even as it is, though, your question would be great for the Blender Artists forum, or another forum where posts are a bit more fluid.

Particle System

A Cylinder has a Particle System.  This ensures the circular pattern. Use multiple objects with particles systems, such as a plane.  The object which owns the particle system does not need to be rendered.  The yellow [brick] is duplicated along the vertices of the cylinder.  Settings are shown in the Particle Systems Panel in the image above.  You can see many tutorial videos on particle systems on various web sites.
Click on image to see larger version.

you can add other options : array+curve modifiers  and child duplication to verts

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


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Macbook trackpad very slow scrolling/panning (disable acceleration?)
I'm having issues scrolling in any toolbar or view in Blender on my Macbook Pro 15" (Late 2016).
If I use two fingers, and move them rather slow over the trackpad, almost nothing happens. I need to scroll at a rather high speed, and thus losing precision.
MacOS doesn't work at all like this normally, so it seems to be something with Blender.
Is it possible to completely disable acceleration, so it's 100% linear? That would help a lot!
I made a short GIF to show what it looks like, but it's hard to see how I move my fingers on the track pad, but in the beginning I move them slowly, across the entire pad:
http://i.giphy.com/l3q2GD57N6muCHh3W.gif

I have the same issue, I'd suggest using a mouse with a scroll wheel, makes life much more easier.

Thanks, not a solution for me though. I can have a mouse on my desk but sometimes I just grab my laptop and sit in the couch without mouse or anything, and would like the track pad to work.. :)

The trackpad should work just fine, see my new answer. You don't need a mouse at all, I used my trackpad for quite a while before I bought a mouse.

Probably you just zoomed in really far. It's not immediately obvious, but Blender zooms and rotates around an invisible point at the center of the view, which you can see by rotating around. Try simply pinch-zooming back out again.
And you do not need a regular mouse at all—Blender has excellent multi-touch trackpad support. (Though this doesn't apply to some PC laptop trackpads without multi-touch, although if pinch-zoom and two-finger panning work, you're probably good to go.)


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Ambient occlusion where two meshes overlap?
I have a house (cube) that's on an uneven ground. On this example the ground is maybe a little to wavy to be realistic, but I find it looks rather good mesh-wise, with the house intersecting the ground, so it's not on a completely flat surface. See LEFT image.
However, there are no shadows on the house from the ground or vice versa, so it looks kind of fake.

Sun Strength 1.00 straight angle towards the house, which is slightly rotated.
World AO is on 1.00
No more lights

I made a mockup of what I expected (RIGHT) regarding shadows. How can I make it more realistic?
EDIT: Apparently it's something with the ground material, when I change it to simple diffuse, I get the desired result. I need to find out what can cause this though.

Post your node setup (screenshot). If you find a solution, please add an answer.

Thanks, I would, but it's a very complicated material that I got from Blender Cycles: Materials and Textures Cookbook
Third Edition, that doesn't even fit into one screen. Anyone have some ideas what could be causing this?

If a diffuse material works fine, and your material doesn't, the problem is your material. Try disassembling the material bit by bit to trouble shoot.

Please post your .blend with that material

For this model rather than using the World ambient occlusion why not instead bake an ambient occlusion map on the model itself? There are hundreds of resources available for how to go about accomplishing this however I would recommend using this website as a source.
http://www.katsbits.com/tutorials/blender/basic-ambient-occlusion.php
You can bake the ambient occlusion on both the box as well as the ground mesh giving you more control in how it looks.

Thanks, that's an interesting solution, however I'm looking for more reasons why no shadow shows up, rather than to bake it. But I'm rebuiling the material at the moment.


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Make smooth texture transition animation in BGE
I have a skydome model to use in my game and 2 sky materials for it I want to have it fade between during an animation, like a day-night cycle with a smooth transition between day and night skies.  I have the placements of all of my keyframes ready for the animation, but I need to know what property(s) of my materials I need to change to achieve this.

I don't know whether you can fade between two materials, but you could easily set up a mix shader within a single material and animate the factor with keyframes.  So the single material would contain shader setups for your day sky and your night sky, and the mix shader would switch between the two.  It is possible to mix between background shaders FYI (although since you say you have a "skydome" perhaps you are talking about mesh materials, not background materials . . . it's the same principle either way).

Thank you for your input but if I wasn't clear before I need this to work in the BGE.  Updated post.


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Transfer animation between two armatures that have the same structure and naming conventions but differing rest poses?
I have a skinned armature in a T-pose as its rest pose that is not animated and a second separate armature that has an animation I would like to transfer to the first skinned mesh. The only problem is that the armature I want to transfer the animation from is in a diffrerent rest pose than the target armature, and since the animation is done relative to the bones' local positions and not global space, the animation just copied and pasted to the first armature looks very wrong. EDIT: I also cannot change the skinned armature's rest pose as it needs to be that way for a specific program I'm importing it into.
Is there a way to convert the animation such that the bone offsets can be changed to the skinned armature? Something I thought of would be that empties would be made in global space that would align in their transforms with the bones of the animated armature, and the skinned armatures bones would be posed to match the positions of the empties for every frame of animation, but this seems very tedious and I can't think of anything else.
Thanks to whoever in advance.

You can try changing the rest pose of the target armature. this can help you https://blender.stackexchange.com/questions/49768/can-i-set-my-pose-position-like-the-new-rest-position

I should've said this in the post: I can't change the T-posed armature, it needs to be in that position for a specific program as well as I am trying to add multiple animations to this armature in the same way as above. Thanks anyway though.

This question has two answers that link to addons that should help. Also this answer has a script that configures bones to follow empties, should be easy to adapt to follow a second rig.

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


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The default settings RGB background are in Blender
I am rendering the image with Blender. The rendered images are saved as black and white images. I am wondering what the default settings RGB background are in Blender because I need to make the renderings consistent between Blender and the software that I use to present. Thanks in advance.

Welcome Thomas! What other application? Eevee or Cycles? Do you mean the World Background (default grey)? Why you can't just set it to transparent?

(0.051, 0.051, 0.051) in scene linear is the default value for the world background. Is that what you mean?

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


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No shadow after render
I'm new to blender and have only spent about two hours on it.

I drew an animation and it went out just fine in preview, however after I rendered it, all shadows are gone (shadows below the object & shadow of the object) which made my animation of the block flat
I only set the background plane orange but the whole output seems to be filled with some orange atmosphere

What am I doing wrong?

Blender 2.8 on MacOS

Hi, there is more info missing. Upload your file, post your settings or so. It is just guessing why there is no shadows. What is your light source? What render are you using?

how do I upload files?

I'm using a point light and Eevee render

Can you please post a screenshot of your material node? I suspect you may have created a shadeless material by accident.

How to upload blend files

Tks here you go: https://drive.google.com/file/d/1EE4eewpoqhscb2G423xdf0UHluyBvw5d/view?usp=sharing

I made some changes but still can't see shadows on the object

I seems that your light source is just your world. It wont give you much shadow. Try to set your world in darker and add some lamps. Or you can also change your world to an HDRI.

I do have one lamp lit, is it not enough?


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Weight brush tool not working
I was just following the blender guru tutorial on  level 2 part 1, and towards the end, he switches to the weight paint tool, my problem is that the paint draws toward the sides and the bottom only, but refuses to draw towards the top as seen in the picture
blender file:

Could you post the .blend please? You can use this to do that: https://blend-exchange.giantcowfilms.com

Ah, sorry, you need to edit the question and paste that code to it. Sorry for the trouble

yea sorry my bad still new to this

Alright, so, in edit mode you've hidden some of the mesh, which causes the weight paint not to work:

Just unhide all the mesh in edit mode ALT+H and you can weight paint again :)

thx alot man, that worked!

If that worked out, please accept the answer @nour7500


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How to draw RGBA 2D image in 3d_view with gpu module (or without)?
I just copied and pasted from https://docs.blender.org/api/current/gpu.html#d-image:
import bpy
import gpu
import bgl
from gpu_extras.batch import batch_for_shader

IMAGE_NAME = "Untitled"
image = bpy.data.images[IMAGE_NAME]

shader = gpu.shader.from_builtin('2D_IMAGE')
batch = batch_for_shader(
    shader, 'TRI_FAN',
    {
        "pos": ((100, 100), (200, 100), (200, 200), (100, 200)),
        "texCoord": ((0, 0), (1, 0), (1, 1), (0, 1)),
    },
)

if image.gl_load():
    raise Exception()

def draw():
    bgl.glActiveTexture(bgl.GL_TEXTURE0)
    bgl.glBindTexture(bgl.GL_TEXTURE_2D, image.bindcode)

    shader.bind()
    shader.uniform_int("image", 0)
    batch.draw(shader)

bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_PIXEL')

But it rendered in black and white colors.
So,

How to draw colored image?
How to draw with alpha?
It doesn't render it immediately - only when I hover over some view_3d interface widget. How can I force to draw it immediately?

The problem seems to be SOLVED.
I just can't understand why the image I've tested first time rendered noncolored.
Here is some Screenshots.

Second time I add image it was drawn RGB.

But why it doesn't render immediately? Is there some refresh function operator or etc.?

Sometimes the blender documentation links change so I have added the relevant code to the question.

This code works and displays colors if the image is itself colored. Could you show some screen captures of the "Untitled" image and the result?

The 3D view does not know about this script, so it won't draw immediately since some change occurs for it.
But you can force updates in 3D views using this at the end of your script:
for area in bpy.context.window.screen.areas:
    if area.type == 'VIEW_3D':
        area.tag_redraw()


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How to change the portion of a sphere I see along the polar axis?
Excuse me but as a beginner I have a second probably stupid question .
I try to create an Earth view from a point along the pole axis.
Now this view will obviously show a circle whose edge is some given latitude. If I am at infinity, the edge will be the equator and when my distance to the Earth decreases, the latitude forming the edge of the circle will increase.
Unfortunately the view seems to stay always the same when I try to zoom, move, rotate the camera etc and I can't get a view which would show the Earth up to the Equator or almost to the Equator.
What commands should I use to make the edge of the circle at/near equator ?

Are you in perspective or orthographic view? Are you using the view of a camera object or just the viewport? Would you mind showing at least one screenshot of what you see and some illustration what you expect to see?

I tried both - perspective and ortographic. It doesn't seem to change anything. I use the camera view . What I see is a circle (textured earth globe) whose edge is about 30° latitude. What I would like to see is the same thing but with an edge at/near equator.

I don't know how to post a screen shot here.

You can edit your question. Then look in the top menu bar of the edit window, there is an image icon you can click on and upload an image. It will be placed at the position of your cursor. And settings of the camera etc. would be helpful, too.

I added what I see. You can notice that I see only a part of the globe - approximately from the latitude 15°N to the N pole . What I would like is to see a bigger part - ideally the whole half sphere going from the equator to the N pole what basically means to move FARTHER from the Earth along the pole axis. And I have no idea what kind of command, menu, window, tab, key etc would help to do that. This is my question.

As it says on the top left corner of the viewport Orthographic : you are already seeing the whole upper half of the sphere.

@Vallon When you are in orthographic view, you see the whole upper half of the sphere as Lutzi already said. The thing is, no matter if perspective or orthographic view, it is still a sphere not a flat disc. So all faces close to the equator are more or less vertical and therefore perpendicular to the camera's view. As long as you don't want to flatten your sphere, you will always have a strongly distorted view onto the low latitudes.

@Vallon My answer probably does not make this clear enough, but as you say in your comment you want to move "farther" away from the sphere. You are in orthographic view, there is no "farther" away. Orthographic view works like as if you were infinitely far away, you can only scale in or out. To actually have an effect of viewing more due to distance and perspective, you should go into camera view and move the camera further away. But as I said, orthographic is already infinitely away. The reason you are not seeing everything depends on the angle of the sphere's faces towards the viewing angle.

Actually it seems to me that this is no Blender problem (and therefore off-topic for this site) but more of an issue of you not understanding how orthographic and perspective views on a sphere work...? Maybe I'm wrong, but as it appears I have to assume this.
The thing is: when viewing top down on a sphere, the closer the camera is to the sphere, the less far you will be able to "look around" it, so the less close you can view down to the equator.
Let's say, I take a sphere with a radius of 1 m sitting at the world center at (0, 0, 0). If I take a camera with a wide angle lens e.g. a focal length of 18 mm and place it above the sphere at a Z height of 2 m (and therefore 2 m above the equator of the sphere), you can see it fully in the camera's view.
Take a second camera with a focal length of 300 mm, of course this zooms in a lot more and now I have to place it around 30 m above the sphere's equator to get a similar sized sphere in the camera's view.
Here is a schematic side view of the setup (the vertical angles of view are measured for a full frame camera):

A close up on the sphere shows how much the distance of the camera to the sphere changes the visible range of the sphere. The closer the camera to the sphere and therefore the equator in this case, the shorter away is the horizon line from the camera and also the visible latitudes:

Looking through both of the cameras, this results in the following different appearances of the sphere and its latitudinal rings:

I started writing this answer before you added the screenshot to your question. There you are in Orthographic view. The difference is basically and simply spoken that the Perspective view always has a certain angle of view where all the rays converge in a focal point, while the rays in Orthographic view are parallel and not converging:

And because the Orthographic view is looking straight down without convergence, you can see the whole top half of the sphere - but that does not change the fact that the faces of the sphere down the curve are increasingly facing away from the view direction and thus are getting "thinner" and more distorted until on the equator they are perpendicular to the view and have an apparent width of 0, as shown below with an exaggerated low resolution sphere:

So with faces getting constantly smaller the further out from the pole (but using the full face width for texturing), how do you expect this to work? How should you be able to view any texture on an ultimately thin face? The only way this would be possible is to either map everything onto a flat circle instead of a sphere, or to rotate the sphere towards the viewpoint - but of course, rotating one side of the sphere towards the viewpoint will only shift the problem, because then other parts of the sphere will move out of view.
By the way, your sphere does not look like it has a very high resolution - and another thing my low resolution example above shows, the less resolution, the less faces for the curvature and since the faces are planar, the earlier the face normal will be pointing in a direction where it is not or only barely visible from the top.
Besides that, in your screenshot I can see water below India and below the Horn of Africa, I also see the upper part of South America. So to me this seems to be the complete top half of the sphere down to the equator.
Last but not least, I'm not sure how you determined that you can see only down to a latitude of approx. 15° (or 30° as you stated in an earlier comment). If you are using the mesh's edge rings centered around the pole: they are not in steps of 10°, it looks as if you used the default UV Sphere with 32 segments by 16 rings. This means between each of the rings is an angle of 11.25°, so looking from the pole at 90° the rings you see within the sphere's boundaries are 78.75°, 67.5°, 56.25°, 45°, 33.75°, 22.5° and 11.25°, leaving 0° to be the outer border - which would be the equator.

Thanks Gordon but most of what you say, I already said in the first question : "Now this view will obviously show a circle whose edge is some given latitude. If I am at infinity, the edge will be the equator and when my distance to the Earth decreases, the latitude forming the edge of the circle will increase. " I didn't want to be technical but the formula is : sin(L) = 1/(1+x) where L is the minimum visible latitude (visible edge of the sphere) and x=H/R with R radius of the sphere and H the altitude above the pole. So in technical terms my question was : "HOW can I change x in blender ?"

@Vallon I'm not sure if you read my last comment under your question. As far as I understood your question, you are not satisfied with how far down to the equator you can see and your question here "how can I change x" is mostly how you can increase x (which would mean increase the height unless you wanted to change the radius) and as I mention in the paragraphs about orthographic view and in my comment, you are at infinity - you cannot go higher and the outer edge is already the equator. Seeing below the equator is not possible.

@Vallon If I misunderstood you and you don't want to go higher but instead get closer to the sphere to see less i.e. that the outer edge is a higher latitude, then you cannot use orthographic view but have to switch to perspective view. In the viewport this means pressing Numpad 5 or using a perspective camera and changing its height above the sphere. By the way, the resulting latitude according to the formula is of course limited by the resolution of your mesh, that's why for example my camera at 2 m above the sphere could only see down to a latitude of 30° and 2.5° at a height of 30 m.


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How to Render an image of a mesh with texture with Blender4.0, so texture is shadeless
I just want to render an image of my model , which have a texture, It comes from photogrammetry and I need to export an ortophoto, which shouldn't have any shadows.
In previous versions, I only had to click Shadeless in material tab. (Now still can do it when importing an image.)

I'm not sure what you mean. I have different older versions of Blender here. Could you please tell us where you can click "Shadeless" in the material tab? Maybe show a screenshot? In which version you could do this?

https://blender.stackexchange.com/q/8108/88681

"In previous versions" - this was a setting in the Blender internal render engine, this does not exist anymore since the introduction of Eevee in version 2.80

so he is right "previous versions"

The duplicate question is a poor answer to the question in my opinion. I feel they are looking for Material Overrides with an emissive material.

@Chris In a way... :D But mentioning having this problem with 4.0 and not having it in previous versions sounded a lot like, "I'm always using the latest version but since the latest release, something is missing". It took me a while to remember this option existed in Blender internal render engine...

@AlpineWorldCup I don't think so. It is mentioned nowhere that there are several materials to be overridden with a single material (it is a photogrammetry model with a textured material that should be shadeless), and the linked duplicate explains how to make it shadeless with an emissive material.

@PilukaPV could you clarify if the linked duplicate solves your issue? If not could you describe which part is missing or what part doesn't satisfy your needs?

No, It didn't. But never mind, keep the question closed. My workmate found the solution to the issue.


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Switch main viewlayers during render
I have a scene with a lot of different cameras and camera angles and I used the viewlayers to quickly show or hide objects depending of what these cameras should render. It was much quicker than keyframing the "show in the viewport/render" option for each of the items that should be hidden or not (especially when said items were to be shown again later in the video).
Now I have my scene with cameras tied to markers in my timeline, and each camera's corresponding viewlayer set up, how should I set up my render to render every layer according to it's camera use without having to render each viewlayer manually (as in; selecting a viewlayer and the frames' array, waiting for it to render and do the same for the next sequence, making it impossible to start the render and go to sleep for example) ?
The only changes between viewlayers are what elements are currently masked or not, I am not using them for composition-related stuff. I'm pretty sure viewlayers were not really designed to do this but I honestly don't know any better. Thanks
Edit: I made as many scenes as I had viewlayers with my elements in each of them set up similarly (you can read the comments to see how I'm using those with the sequencer (also do not do as i did with my first empty "master" scene nested in a second empy scene as it doubles the render time for some reason) and I noticed (after way too long scratching my head) that the "Disable in Render" was a global feature meaning I couldn't disable one Element in one scene and have it visible in the next scene. Why does that ferature works like that while the "Disable in viewport" works on a local basis is lost on me. Please help if you know how to work around this!
Edit II; As I'm quite in a hurry, I settled on keyframing the "Show on render" property for each of the objects. Hopefully someone will find a proper solution to this without having to use collections.

maybe this https://fishsnackart.gumroad.com/l/nsgkn helps you?

I stumbled upon it before posting and it seems aimed at people doing a lot of compositions and lots of different passes in blender. Maybe not but either way it's a bit too complex for me sadly. I'll try to use scenes which looks like they were designed for that instead. thanks !

I've found this on Right Click Select, people there say we can use background scenes

It would be a lot of work to refactor the file to work with the backgound scene (i guess, clean up a scene from all the moving objects, use it as a bg scene and the create full copy of other scenes containing only the objects specific to that scene), I'll investigate. Thanks again, let's take it to the chat when you'll be able to.

This has already been asked and answered here and here, you need to use scenes instead of viewlayers. with viewlayers you can hide and unhide objects, but to change cameras and render settings you need to use a separate scene.
After setting up the scenes you create a new, empty scene and add the scenes you want to render to the sequencer (Add > Scene)

Thanks, I have created linked scenes for each of my sequences, replacing the corresponding layers. I now have troubles to render them through the sequencer on my blank scene, as if it wasn't switching between scenes but would instead stay on the same scene without accounting for the editing. All my scenes are cut and assembled following each each other on the same channel in the sequencer. The editor's preview seems to work as intended most of the time. I must be missing something.

I'm going to render a second blank scene with the first one inserted in it and its input set at 'sequencer' tonight and see if I can investigate further tomorrow.

I thought I was losing my mind when I finally understood that while the "" button to hide or show an element in the viewport would be scene-specific, the "" button to do the same is not, and disabling it in one scene disables it in every scene, totally blewing the very reason i was doing all that... I can't understand why is something apparently so simple is so hard to do on my side. Is it because my scenes are linked? Please help!

The description of the "" button says that it disables the object in renders, if you change this on an object it will do the same on the linked copy.
You can use the full copy function, but that takes up WAY more space.
I'll try to find a method that doesn't require copying every object, something like visibility override.

Yeah, that's why I went with the linked copy, but I thought it wouldn't link this property since the viewport one is locally-based. As my file is too messy for disabling collections (e.g. some objects should be shown and some other hidden in the same collection) I fear the only solution left would be to keyframe each "disputed" object's "show in>render" property. That's what I used to do but it's really not an ideal way to deal with that, hence why I used viewlayers then scenes. Thanks for your help.

I will continue to look for a better way to do this, and we should also move this conversation to the chat as soon as I have enough reputation. @Gam


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Why does my mesh have gaps in object mode that does not exist in edit mode?
Im new to blender and making a character, but at some point when i was fixing some of the vertexes i started getting gaps in my mesh even tho its all connected, what have i done wrong?

How and why did need to "fix some of the vertices"? I think we'll need to see your Blend file to see what you have done. You can share it via https://blend-exchange.com/ following the instructions there to copy the link on that page. Then edit your question here and paste the link into it.

The vertices are in the same location, but they are not merged.  Merge by distance.  You have some other modifier (maybe that armature?), or perhaps a shapekey, that is moving them apart.

@JohnEason I did just as you asked and uploaded it.

@Nathan i did as a turtorial said and merged a last point. Yes i realised the problem with the mesh when i had added my armature and tried to do animations, thats when the problem occured (Or when i noticed it).

You still have 8 duplicate vertices on your model. With your model selected, go into Edit mode hit A (All) to select the whole model then hit M > Merge by Distance. If you watch the bottom status bar while you're merging you will briefly see a message saying "Removed 8 vertices".

Nice thanks alot, is that the normal way to check if you messed up with vertices? So i knew when i mess up in the future.

Unless you Grab and move a vert and find another one underneath it's often impossible to tell if there are duplicates until you start animating, I usually check by trying to merge and seeing what's been reported as a matter of course. A favorite mistake is to select E (extrude) and then use right-click to cancel without moving the extrusion if you change your mind. This will not cancel the extrusion but will leave it in place and you won't be able to see the duplicates.


text:
Batch rendering multiple scenes using 'Material Preview - Viewport Render Animation'
So I have a scene in which I'm using blender to projection map content. Im then rendering that content back out from Blender correctly mapped per each of the 8 'surfaces', I therefore have 8 cameras in the scene, each requiring their own respective resolution. This led me to create 8 scenes (which could contain resoluton information and specific cameras).
Next I wanted to automate the rendering of scenes in sequence. I tried the sequencer but that doesnt respect resolution of each scene, and then I solved this issue with a little help from the forums and chatGPT, and successfully managed to render every scene to the correct directory.
See code below;
import bpy
import os

# Define the output directory for the renders
output_base_dir = "/Volumes/New Volume/PERSONAL/The Cube/Camera Export Test"

# Ensure the output directory exists
if not os.path.exists(output_base_dir):
    os.makedirs(output_base_dir)

def render_scene(scene):
    # Set the active scene
    bpy.context.window.scene = scene

    # Construct the output path for the scene's animation, ensuring a subfolder for each scene
    output_path = os.path.join(output_base_dir, scene.name)
    if not os.path.exists(output_path):
        os.makedirs(output_path)

    # Update the scene's output path for the render
    scene.render.filepath = os.path.join(output_path, scene.name + "_")

    # Perform the viewport render
    try:
        # Attempt to use the current view context for rendering directly
        bpy.ops.render.opengl('INVOKE_DEFAULT', animation=True, view_context=True)
    except Exception as e:
        print(f"Failed to render scene {scene.name} due to: {str(e)}")

# Iterate over all scenes and render them
for scene in bpy.data.scenes:
    render_scene(scene)

print("Viewport rendering attempt complete.")

However, this rendered using the normal EEVEE render mode instead of my preference of 'Viewport Render Animation' in 'Material Preview' mode. 'Viewport render animation' + 'Material Preview' has an indiscernible difference in quality for my purposes, and no matter how much I tweak the settings within EEVEE I cannot get the render times to the same as 'viewport render animation'.
I have 10's of thousands of frames to render so both this automation and the faster render times are required. For reference: Standard render mode = 3FPS, 'Viewport Render animation' + 'Material Preview' = 14fps). I tried asking chatGPT to fix the python and force 'Viewport Render Animation' + 'Material Preview' to which it responded with this code;
import bpy
import os

def set_material_preview_mode(screen):
    for area in screen.areas:
        if area.type == 'VIEW_3D':
            for space in area.spaces:
                if space.type == 'VIEW_3D':
                    # Set the viewport shading to 'MATERIAL'
                    space.shading.type = 'MATERIAL'
                    return True
    return False

def render_viewport_animation(scene_name, output_path):
    # Store the current scene to switch back later
    current_scene = bpy.context.window.scene.name

    # Switch to the target scene
    bpy.context.window.scene = bpy.data.scenes[scene_name]

    # Update the scene's render output path
    bpy.data.scenes[scene_name].render.filepath = output_path

    rendered = False
    # Attempt to set Material Preview mode and render for each screen
    for screen in bpy.data.screens:
        if set_material_preview_mode(screen):
            # Find the 3D view and set the context for rendering
            for area in screen.areas:
                if area.type == 'VIEW_3D':
                    for region in area.regions:
                        if region.type == 'WINDOW':
                            override = {'window': bpy.context.window, 'screen': screen, 'area': area, 'region': region, 'scene': bpy.context.scene}
                            bpy.ops.render.opengl(override, animation=True)
                            rendered = True
                            break
                if rendered:
                    break
            if rendered:
                break

    # Switch back to the original scene
    bpy.context.window.scene = bpy.data.scenes[current_scene]

# Define the output directory for the renders
output_base_dir = "/Volumes/New Volume/PERSONAL/The Cube/Camera Export Test"

# Ensure the output directory exists
if not os.path.exists(output_base_dir):
    os.makedirs(output_base_dir)

# Iterate over all scenes and render them using viewport rendering
for scene in bpy.data.scenes:
    scene_name = scene.name
    output_scene_path = os.path.join(output_base_dir, scene_name)
    if not os.path.exists(output_scene_path):
        os.makedirs(output_scene_path)
    render_viewport_animation(scene_name, output_scene_path + '/')

print("Viewport rendering complete.")

Now this worked for the 'active scene', and rendered stupendously quick, but for the others it just rendered in what I think was 'workbench', or maybe 'Solid' mode in the 3D viewport. Im at a bit of an impasse here, I think this is down to the fact that 'Viewport Render Animation' in 'material preview' is intrinsically linked to the 'Active Scene' open in the viewport, and as you cannot have multiple active scenes I think theres no way to get all scenes to render correctly.
So I currently see my options as;
A) render each scene manually. Its a bit more time consuming for me , but the time saved by using 'Viewport Render Animation' is too big to give up.
B) Optimise my EEVEE render settings - do any of you know if theres a way to optimise the EEVEE normal render mode to be as quick as 'Material Preview'
I hope Ive explained myself clearly, and not asked a stupid question thats already been answered, I feel like this is a bit of an edge case as I want to use the 'Material Preview' + 'Viewport Render Animation'. Also I know ChatGPT isn't a perfect solution but its helping me learn programming in blender and serves as a good elucidator for my process ideas. Id be happy with either optimising tips or any pointers to efficient batch rendering. Thanks.
Link to scene - https://drive.google.com/file/d/1GRO68BDhmKkrE5ItCF00b3cXzHoOhvfj/view

Link to Scene;
https://drive.google.com/file/d/1GRO68BDhmKkrE5ItCF00b3cXzHoOhvfj/view?usp=sharing

Hey Duarte, Mr Moderator, I don't know how to DM you or submit a ticket, so im commenting here. To be called artificial is one this but the extraneous grammar comment hurts, I've never had grammer corrected by a mod of a forum before. if I was, it was only to make it very clear what my problem was and what steps i'd already taken.
Could you please remove the AI warning? I dont know if it reduces the ranking of my question but Im in real need of help here. Ill try to tone down my extraneous speech

I'm pretty sure Duarte didn't add the warning because of imperfect grammar. It's because chatGPT was used to generate the code. It's sad you've removed the warning, and yet you didn't care to click on the link in the warning to read the content under it, which clarifies the reason for putting the warning in your post: Concerns regarding AI generated content Also: How to upload a blend file on BSE - good practices and advice


text:
How to resize a cube to match the negative space between two planes in geonodes?
Edit: To be clear, I know how to resize a cube just by changing the the scale or dimensions of the model. I'm trying to figure out how to have the scale and rotation of a cube dynamically update to be exactly the size of the space between two planes that are being dynamically moved by a geometry node tree driven by a scenetime node. Thanks!
I'm creating a timeskip animation with a panel split background coming in, a clock illustrating the elapsed time, and the panel background splitting out to the sides again. It's all done in geonodes.
I'm trying to set up a box in the space between the collapsing panels that will hide the clockface until the panels have come in. I've got it set up with a NOR Boolean node and Delete Geometries, but I can't figure out how to tie the sides of the box to the edge of the panels. The rotation of the panels is dynamically determined by the position of the clock hands and the position is determined by number of frames used by the panel wipe.
I feel like there's a simple solution, but this is my first geonodes project, so I just don't know enough to connect the dots.
TLDR: I'd like to define the size, rotation, and position of the highlighted box to align with the edge of the panels as they sweep in.
Thanks a bunch!
(note, I changed some of the images to jpgs because the pngs were too big - the background is supposed to be transparent for all of them)
EDIT
Well, heck, I went to get a screenshot of the panel split at the end of the animation and found another bug - apparently my Delete Geometry Boolean Box setup only works when the box is square to the x-y axis. Any advice on confining the Delete Geometry effect to the inside of the box even when rotated? Maybe scrap the box defining the negative space and switch to two boxes that imitate the panel?

Resizing a cube to fit between two planes is trivial... The default Cube node's settings spawn a cube with a side of 1. So scaling the cube by a factor equal the distance between planes will yield a cube of the right size to fill that distance. For example, if the distance between planes is 15 meters, a 1 meter cube scaled 15 times yields 15 meters dimension as well...

(Using Blender 3.6.8)
Assuming the "collapsing panels" are like sliding doors, here is a proposal made with geometry nodes relying on planes to be symmetrical:

Resources:

Thanks for responding! But I found a better solution than what I was shooting for. I think. Shader issues now. Anyway - I started this whole project following a short tutorial for a simple panel split animation, and kept piling more and more features on. I finally got a solution that kind of worked but I don't think my trig was right. It was good enough though. I woke up the next morning realizing I could use static panel models and a boolean mesh modifier. For whatever reason it destroys the fps, but since I'm rendering in EVEE, it doesn't matter much. 30 secs vs 2 min. Thanks again though!


text:
Sharp Edge on Arc
When I'm making 1911 pistol slide, I have seem to ran into problem: on the top of the slide there's streak of lines which I assume to be sharp edges. Here:

Here's for another angle:
And this is what the vortex looks like, might be a little rough, but I'm fairly new into full modelling in Blender:
I tried to solve the problem myself by connecting one of the vortex in the corner to the other corner, but it's just making the streak sharper. So that's why I'm here to ask.

Hello please share the piece with the problem: https://blend-exchange.com/

I have edited my post. You can reload.

Avoid ngons (faces with more than 4 vertices) unless they are coplanar with their adjacent faces, which is not the case here, otherwise we'll see the inner triangles:

Instead use quads (or sometimes tris if it doesn't cause bad shading), if the shape is not smooth enough maybe use a cylinder with more vertices:

Thanks, moonboot! Sorry for the late reply.


text:
how to fix the creases after solidify and why it occurs?

Currently doing blender sport car creation course in blender 2.8. Followed step by step but also those pixelling after solidify doesn't go.

It's hard to tell from one picture and such a vague description. Please edit the question and explain what is wrong with it, give your question a meaningful title formed as a question, add more pictures and share the .blend file as well using https://blend-exchange.giantcowfilms.com/

Presuming you've added a solidify modifier, it can be due to inverted normals. Try shift+N in edit mode.

Thank you for replying. Sorry i am new to the website, will do fixes as you said

lemon _ thanks for the comment, yep already added the solidify but it didn't fixed. Also it goes away if i zoom in and shows if i zoom out.

@suneelgiree if not due to normals, give it a higher thickness. Or as said by Martynas upload your file so that one can have a look.

@lemon ok. i will increase thickness. I have also uploaded the blend file- https://blend-exchange.giantcowfilms.com/b/DBkn8POD

Have uploaded the file: no issues for me...

@lemon i am extremely sorry. i send it to you without saving my file been doing it since morning. wait i will upload again

@lemon i have reuploaded the file - https://blend-exchange.giantcowfilms.com/b/bzvnL1er

ok: don't use two shrinkwrap modifiers this way. Instead of the second one, try a solidify modifier, and so don't model (make faces) for the inner part of the car.

Please guide me. As per the course, first there is the guide mesh> already one shrinkwrap> then a solidify is added>solidify applied with thickness .003> then another another shrikwrap added for below face with above surface selected and -.003. As per you where should i make changes

ok, will not be an answer as it could be opinion based. But I think you should model only one side of the car, using one shrinkwrap to the guide then add a solidify modifier to give it some thickness. But visibly, I do not know the entire context of your work and the reason why you attempt to do it this way.

@lemon - even i don't know mate why i am doing this way, i just followed the course :D

So... I do not know what to advice... if your teacher wants it so... But in my experience handling two shrinkwraps like that for what's seems to be a retopo is not easy.

Ok thank you so much for your time!

This is z-fighting. It happens because of binary rounding errors when you have very thin/ overlapping geometry compared to your viewport or camera clipping range. Do not solidify your geometry before using a Shrinkwrap modifier, if you need an edge, use it after Shrinkwrap. Also you do not need all the geometry that is not visible, so you can have rim only:

You have sides of the surface in vertex groups so I just selected the inner group and deleted it to fix the issue in the screenshot. You could have the Shrinkwrap modifier before solidify there if you needed it.

Thank you so much. I am a beginner, can you recommend me tutorial or documentation related to this problem? want to go in details with it. Or maybe i should search up. Thanks

Sorry just found out you have linked the case

Sorry, I did not write too much about it, but I think it will be easy enough to find a lot of info about it since it is quite a popular topic. If you have additional questions after a bit of research, please feel free to ask.


text:
Blender 2.8 snap, knife tool does not work properly
Here is my question: https://stackoverflow.com/questions/60684130/blender-2-8-snap-knife-tool-does-not-work-properly

Vertex extrusion to edge with snap enabled has gap (snap vertex to vertex is ok)

Knife tool does not work with vertices on face

Hi. I appreciate you have already asked your question on a different stackexchange site, but please include any relevant information (like screenshots) directly in this post too. The other link could disappear at some point and make this question unclear.

Have tried Ctrl+J - but nothing happened(before selected 2 vertices).

@vsw Oh, sorry, I meant just J to connect vertices across a face :) (my fingers remember, but my brain fails)

Only J said: could not connect vertices.


text:
blender image showing transparent on cube

As I place an image texture onto a cube, the cube renders transparent, you know those black & white checkerboards.

Hello and welcome :). Please add at least one screenshot to better illustrate the issue.

please check the edited post

Hello :). This can be caused by many, many things. Please add an image of your material and maybe share your .blend.


text:
blender image showing transparent on cube

As I place an image texture onto a cube, the cube renders transparent, you know those black & white checkerboards.

can you post a screenshot of your "Compositor" tab?

shows fine on preview but not when rendered

new to blender, tried all tutorials, result same

Could you send the blend file? https://blend-exchange.giantcowfilms.com/

Hi. Please don't ask the same question twice. If you need to add information to your question you can use the edit link below the original question.


text:
PYTHONPATH ignored?
Blender 2.82a on Windows 10 - I'm trying to set th PYTHONPATH environment variable before launching Blender, but it seems that Blender's version of Python somehow has disabled the standard Python behaviour of putting paths from PYTHONPATH in sys.path at startup?  If I launch with this batch file:
set BLENDER_USER_SCRIPTS=\\ourshare\ourscripts
set PYTHONPATH=\\ourshare\ourpackages
"C:\Program Files\Blender Foundation\Blender 2.82\blender.exe"

I'd expect sys.path to contain an entry of "\\ourshare\ourpackages" and be able to import things from there, but it doesn't.  os.environ['PYTHONPATH'] does have the value "\\ourshare\ourpackages", so Blender doesn't seem to be deleting it from the environment it passes to its Python when it starts that up, which is why I'm wondering if they've customized their interpreter to not do the standard behaviour.
I can use a startup script in \\ourshare\ourscripts\startup to do the additions to sys.path, but if I want those available to all the startup scripts, the order of executing those is indeterminate (or at least not documented)?  It may be whatever the filesystem returns when Blender queries it?  It would be cleaner if we could use PYTHONPATH as we do with all our other Python-including DCC apps.

If you have the same x.y version of python installed that blender uses, can rename the blender python path and blender will pick up your system  or venv version.

Digging through the Blender C source code, it looks like they are initializing their Python interpreter with a global configuration variable Py_IgnoreEnvironmentFlag set to a value that by default is false.  This causes Python to ignore PYTHONPATH, PYTHONHOME, etc.
There is a Blender command line variable --python-use-system-env which can be set to override this.  It isn't mentioned on the current documentation page, but it shows up if you run blender --help.  I think this will solve my problems.  I'll see if I can find a place to report to documentation lapse.

It is in the advanced CLI help section somewhere.  The 2.80 doco is more up to date in some ways than others.

Looks like it was added in 2.82, but the current online docs purportedly listing all the 2.82 command line options don't reflect it (it isn't in the 2.83 dev page either).  There is a mention on a "Tips and Tricks" page.
https://wiki.blender.org/wiki/Reference/Release_Notes/2.82/Python_API
https://docs.blender.org/manual/en/latest/advanced/command_line/arguments.html
https://docs.blender.org/api/current/info_tips_and_tricks.html

I'll contact Aaron to get this included in the CLI page. The commit that introduced this change was https://developer.blender.org/rBS7c2f0074f3fe2411daa7a6e351d7cbc535246871

The changes to the manual have been committed, might take a bit until the website is updated.

The PYTHONPATH environment variable is ignored since commit rBS7c2f0074f3fe2411daa7a6e351d7cbc535246871. It caused trouble in the past, because users have set the PYTHONPATH during the installation without being aware of that Blender would attempt to use the modules of this Python interpreter. If the Python version wasn't compatible, Blender wouldn't work.
The CLI argument --python-use-system-env is now documented.

Is there some other limitation instead when it comes to the python executable? No matter what I try with BLENDER_SYSTEM_PYTHON or PYTHONHOME, you can still notice how the built-in one was started earlier.

@mirh It should work properly. Hard to say what went wrong based on your description.

Set the two aforementioned variables to whatever python altinstall you may have on your system (and even override PYTHONPATH just for peace of mind). Rather than seeing my alternative executable being run (as can be noticed by the "build date", or the "installation-dependent default" entries in sys.path), it seems like the most I can get is PYTHONHOME to be appended to the standard python binary. But no way to actually start another one (which afaik is what BLENDER_SYSTEM_PYTHON should do?).

@mirh I will have to test this and report back if I've found any issue.

My very remote guess is that BLENDER_SYSTEM_PYTHON isn't working (for some reason.. or at least the variable and parameter never seemed to make a difference for me). Assuming I'm understanding right its purpose should be "pointing to your desidered python executable".

@mirh I asked the other developers and on Windows the separate interpreter executable is only there for convenience. The actual Python interpreter is part of Blenders executable and cannot be altered by setting the environment variables. You can change e.g. site-packages through them though.

Putting aside that I don't see why that should be the case, unfortunately I'm on linux.

@mirh The same applies to Linux, the Python interpreter is part of Blender's binary and can't be replaced (unless of course you compile Blender yourself). PYTHONPATH is for setting the search path for modules files, PYTHONHOME is for the search path for Python libraries and  BLENDER_SYSTEM_PYTHON is for the Python libraries as well (just specifically for Blender). May I ask why you're trying to replace the interpreter?

The meaning of BLENDER_SYSTEM_PYTHON is documented in the manual: "Directory for system Python libraries".

Duh, spelled like that I'd argue it's quite misleading. Anyway I was trying to replace the interpreter because (of course) plugins. One I use once in a while has a library that depends on python 3.7, but many distros are already shipping and compiling blender with 3.8. But well, guess what, I just discovered that at the end of the day you can use LD_PRELOAD=/usr/lib/libpython3.7m.so and everything sticks up together magically.


text:
A moving object responds very slowly to gravity
I'm making a game and I'm using logic bricks to make my character (currently a default cube) move.
It moves (using the arrow keys) relatively fine up until I try to go down a slope or fall off an edge of some kind. When I try to fall instead of falling down as soon as goes off an edge, it keeps going in the same direction until I release the arrow key making it move.
And something even weirder is that if the object is still in the air after it starts falling when the arrow key is released, if you press the arrow key again it causes the object to completely ignore gravity again and go off in that one direction.
If you need anything to help you solve this problem I'll provide what I can.
I'm using blender's game engine if that helps.
EDIT: Turns out its falling really slowly instead of staying the same height. It's still annoying though.
Hope you can help.
Jako

Are you using character physics, rigid body physics, or dynamic physics fr your character?   (Also, are you using regular motion to move the character, or are you controlling the linear velocity?)

Gravity forces
You need to be aware that gravity is a force. This force will be applied to the current linear velocity.
The linear velocity gets increased over time as you add the force again and again, resulting in a larger linear velocity.
Therefore you get:
linear velocity = previous linear velocity + velocity from gravity

which is:
linear velocity = initial velocity + velocity from gravity + velocity from gravity + ...

Situation
I assume you explicitly set the linear velocity on key press.
In this case the final linear velocity will not add up as you already reset it as reaction on the key press.
The result is:
linear velocity = motion velocity + velocity from gravity

The gravity can't simply add up.
Possible Solutions
Motion as force
When you apply the motion as force your motion force will not override the previous linear velocity. It will be added the same way as the gravity force will be added.
This allows smooth but unlimited acceleration.
Servo Control
The motion mode "Servo Control" allows to setup a linear velocity without overriding certain axis. I suggest to enable the [Z] button and leave the limits at 0.0 as they initially are.
This allows the object to fall down without accelerating into the direction you want it to move.

You need to set your units to imperial or metric (or whatever you want for that matter).

Hi. Would be useful if you added where those options are.


text:
Efficient Landscape Mesh Optimization
I need to render an expansive landscape on a render target which lacks the ability to do heightmap-based displacement or mesh subdivision operations in hardware. Thus my only option is to bake the mesh and split it into separate static models to be loaded and unloaded when needed.
As for the landscape mesh itself, being a displaced subdivided plane, there are many relatively flatter/less dense in detail areas in the mesh that don't need nearly as many quads to be represented, but other than going through the entire mesh by hand I don't know how I can efficiently optimize the landscape.
Is there a script/workflow/outside program that can take a mesh of quads and convert it into a mesh of more efficiently-placed triangles/quads based on the shape topology? I don't know if this is the best way to word it so if more explanation is needed please ask.

A landscape mesh can be simplified, while retaining most of the shape, using a combination of tools.

The decimate modifier using the planar option
Triangulating the mesh in the edit mode

Example:
This is a mesh for a portion of Bryce Canyon formed from a quad mesh. It has about 21,000 vertices.

Applying the decimate modifier with the planar option selected and 3degrees, then applying removes about 1/2 of the vertices, leaving about 13,000 vertices.

After applying the modifier and entering edit mode, the resulting mesh has the flat regions automatically merged. A final step is to triangulate the mesh in edit mode.

Note, there are other tools in edit mode that can help simplify the mesh:

Select > Sharp Edges to select edges with high angles
Mesh > Clean Up > Limited Dissolve to eliminate edges with low angles
Mesh > Clean Up > Degenerate Dissolve to eliminate long skinny facets


text:
Copy the modeling between two objects
I would like some help ...
I have a .blend file with two objects, two bodies, body A and body B.
Body A has more subdivisions than Body B.
I wanted the body B to assume the shape of body A, have some easier way to do this?
I did not do using clipping and then join because of the amount of subdivisions that is different.
Thank you.

pictures of the two objects would be helpful.

See the image........................

have you tried the shrinkwrap modifier?

as eromod suggests, make sure the models have each scale and location applied and are overlayed on top of each other, and then use the shrinkwrap modifier on body b, and choose body a as the target.

@poseydon what do you mean you "did not do using clipping and then join"?

just realized that body a has no head, so you'd need to create a vertex group on a that does not include the head and use that in the shrinkwrap modifier.

Hi, I've been able to do with the shrinkwrap option in a group of vertices, thank you very much for the tips of all of you.
David, I was cutting parts of body A and joining body B with CTRL + J.


text:
How to delete a scene with its content?
I have two scenes and I want to delete one of them.

So I use the right-click menu to delete.

It works, but the problem is that the objects are still in the blender file. As we can see below, if I switch from All Scenes to Data-blocks in the Outliner it shows the sphere objects as well which were part of the deleted scene.
So is there a way to delete a scene with all its content (all the data-blocks)?

Save Your Blender File. And Reopen it. Datablocks will be Gone.

Here's some Python that will delete the objects and the data blocks.
import bpy

def delete_scene_objects(scene=None):
    """Delete a scene and all its objects."""
    #
    # Sort out the scene object.
    if scene is None:
        # Not specified: it's the current scene.
        scene = bpy.context.screen.scene
    else:
        if isinstance(scene, str):
            # Specified by name: get the scene object.
            scene = bpy.data.scenes[scene]
        # Otherwise, assume it's a scene object already.
    #
    # Remove objects.
    for object_ in scene.objects:
        bpy.data.objects.remove(object_, True)
    #
    # Remove scene.
    bpy.data.scenes.remove(scene, True)

# Tests.
#
# Delete the current scene.
delete_scene_objects()
#
# Delete by specifying a scene object.
scene = bpy.data.scenes["Scene.2"]
delete_scene_objects(scene)
#
# Delete by specifying a scene name.
delete_scene_objects("Scene.3")

Tip of the hat to this answer, which is where I saw the remove method https://blender.stackexchange.com/a/75348/36473

Thanks. It works for a test scene. But I found a situation where it failed. I used file links. I linked groups from files. It seems the script removes everything from the current scene but since it is a linked file it "can't" delete those objects (groups, mesh data, etc.).

Blender uses a concept of 'users' of datablocks. When you create a sphere (or whatever) Blender creates the object and any associated datablocks (eg, the Mesh data) and links the object to the datablocks - ie, the object is a user of that datablock.
When you delete something (eg, an object, a scene) Blender removes the deleted item but leaves the datablocks outstanding - this is why the Sphere datablocks are still outstanding in your file, but they are 'unused'.
At the point of saving your .blend file, Blender checks each datablock to see if it has any users. Any datablock without users are automatically discarded at that point - so saving your file and then re-opening it should purge those 'unused' datablocks.
This purging of 'unused' datablocks can sometimes be a problem - eg, you have have created a number of elements (eg, animations or materials) that are not currently in use in your project. Left to its own devices, Blender will identify these as 'unused' and would purge them the next time you save your project. To avoid this you can add a 'Fake User' by clicking the 'F' against the material, action, etc. or in the Outliner. This 'fake' user ensures that the datablock is never purged as it is always flagged as 'in use'.
In summary, save your file and re-open it and those datablocks should no longer exist.

Thanks for the answer. I read about that before, but what if I reload the blender file and the objects are still there as data-blocks? I have a more complex scene with that problem.

@Prag Most likely you have something else using those datablocks. Expand those objects in the outliner datablocks view (click the +) and check the Users and Fake User properties. If you can't find what's linked to them and they still aren't being removed then upload your blend file and someone can take a look.

That means there is no way to delete a scene with its content (all data-blocks) at once?

@Prag Try not to think of the datablocks as being exclusively part of a scene - they are separate entities that can be linked into one (or none) or many scenes. For example, a mesh datablock could define, say, a person. You might want to reuse that person many times in a scene. Rather than havig separate mesh data for each, each could link to the same mesh datablock. The same could be the case for different scenes. Deleting one scene would remove those references to the datablock but the remaining scenes could still be using it. Only when the last reference to it is removed would it be deleted

That would have been the purpose of my question. My case when I want to delete a scene I also want to remove everything with it without further investigation which other scenes or objects or anything else uses those data-blocks. I'm going to edit the original question to make it more clear.

That doesn't make sense.... what if a datablock (a mesh, for example) is in use on another scene - where does that leave that object in the other scene. If you removed the datablock it would leave the object in the other scene without any mesh data - it would no longer have any geometry. Surely that isn't desired behavior? Normally if you don't have anything sharing any datablocks between scenes, removing the scene, saving and re-opening the file would automatically get rid of them. There must be something strange with your project - upload the blend file and we can take a look.


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Is it possible to turn off grid in orthographic view?
Is it possible to turn of only the grid in orthographic 3D Views?

Assuming you have 'Grid Floor' turned off as moonboots shows, there's a quick trick .. when in one of the standard Orthographic Views, tap 46 on your Numpad..(rotating your view by + and - 15 degrees). This converts your standard Orthographic View to a User Orthographic View, from exactly the same angle, and the ortho background grid disappears

Usually you open up the properties panel N and deactivate Grid Floor under Display. However, toggling that property is not supported for orthographic views. Your best bet is the activation of Only Render within the same panel, which basically hides all overlays and visualisations, see the manual.

I don't think this works for orthographic views like top or front like the user asked, I don't think that is even supported

oh ok sorry but he didn't precise it


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Accessing objects and properties in Blender: what's the best practice?
I'm writing a python script that is about to reduce the vertex count of some meshes in accordance with some custom rules (for technical uses, for example, parallel edges must remain parallel and so on).
For this, I need to store data considering Meshes, Vertices and Edges (for example, connecting edges' length for a vertex). It's important that I need to access the containing Mesh from a Vertex or Edge.
My first approach was to inherit a VertexData object from the Vertex where I can add all data needed, like this:
class CustomVertex(bpy.types.MeshVertex):
    def __init__(self, inMesh, inVertex):
        self.data = blabla

But later I realized that this doesn't work too well, for example, I couldn't give more than one parameter to __init__() . (When inherited from a Mesh, __init__() could absorb more parameters).
When discussed here, I was advised to use Properties:
class CustomVertex(bpy.types.PropertyGroup):
    pass
bpy.utils.register_class(CustomVertex)
bpy.types.Mesh.my_vertdata = bpy.props.CollectionProperty(type=CustomVertex)
objdata = bpy.context.object.data
new_item = objdata.my_vertdata.add()

etc.
But when using this, I realized that

I cannot add data to Vertices and Edges this way (only to Meshes, but Meshes allowed inheriting from them, so the first approach was better for this).
I have much more constraints (for example, I cannot sort CollectionProperty like I can sort a list).
My code became much more complicated, I myself cannot read it easily.
I suspect that *Property stuff is useful only when it must be set via UI (most of my internal data doesn't have to be like this).

So, finally my question is: are these my only options for storing/manipulatin geometry/object-related data in Blender? Which is the best approach for this?

A point I don't understand in your question: does the script need to be dynamic? By that I mean updating constantly the mesh when it is modified via the UI for instance? Or it is static: reducing the vertex count after the mesh is stable/statically defined?

Suggest looking at the bmesh module

In an ideal case this could be dynamic. Ideally the user should draw a slider from 4 (minimal count of edges, these stuff are rectangular) to the actual count of the edges. But it's quite a challenge (after removing edges, new intersecting vertices must be calculated and when undoing that remove the new vertices), so as a first version this can be static driven by a parameter (and if result isn't good it can be undone).

In the dynamical approach, will you add or remove vertices to/from the original model?

Anything should work, for example, the script would add a new Mesh tho the model or change the Mesh into the newly created one. Obviously user should see what he/she does, so the original Mesh in Edit mode should be seen. (An even simpler solution would be to only select vertices or edges to delete and remove them manually.)


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Animation flipping (the wrong way) when rotating
I'm working on a Roll animation for my character and it isn't behaving porperly. On frame 12 the "W" component of the "hip" bone becomes negative (using quaternions). Then between the frame 20 and 32 it tries to interpolate towards a positive number, but it flips around the wrong direction. How do I fix this? If that is not possible then what is the best way to handle this kind of animation?

P.S. I'm using version 2.77.

Your issue comes from the quaternion rotation of the hip bones flipping in the W value, as you guessed. The fix here is to negate the W value on frame 40 so that the hip doesn't have to do a full rotation. Setting the Rotation keyframe to [-1, 0, 0, 0] on frame 40 fixes the problem because the W value on frame 20 is -0.961.

Negating the W causes the right leg to flip around. This is a very weird problem, because quaternions should not behave this way. Blender should know how to rotate it properly. Isn't this a bug?

I'm not certain what's happening internally, but it looks like negating the W rotation for both of the foot IK targets fixes the problem as well.


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Why does the leg bone move the whole body?
I have a 3d model

And when I move the Left Leg bone it works fine like this.

But when I move the Right leg bone I get this Problem

How can I solve this???
(Links are Images)

You are using vertex groups to bind armature to mesh : so you'll have to

Delete the duplicated vertex groups
Fix/reassign the needed ones ( Head, Body, Arm_L, Arm_R, Leg_R and Leg_L )
Use only one Armature modifier ( delete the others )

The short answer is, you need to fix the "weights" of your armature.
The following is a bit lengthy, but we need to make sure everyone is on the same page, so just bear with me.
In an armature (the generic term is "rig"), each bone is associated with certain vertices.
Those vertices follow the bone as if they were parented to it.
You can associate ("parent") a given vertex with more than one bone.
To further complicate things, you can specify how much influence each bone has over that vertex.
These influence values are called "weights." Sometimes it makes more sense to think of a bone as "owning" or "claiming" a vertex, so I'll use those terms where they make sense, but they're all referring exactly to "weights." You can think of it like a weighted average, if that helps. For example, if you have a vertex that is associated to more than one bone, the default weights would be 0.5 for each bone. That means the vertex will get its transformation from each bone equally. Half coming from one bone, and half coming from the other bone. Think of this as a 50/50 split. However, you can give the vertex a 0.9 weight for one bone, and a 0.1 weight for the other. That means one bone will influence the vertex's movement much more than the other bone will.
One important "gotcha" in Blender is that there are two ways to deal with weights. In one paradigm, any bone can claim a 1.0 weight on any vertex. So, if you have two bones that both have a 1.0 weight on the same vertex... how much influence does each bone have over that vertex? It's a 50/50 split. If three bones claim a 1.0 weight on the same vertex? It's a 33/33/33 split (one third each). However, what if one bone claims 0.9, another claims 0.2, and a third claims 0.7... that gets pretty difficult to figure out. This is the default way Blender works with weights.
The other paradigm works with "normalized" weights. In the Weight Tools panel there is tool called "Normalize All..." and another called "Normalize." These tools adjust the weights such that no matter how many bones claim a given vertex, the weights for all the bones add up to 1.0 (or 100%). So, instead of one bone claiming 1.0, and another bone also claiming 1.0, they get adjusted down to 0.5 each. This makes the math a lot more intuitive... sometimes. Let's say you have a 50/50 split (0.5) for two bones that "own" the same vertex. If you change one bone's "ownership" to 0.4, where does the extra 0.1 go? It goes to the other bone, which automatically gets set to 0.6 so that the combined weights add up to one. So that one is pretty straightforward, but what if you have a 10/20/30/40 split (0.1 for one bone, 0.2 for another bone, 0.3 for a third bone and 0.4 for a fourth bone, all "owning" the same vertex)? What if you change the 0.4 to 0.5, where does it "take" that extra 0.1 from to keep the combined weights at 1.0? ...there's no telling. It might take an equal portion from each of the other bones... or it might not. It's hard to tell.
Either way, the short answer is: nobody likes weights.
Now for the REAL answer you've been waiting for... All the vertices that are moving are associated with (weighted to, or claimed by) the bone that you're moving. You need to select that bone, then select all the vertices that you want NOT to follow that bone, and set all their weights to zero (0.0).
The first step to setting weights is usually to only set 1 or 0 for each vertex, for each bone. So, you'd select an arm bone, then choose all the vertices you want to follow that bone, set their weights to 1, and set all other weights to 0. Do that for each bone. Make sure that each vertex is only following ONE bone.
Once that's done, you get into the SUPER tedious process of blending those weights across multiple bones. The shoulder area will follow BOTH the arm bone a little, and the neck bone a little. This makes for a smoother deformation when you move the arm. This is a tedious process that very few people enjoy.
Weight Painting is a process to do this kind of blending and weight association visually. Normally, there's a color gradient from red to blue that identifies weights from 0.0 to 1.0. In weight paint mode, you'll use a brush-like tool to paint and blend these colors somewhat more intuitively than picking individual vertices and typing in particular numbers. Sometimes one is better than the other. Which one is better really depends on the person and the application.
Note, that the second step is really only necessary for organic type deformations that need to be smooth. If the first step produces what you want (which might be the case for your low-poly person), then you don't need to do much blending.
Do some research on "weight painting" and it'll get you in the right direction.
I hope that helps!

I weight painted it but it still behaves the same. :(

If you can upload your .blend file, I'll take a look at it in a couple of hours.

.blend file


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How to unlink / remove an object from a scene?
There is an object shared between Blender scenes. So the same object appears more than one scenes (see below).
Is there a way to unlink the object from a specific scene? In my case I would like to remove the Cube.001 from Scene.001.

There is Make Links - Object To Scene command and we can use it to add objects to another scene (see below). So I search for kind of an opposite action.

While the active scene is Scene.001 select Cube.001 and press X. You can also right-click   on the object in the outliner and choose Delete.
Deleting an object only applies to the current scene, any other "copies" in other scenes will still remain there.
You can link the object back to Scene.001 by selecting it in Scene and pressing ⎈ CtrlL->Objects to Scene->Scene.001
You can also remove the object using python, you can type the following into blender's python console or paste it into blender's text editor and click run script. Changing unlink to link will let you replace the object back into Scene.001.
bpy.data.scenes['Scene.001'].objects.unlink(bpy.data.objects['Cube.001'])

blender 2.8. both objects from scene A and B deleted when delete object in scene A.

@Albert looking at 2.80,2.81,2.82 and a recent daily build I don't see that happening. Are you sure you are deleting the object? If you link a collection into a second scene and then delete the object from the collection in the first scene it will disappear from both scenes.

@sambler I'm having the same issue in a new 2.90.1 scene. I added my solution to this as an answer.

@DAG When you create a new scene, you get some options, creating a linked scene produces the effect described. That is each linked scene uses the same object lists, so deleting in one also deletes in each linked scene. If you create a new scene or a full copy this does not happen.

You can simply delete the object, however per sambler's comment, linked scenes will delete the object from all scenes, thus:
On the scene and object to remove, do Relations > Make Single User > Object. Once this is done you can safely delete the object.

This is not working in 2.93(.5).  Consider: New Blender File -> New Scene > "Linked Copy" -> Select Default Cube -> "Object" menu > "Relations" > "Make Single User" > "Object" -> Delete object (hitting "X" key -> "Delete") -> Switch to first Scene.  Expected: The default cube is still in this scene.  Observed: The default cube is no longer in this scene.

These observations apply to version 4.0.2
It depends on how it ended up being linked to the scene.
If it's not part of a collection that was also linked ( e.g. if it was individually spawned from another scene by Object > Link/Transfer > Link Object to scene). Then make single user and delete as explained in replies above or use Right Click and Unlink from the Outliner.
However if it is part of a collection (other than the Scene Collection) that was also linked (e.g. new scene created by New Scene > Linked Copy or via direct linking of a collection to the scene  then it's more complicated since the object is also part of a linked collection and altering the object alters the collection which is shared across scenes.
In that case unlink the entire collection from scene2, go back to scene1 and add/link whatever objects you need individually. Otherwise deleting or unlinking seems to delete the object from all scenes.
Best is to switch the outliner to Scene view and see how objects and collections are linked.

bpy.data.objects.remove(bpy.context.scene.objects[id], do_unlink = True)

Could you elaborate more on this? How to use it, where to paste it? It could not be so clear for everybody.

As far as I understood, you need to do that in Python, right? If so, place it at the point where you need it removed. Replace id with some identifier to actually get the object.
If you need to do that manually, just delete button should work, doesn't it?

I'm not OP of this question. Please add more information with Edit option.

This will remove the object from every scene - the question specifically wants to delete it from only one scene.


text:
How to fill a 3D bezier curve?
If I turn a bezier curve to 3D the surface will disappear. But I need 3D curve because it uses all the 3 axis to define the shape. I tried all the Fill options (Half, Front, Back, Full) but none of those do anything for me.
So how to fill a 3D bezier curve? What do those Fill options do using 3D curve?

I think you want to use a NURBS surface, not a Bezier curve.

For those who got here from Google search and want to fill a 2D curve: Edit Mode > Curve > Set Spline Type > NURBS. Then in the Object Data Properties tab, set Shape to 2D, set a Fill Mode other than "None". Under the Active Spline section, tick Cyclic: U. If it's still not filled, you may need to (also in Edit Mode) do Curve > Toggle Cyclic. A lot of steps for something as simple as a fill, but there you have it. If you import an SVG these settings are already set, but there may be cases when you start from a Bezier Curve and need to convert it.

One more detail to mention - when you Set Spline Type to NURBS, tick the "Handles" option in the Operator Panel to preserve the curve shape. Otherwise, your curve shape gets obliterated into she shape of a polygon (curved shapes disappear).

In 3.1 there is no need to convert to a NURBS, any type works when fill mode and cyclic U are set as explained by Mentalist (snapshot).

What you can do is converting it to a mesh and grid fill the result:

AltC: convert to mesh
CtrlF: grid fill (in edit mode)

You have two options, allowing to tune the resulting geometry:

Giving more or less vertices to the curve
Adjusting the grid fill parameters

Thanks. Unfortunately it means we lose the original bezier curve during the conversion. But as I asked what those Fill options for if we use 3D curve? Because it seems they do nothing.

Fill options are to fill along the curve... at first I misunderstood your question, and provided another one (it is now deleted but I will reopen it so that you can see what it means)

I found a way to mimic what you need, using a mesh that is influenced by a bezier. This is not strictly what you were looking for, as said above, but it could perhaps help you or give inspiration, at least. Or so I hope.
I created a bezier circle with 8 control points (subdivided the default). Flat on the ground, but 3d so, not filled.
Then I created a 8 vertex mesh circle, filled, set a subsurf (level 3) so that it looks like a circle. Each mesh vertex is exactly above each bezier control point.
Then I put an empty where one of the bezier vertices was, and parented the empty to the bezier vertex. Due to the above setup, obviously the empty is also just above the related mesh vertex.
Then I put a hook from that mesh vertex to the hook.
In this way the 3d bezier control point moves the mesh vertex, which looks quite like what you were looking for, at least for this simple example.
see what I mean:

Of course a bezier control points also has handles and those can usually change the shape, and this is not happening here.
Another similar an perhaps easier setup can be made using a lattice deform modifier on the same subdivided 8-vertex mesh circle:

I already gave an answer to another question which (on 2d) uses a similar bezier+empties approach on a different setup: Bezier masks for use with groups of shapes? and there somehow I could setup something similar for handles, too (look for the file linked in comments).

This bad answer was deleted because it was a misunderstanding of the question, but following the comments (in another answer), I reopen it to provide further information about "fill option".
Isolated vertices or lines are not rendered: rendering needs thickness.
From a curve, you have 3 typical ways to give it some thickness:

Using a bevel depth:

Setting a bevel object which have to be another curve:

Or using a 'long' or arrayed object with a curve modifier:

Select the curve turn on 2D in the Ôbject Data properties.
Then from the drop down of Fill Mode select Both.

You do realize that the question was asked almost 5 years ago and already has an answer? More that that, OP specifically stated in the question body why 2D curve doesn't suit their needs.

This answer helped me, thank you!


text:
How to set which graphics card is used by OpenGL render active viewport?
I whan to use 3D View OpenGL render with Blender Render.
I have a laptop with two graphics card.

Of course the NVIDIA card is the superior. I used the Blender Help / Save System Info to check the OpenGL settings. It shows like this:

Does it mean Blender using the (lame) Intel card instead of the NVIDIA card?
Is it possible to switch to the NVIDIA?
It seems there is no option in the User Preferences window to select graphics card for OpenGL. There is only graphics card option for Cycles Compute Device but as far as I know Cycles has nothing to do with OpenGL.

As far as I know there is no way to discretely specify a card for drawing in Blender, it will use whichever is currently used by the system to draw on the active display.

as above, but I think you can disable the unwanted card at operating system level... it should be a right-click option  on the card icon, in the first screenshot. never tried but it could work.

This Looks like standard Optimus setting, which means the os chooses on it's own which of the two to use. When you run an application like blender, on Windows this automatically uses the NVidia card. On linux you'd need to mess with either NVidia prime or bumblebee. But on Windows, as said, the Os chooses based on application demand.

More likely you don't want to disable the unwanted card. I did it and the screen turned to black. I had to restart my computer. According to that description resource link there is kind of a power management between the two GPU. So I can choose the GPU for Blender via NVidia control panel. However I did it before (as far as I remember). But I updated the NVidia driver and it is solved the problem.

According to this article: How to set a default graphics card
you can choose graphics card for an application via NVidia Control Panel. You can find it by right-clicking on your desktop.
You may need to update your NVidia driver (and restart your computer). If everything is OK, Blender system info file will look like this:

How to open two instance of blender and have open gl viewport render on different cards ? Is it even possible ?

I don't think so.


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How to merge vertices by distance or delete faces with zero area?
There is that mesh where we can see there are faces on the edges with zero area.

I guess there should be a function to remove faces with zero area or merge vertices/edge with distance threshold (like in Maya).

Related https://blender.stackexchange.com/questions/6188/clean-up-vertices-edges-with-no-faces

Also the basic W > Remove Doubles is pretty well known


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Is it possible to achive classic Z depth type fog or mist in the viewport (3D-view) in Blender 2.8?
In Blender 2.79 there was a simple Z distance or depth type fog. We only have to turn on in the world panel the Mist option and fine tune the parameters. Ee could see it in the 3d-view.

Is there an equivalent in 2.8? I'm looking for the simpliest (KISS) solution.
Or do we have to use the volumetrics in the 3d-view? I guess that is more complex and time consuming solution.

Since you're asking about the viewport, looks like volumetrics is the only option for now. It's very fast though and easy if you attach the volume scatter to the world shader.

World tab, check "use nodes"
Shader (Node) editor, select world instead of object
Add volume scatter (try density between 0.01 and 0.1) and plug into volume world node.

Doesn't require volumetrics to be enabled in eevee tab; works better viewing with camera. A super-fast hack in the compositor, at least fast in terms of cpu time, using z buffer (z render output -> divide by a two to  four digit number, add a number between 0 and 1, mix with image render output using lighten or screen) doesn't affect the viewport and doesn't work with DOF.
Good luck!

Is there anyway that once you use the volume scatter node to create the fog/depth look to make the background transparent?

@J.Jesse yes, assuming since you're asking about alpha that you want to composite the render with another image source. Posted another answer below for your use case. Also check out the "holdout" shader node to create a "green screen," might be easier to alpha-out the backdrop.

Looks like Mist is back as of 2.82a, enable mist in view layer properties:
Invert the mist output and plug into alpha:
Which will give you alpha to overlay over other renders/photos.
Obviously this example render looks terrible but shows mist-based alpha in action.

This doesn't work in the viewport, only in renders.


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How do I change the direction of an object set to "Bake Sound to F-Curves"?
I have an object set to "Bake Sound to F-Curves" and "LocRot". It's set to move along the z-axis. My problem is that it moves in an upward motion as pictured below. How do I make the object move in a downward motion?

Could you include a .blend file? You can upload it to blend exchange.

Just uploaded a .blend file.

Idle Chit-chat
I assume that by "in a downward motion" you mean that you want its jittering effectively reflected over the x axis. There is a way to do this.
Solution
Go to the Graph Editor, select the baked-sound f-curve, key N to open the Graph Editor's Properties panel, and open the Modifiers drop down menu (it should be at the bottom of the stack). Add an Envelope modifier and change the settings to this:

You will need to click Add Point before you can change the bottom-most settings (1, 0, and -1.8). This should make the cube move in a downward motion.

@cegaton Trial and error. It's been a long time since I learned the modifier and I couldn't remember the specifics.


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bone getting far away when make cyclic extrapolation "repeat with offset"
i don't know how to make the suitable title for my problem here, sorry for that..
the problem is appear when i add F-modifier cyclic (shift E) extrapolation to all bone and make it "repeat with offset" in 3 bone (foot IK L, foot IK R, Torso)
but the foot IK_R have an error that make it stretch or getting far away as the animation getting longer. i think it's due to the y location however i can't trace or even fix the error..
Here is the blend file:

A very old question but I had the same problem in Blender 4.
The final position minus the distance traveled of the bone has to equal zero. Otherwise the difference accumulates.
For example, if your path bone starts at Z == 0 and you translate it to Z == 4, any other bone you translate in the Z direction must also be translated by 4 units Z. Bones that aren't translated must go back to their original position.


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Parts of my mesh are hidden when armature modifier is turned on
I've been following an online robot modelling tutorial and I'm having an issue where part of my mesh is invisible when the armature modifier is turned on. When the modifier is turned off I can see them again.
I had already started animating my model before I realised two of the cylinders on his legs were missing!
I'm new to blender and i'm totally lost as to what the problem might be, any help would be welcome!

Can you include a .blend file? You can upload it through http://blend-exchange.giantcowfilms.com/

Make sure they're weighted properly :-/

I've added a .blend file now

You get a twist problem on your "Track To" constraint on KneeCylinder.L / KneeCylinder.R.
(Try set influence of this constraint, and you will see your cylinder).
Quick fix by Rolling your bone by 180° (edit mode, and set roll to current roll + 180°)

Thanks for the response! I can see how to roll the bone 180°, but how do I set roll to current roll + 180°?

Several ways : * on edit mode, Ctrl+R, and 180. This will add 180 to your current roll. * Or Click on your roll, this will display (for example) 2.5d. Then add +180 to display 2.5d+180, and press Enter. This will add 180° to your current 2.5°

Great! Thank you. Okay, one more silly question. I moved the KneeCylinder.L and KneeCyliner.R bones to a different bone layer and now I can't figure out how to find/select them in order to change their roll.

You can choose what bone layers you want to display on armature properties, panel skeleton

You're welcome. Don't hesite to set my answer "usefull" if this answer your question (as it seems to be)

Problem solved! Turns out the vertex group weights on the mesh were incorrect. The mesh for the knee cylinders was also weighted to the "upper_arm.L", "upper_arm.R", and "rubber_material" vertex groups.
Once I removed the incorrect weighting the cylinders re-appeared.


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Rendered model is skewed and out of shape
I've just started creating the model of a Carom board and it looks fine in the perspective, orthographic views. But, when I render the same it gets skewed up and looks very odd. Am I missing something here?
When "Rendered" is selected, it looks different.

Blend file:


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How is the amount of displacement calculated?
I need to know how blender calculates the amount of displacement it applies to a vertex.
I use the following configuration:

Cycles renderer
displacement node (scale = 1.0, midlevel = 0.5)
8-bit displacement map

What is the minimal and maximal displacement for this configuration?
My assumption (BU = Blender Unit):
Min = scale * ( 1 BU / (0 - 128) )
Max = scale * ( 1 BU / (255 - 128) )
Can anyone confirm my assumptions? Unfortunately, there is no information regarding this topic in the official documentation.
Edit: New assumption with some evidence

convert values displacement map from range 0...255 to 0.0...1.0
displacement = scale * 1BU * (val - midlevel)

Experiment for Evidence:

I have placed a cube beside my flat surface. ( default cube with
edge length of 2BU, therefore scaled z by 0.5)
edited the displacement map -> added a completely white and a completely black area

Result:

As you can see, the maximal displacement is one BU, as the cube is 1 BU in height. With midlevel 0.5 the displacement spans the range from -0.5 to 0.5.