text:
Element indices messed up after switching from Edit to Object Mode
I encounter the following problem. If, somewhere in my script, I switch from Object mode to Edit Mode and back, the indices of the elements in my object become messed up.
To recreate the problem: Create a cube (or any mesh object for that matter) and run the following Python snippet:
import bpy

object = bpy.context.active_object

for v in object.data.vertices:
    print('1',v.index)
    bpy.ops.object.mode_set(mode = 'EDIT')
    bpy.ops.object.mode_set(mode = 'OBJECT')
    print('2',v.index)

I expect the following output:
1 0
2 0
1 1
2 1
1 2
2 2
1 3
2 3
1 4
2 4
1 5
2 5
1 6
2 6
1 7
2 7
1 8
2 8

However, I end up with the following output (the numbers change seemingly randomly everytime I run the script):
1 0
2 123
1 124
2 -166
1 -165
2 116
1 117
2 -164
1 -163
2 153
1 154
2 -162
1 -161
2 182
1 183
2 -160

Does anyone know what causes this problem and how to solve/workaround this? I prefer NOT to use the BMesh module, since the bpy operators suit my needs much better.
Thanks in advance,
Niels

Can only manipulate mesh data (eg me.vertices) in object mode. eg to set a vert to selected in object mode v.select = True then flip into edit mode it's selected. Setting it in edit mode does nada.  Blender makes a (lets call it a) copy and places in edit mode and writes it back when toggling back to object mode. Hence a reference to a vertex before and after will not work as expected. It would be the same case with bmesh.  An object mode bmesh wont pick up any changes if done (after loading)  to the mesh in edit mode and an edit mode one will be dead after the toggle.   This may be a

far more answerable question if you describe what you are intending to do that requires having a vert reference in object mode to use  after a toggle.  If a vert is deleted in edit mode above, the code  would quite likely crash blender.

Thanks for your answer batFINGER. What I intend to do is calculate a gradient for each vertex. So in pseudocode, it would look like this:

For every vertex in object
1a) Select this vertex (v.select = True)
1b) Select neighbor vertices (bpy.ops.mesh.select_more())
1c) Store normal angles
Compare normal angles within selection... etc.

For being able to perform a bpy operator (select_more() in this case) I need to toggle to Edit Mode. While (as you said) for manipulating mesh I need to be in Object Mode. So I constantly need to toggle, right?

No reason an edit mode bmesh cannot be used with edit ops.

I prefer NOT to use the BMesh module, since the bpy operators suit my
  needs much better.

They are not mutually exclusive.
In answer to

1) For every vertex in object 1a) Select this vertex (v.select = True)
  1b) Select neighbor vertices (bpy.ops.mesh.select_more()) 1c) Store
  normal angles 2) Compare normal angles within selection... etc. For
  being able to perform a bpy operator (select_more() in this case) I
  need to toggle to Edit Mode. While (as you said) for manipulating mesh
  I need to be in Object Mode. So I constantly need to toggle, right?

As a simple example, cube in edit mode each vert selected separately and default select more (one face away) called. For the cube this will result in only one vert being unselected.  Note: Select more can also be called with bpy.ops.mesh.select_more(use_face_step=False) to only select via edge connection.
import bpy
import bmesh

context = bpy.context

ob = context.edit_object
me = ob.data

bm = bmesh.from_edit_mesh(me)
print("-" * 33)
for v in bm.verts:
    bpy.ops.mesh.select_all(action='DESELECT')
    v.select_set(True)
    print("Before", v.index, [v.select for v in bm.verts])
    bpy.ops.mesh.select_more()
    print("After", v.index, [v.select for v in bm.verts])

bmesh.update_edit_mesh(me)

Produces output.
---------------------------------
Before 0 [True, False, False, False, False, False, False, False]
After 0 [True, True, True, True, True, True, False, True]
Before 1 [False, True, False, False, False, False, False, False]
After 1 [True, True, True, True, True, True, True, False]
Before 2 [False, False, True, False, False, False, False, False]
After 2 [True, True, True, True, False, True, True, True]
Before 3 [False, False, False, True, False, False, False, False]
After 3 [True, True, True, True, True, False, True, True]
Before 4 [False, False, False, False, True, False, False, False]
After 4 [True, True, False, True, True, True, True, True]
Before 5 [False, False, False, False, False, True, False, False]
After 5 [True, True, True, False, True, True, True, True]
Before 6 [False, False, False, False, False, False, True, False]
After 6 [False, True, True, True, True, True, True, True]
Before 7 [False, False, False, False, False, False, False, True]
After 7 [True, False, True, True, True, True, True, True]

Strongly recommend simply using bmesh for this kind of thing. The linked geometry of an element is readily available.
import bpy
import bmesh

context = bpy.context

ob = context.edit_object
me = ob.data

bm = bmesh.from_edit_mesh(me)
print("-" * 33)
for v in bm.verts:
    # set of all verts surounding based on linked faces
    face_neighbours = {v for f in v.link_faces
            for v in f.verts} - {v}
    # list of edge neighbours
    edge_neighbours = [e.other_vert(v) for e in v.link_edges]
    print(v.index, [v.index for v in face_neighbours])
bmesh.update_edit_mesh(me)

Producing output
---------------------------------
0 [1, 2, 3, 4, 5, 7]
1 [0, 2, 3, 4, 5, 6]
2 [0, 1, 3, 5, 6, 7]
3 [0, 1, 2, 4, 6, 7]
4 [0, 1, 3, 5, 6, 7]
5 [0, 1, 2, 4, 6, 7]
6 [1, 2, 3, 4, 5, 7]
7 [0, 2, 3, 4, 5, 6]

An example to get the angle between vert and edge connected verts' normals
[v.normal.angle(n.normal) for n in edge_neighbours]

Hopefully the examples above might move you a little towards bmesh.  Consider the first example above used on a million vertex mesh, would require two million operator calls, as would the question code.
Python performance with Blender operators
Second example requires no operators, nor does it change the selection state. Actually There is no need to update back to the mesh, or use edit mode to obtain all the info needed for this example
Note worth mentioning for this example could be done in object mode directly from mesh data. Quick python console code example, look for faces that contain the vert index.
>>> me = C.object.data
>>> v = me.vertices[0]
>>> v.index
0

>>> set(sum([list(p.vertices) for p in me.polygons if v.index in p.vertices], [])) - {v.index}
{1, 2, 3, 4, 5, 7}

as in both examples above the only vert not in any face containing vert 0 is vert 6.

Yes, amazing! This is exactly what I meant. Apparently, the BMesh module has more advantages than I thought.


text:
how to set the color on object by program
In python program, I want to randomly give the color to a object, I found a snippet like this
def get_random_color():
    ''' generate rgb using a list comprehension '''
    r, g, b = [random.random() for i in range(3)]
    return r, g, b, 1

bpy.data.objects['object'].color = get_random_color()

however this doesn't work for me, my environment is OSX 10.10 and blender 2.7.6.

Do you want to set the viewport color or material color?

Object.color doesn't work for Cycles Renderer.

Can you add the error message?  The get_random_color() method works fine for me.  Do you have an object named "object"? have you imported random etc.

Your function works generally, but to see the effects, you need to turn object color on:
http://blender.stackexchange.com/questions/7792/how-to-show-an-object-in-the-3d-view-as-a-specific-color

Thanks,@TLousky, it works well for me, could you put the answer, so I can give the reward on the answer

source: Stack Exchange

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

sort: votes


text:
how to import a blender model and manipulate the imported model?
I have a few vehicle blender model files and a ground blender model files separately. the project needs to use python to automatically create vehicle instances onto the ground blender model. To do that, i will need to find blender API to load the vehicle model to ground model through the code.
On the blender api, I need find the
bpy.ops.import_scene.obj(filepath=path, axis_forward='-Z', axis_up='Y', filter_glob="*.obj;*.mtl")

but the API seems to only load the obj model instead of blender model. I want to use blender model is because it also has texture, loading obj model doesn't seem to have the texture loaded. (maybe this is wrong)

Look into bpy.ops.wm.link() and bpy.ops.wm.append(). This is how the GUI transfers objects across .blend files. (To find that out, I used the Python tooltips and hovered over the Link and Append buttons.)

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


text:
Change resolution of the video sequencer preview window
I am using blender as a video editor on a potato. Is there a way to change the resolution of the Video Sequence Preview window without changing the actual size of the window? My computer is super slow and the resolution of the preview window is really bogging my computer down.
If it simply can't be done, is there other ways I could speed up the on-the-fly rendering of the preview window?
Thanks, Max.

Related: https://blender.stackexchange.com/a/33814/26640

You can change the scale of the video preview display by selecting a different zoom level in the view menu. You can also use the mouse wheel to zoom in/out. This may not speed up the video display though as the same video still needs to be read and decoded.

To speed up video editing blender uses a proxy system, which you can find in the Proxy tab of the VSE properties region (press N). Creating a proxy will generate a set of reduced resolution images that will be used for the video preview. When it comes to the final render the full resolution source will be used.

link is currently invalid, is this option still available?

@Omar yes it is still there, I have updated the link and screenshots

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


text:
MBLab 1.7.4 add on refuses to install in Blender 2.8 Beta?
I'm trying to install MBLab 1.7.4b in Blender 2.8 (64-bit, May 24th release.)
I've tried using the standard install from file function, and it doesn't show up in the installed plugins list despite reporting it this summer. I tried the rename step listed here and got nowhere.
Finally I copied an unzipped, renamed copy direct into Blender's addon folder. It showed up in the list of installed addons but it threw the following error when attempting to enable.

Any idea what the problem is?

I had the same issue, and by looking carefully at the log I figured it out.
This is how I solved it:
Install the addon as usual.
In my case, I had it already installed but wasn't showing up in the addon list.
You have to do the "renaming thing" but instead of just renaming the installation ZIP, you have to rename the addon folder that is installed in:
/home/"user name"/.config/blender/2.8/scripts/addons
I renamed it to just MBlab, and that was it. I hope it works for you as well, have a nice day.

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


text:
Modeling a Space Battleship Yamato
I'm modeling my favorite anime of all time. The space battleship yamato or Uchuu senkan yamato(japanese).
I'm having some problem on how to model this ship, from the middle part to the front. Especially the front part with those curved and rounded shapes. I've already modeled some beginners and a bit of intermediate objects so I've decided to give this a shot. Any advice would be a big help to me :)
I'll attach my progress pic as well as a reference pic. Thank you in advanced. Stay safe all :)

I'd suggest to limit the numbers of vertical loop cuts to the same number of vertical lines along side the Yamato hull.
Start with a low poly general shape of the main hull.
Then start to split / separate the parts as new objects.
Parent everything to the main hull
Hide the main hull and start to develop the other objects into their proper shape.
Some details will be external objects placed along side the hull so don't worry in attempting to model the whole ship from a single mesh.
For the Wave Motion Gun you can use a small cylinder and then Joim the mesh with the main hull, bridging edge loops and creating faces when necessary


text:
Is there a tool/option/add-on to generate a polygon circle that intersects the currently selected vertices?
I'm looking for an option or tool or add-on or something that would allow me to create a new polygon circle that goes through the currently selected vertices.
So, imagine you're on edit mode working on a mesh, you select 2 or more vertices and boom!, you get a new circle made of vertices and edges, with the starting vertex of that circle intersecting the first vertex of your selection, the last vertex of the circle intersecting the last vertex of your selection, and if you selected more than 2 vertices the circle will try to intersect them as well.
Is there anything similar to this? How can I achieve this?

Hello :). I'm not sure I understand, perhaps some images would help. But maybe TinyCAD addon is what you want?

Specifically, its CCEN function


text:
Texture Question
Good day
I'm new to blender and the forum, I hope someone will be able to help me.
I want to make something like the picture attached, but only the ball part, not the face and the brain, only the ball wires, where the white wires must be visible, one color and the points between the wires another color, and the black background transparent.
Is there somewhere that I can find a texture like this, or how would I create my own texture?
Any help would be appreciated.

Hi. Please make the title of your question specific to what you are asking and not just the general topic. Thanks.

https://blender.stackexchange.com/questions/28789/create-plexus-plugin-like-effect?noredirect=1&lq=1


text:
Strange deformation on arm - Rigging
Whenever I try to move the arm forwards or backwards this deformation occurs. I've already tried weight painting but the problem still remains. What could it be? Thank you!

Does the mesh or rig have non unit (1, 1, 1) scale?

I'm not sure If I get what you mean. You can take a look at the file :
https://pasteall.org/blend/6aa7698cd9754fc5a3dec3b037fa0ac4


text:
Apply-Scale withouth breaking particles
Is there a way to "apply-scale" to a character who has already been groomed without messing up the particles size? * I’ve already tried "disconnect and connect hair ", it didn’t work. Thanks

Hair systems use velocity values and those values are relative to object size, so I think it will be... er... hairy...  You could try multiplying velocity values by your final scale and then apply scale, but I'm not sure how it will work out.

Actually after a groom I'm thinking those values aren't even able to be changed...


text:
Image in material shrunk after render
I'm modeling a iMac. I did UV mapping for the in screen image and applied image texture to the screen. Everything looks fine on viewport. But when I render the image in the texture shrunk.

I have tried, removing the edges and adding them back in. I have tried creating new texture. Adding new image. Moving the mesh to a clean file. Nothing works.

My guess is you have a subdivision surface modifier tuned down/off in preview, bur on in render. If this is the case, you can fix the image size by adding supporting geometry to the screen area - both horizontally and vertically.

Definitely an issue with subdivision surface. You need to add another loop around the image part of the screen, or you need to mark the edges as sharp.

Yup. It was the subdivision modifier. Just needed remove it, or add in crease around the edge of the image. Thanks, problem solved.


text:
Why aren't these sections mirroring properly?

For whatever reason certain parts of the model won't mirror properly? Like most of the joints and segments mirror fine, and the middle arms mirror fine, but the shields and hands and wrists on the top arms and bottom arms mirror all over the place that don't make sense for x,y or z.
Does someone know why this is happening and how to fix this?

Hello and welcome :). Please add some screenshots to better illustrate your issue. Without that, it's just guessing.

Sorry about that, the picture didn't upload the first time, but it's up now

Hello again :). Try applying your object's rotation through Object > Apply > Rotation.

It seems to work! Thank you! Does object apply rotation reset something?

That's right, it's explained here :) https://blender.stackexchange.com/a/84805/78972


text:
How to cast shadow onto image planes with alpha?

The cube doesn't cast shadow on the leaves but it does on the plane/floor. And the leaves don't cast shadow onto themselves, unlike the one on the top right.
Any ideas?

..my bad, forgot to plug-in DiffuseBSDF. It's working now.


text:
Cycles render showing up black
I am very new to blender (2.81) and have been following a number of different tutorials to produce this file.
Rendered images (cycles) were working fine but suddenly they now come up as black screens. I don’t understand as the rendered viewport view shows everything correctly!
I found a forum help post that gave a long list of things to try and fix this issues and I have attempted tthose I understood but none have worked.
Blend file:
https://drive.google.com/drive/folders/13KHVJxB5VuuFE3hBDRyNraVbIl0MOxwn
If any of you kind folk could take a look and tell me what stupid mistake I have made I would be eternally grateful

There is one large object blocking your view.
In outliner go to MEGACUBE > POOL > Cube.001 and disable the Render Toggle.
You also see the object in viewport if you toggle the Eye icon.

Ahhhhhhhhhhh .... doh! Thank you so much! Sorry for being a muppet! Live and learn!

It happens to all of us :). Feel free to mark the answer as accepted ✓.

omg happened to me too. Was about to ask the same question as I luckily stumbled over this one. thanks!

@Christian Glad this post is still helpful after 4 years :))


text:
Every Material in Viewport is Black, affects EVEE and Material Preview
I am having this issue in EEVEE and Materials Preview where all of my materials are rendering black.
Tried deleting my environment hdri, to deleting all of the lights., seems to be no answer I can find so far.

It appears that you have the only light in the scene turned off. Click the eye icon next to Light and see if that helps. If not, you may need to increase its power. It just may be too weak to illuminate anything.

@Electric_Wizard, thank you for your response. My lights are actually compiled within the scene collection, and they have their proper settings to light the scene. However, if I try to increase the lighting it still doesn't work. I've also changed the lighting type as well as deleting them and adding new lights. It's a really weird issue. I've uploaded my file online and shall post a link on the next comment. Thank you again for your quick response!

link to download file https://gofile.io/?c=zyUkgI

Don't know why, but in order to make this look correct, I had to disable and re-enable the ground collection. This made it render properly in the Eevee viewport for me.

@Electric_Wizard, same for me. It also worked changing viewport shading strength in some situation (but I don't know how to reproduce it).

wow that actually worked  it now loads up, thank you for your feedback!


text:
Hair - Make straight edges

Is there a way to make the hair strands become totally straight ( just like the lines ) and hence get a sharp hair edge with no patches? Thanks

in particle edit mode you can cut and remove hair

@AllenSimpson I tried doing that, but the unevenness still remains. Even with 0 endpoint value it won't get straight.


text:
Paint is going through mask
Is there a way to prevent the paint going through the selected mask?

not really. In wheight paint mode you are a assigning wheights to the vertecies of the mesh. what you see between the vertecies is only colored based on the vertecies around it. so if you have a base mesh with not that much geometry and you have a vertex an you have one in the mask and one outside, blender cant do better that  to make a gradient between them.
hte only way to make that effect less pronouced is to give the wheight paint more vertecies to work with.
If its crucial that you have a sharp edge you could copy it ad apply the subsurf modifier i assume you use. Or dependant on your use cas you could also switch to a texture map instead.


text:
Hair disappearing after rendering
After rendering some of the hair disappear, I'm don't know why only at some parts. The image at the top is viewport and bottom one is render.


text:
Hide object while keeping light reflection
Does anyone know a way to make an object get hidden/invisible from the camera while keeping light reflection on it? Something like a " shadow catcher ", but it only shows light instead. Thanks!

https://blender.stackexchange.com/questions/66026/only-render-reflection-of-an-object-on-an-invisible-object#75626


text:
How to create a false depth effect
I'm looking for help. I'm trying to figure out if it's possible to create "3D" materials in Blender (preferably Eevee). What I mean is that such a material should be able to show features which are offset from the face normals, creating a 3D effect whilst being completely 2D. This is something which is done very well in (my alltime favourite) game, Destiny 2. I think the animation on this page should give you an idea of what I'm talking about! It's mostly used for creating crystals, but also they have large stand-up displays in the game which have the same effect, where moving around the display you can see that the elements on the display are 'deep', giving a similar 3D effect.
I am not even sure where to begin with this. My understanding of materials is decent, but after playing around I haven't been able to find anything. Help would be appreciated!

I think one good avenue for you might be to search on 'parallax mapping'.  This, for example, is a nice page 1.. I wish there was a page 2 in the same style, but there are plenty of other references.

Here’s a related example of parallax fake depth https://blender.stackexchange.com/a/84618/29586 . It’s different to your crystal example but similar principles apply. Also see https://blender.stackexchange.com/a/118394/29586 for use of parallax fake depth.

Thank you both, excellent resources! I will experiment with those, I guess I had forgotten that Blender's vectors may actually be matrices in disguise and therefore need multiplying together, not adding.


text:
Armature twitches out of position for single frame during animation render
I am running Blender 2.82 and rendering with Eevee.
I have a rigged character performing a simple swiping animation with it's arm. The animation plays correctly in the viewport and renders correctly if I render a single frame. However, if I render an animation, the arm will occasionally twitch out of position for a single frame and then snap back to where it's meant to be throughout the animation. If I go back in and manually render the single frames where the arm twitches out of place it will be positioned correctly.
In this manner I'm able to repair the animation, but manually re-rendering a dozen frames over the course of a 9 second animation gets tedious if I have to go back and make changes.
I previously had a similar issue where I was animating render visibility on objects and they would pop back in and out for single frames when I rendered animation, but would remain invisible if I rendered single frames.
Any insight into what might be happening would be helpful.
Thank you.

Thanks @Edgel3D I was unfamiliar with this solution but it worked like a charm! If you want to add it as an answer to the question I'll happily mark it as correct.

Have copied it as an answer thanks @Skelex  :)

I can't speak for vers's 2.8+ but this is a common occurance and the solution has often turned out to be as simple as saving the Blend file, exiting Blender, deleting any cache folder(s) found in both the project folder and Blender's 'Temporary' folder (as designated in pref's), then reloading the project again. Hope this helps in your case... It may also be that the armature is working against some other modifier or constraint


text:
Add a texture (with normal map) to a part of a "complex" object
I would like to set a texture (with a normal map) only on the floor of my model. I created a material and assigned it to the selected faces :

Here are my material nodes :

The result :

You can see my texture on the bottom of the picture but I would like to have my texture everywhere on the floor. Does someone have an idea ?
Here you can download the texture I use : White Marble Square Tiles

Create the UV projection for the floor by Projecting from View from Top View, and then reference that UV map in the Normal Map node - and then also set up a Mapping node before the textures to control the scale of the mapping. Best to also set a Texture Mapping node using UV to the start there.


text:
How to retopologize my model?
The model I make is all messed up and probably has too many vertices. I tried subdividing too many times.

Another helpuful answer can be this: http://blender.stackexchange.com/questions/6253/how-to-convert-from-high-poly-to-low-poly?rq=1

how to did you arrive at this kind of geometry in the first place? do you still have a copy of the mesh in its original higher-poly form?

I don't know.. I lot of strange subdivisions after initially having it quite symmetric. I added the file here: http://blender.stackexchange.com/questions/39750/why-does-my-model-look-patchy-after-i-enable-smooth-shading-on-it

Here's your retopologized mesh.

I'll show you the alternative method to Bsurfaces based retopology. Add a single vertex, enable a snap tool and change a snap element type to Face. Snap the vertex to the mesh and keep extruding it (E) to form a very rough head basemesh. Now make a basemesh model of a body (model it the same way as head). Add a cirle with 8 vertices and keep extruding it to form a tail. Join a body with a head (match the number of vertices and use Bridge tool to join them). When finished delete one half of a mesh and give it a Mirror Modifier.

Use loopcuts (Ctrl+R) to add more geometry to your mesh. Select newly added vertices and snap them to the mesh again. Correct the geometry moving vertices in proper direction. Repeat the process until you get a desired density of a geometry. Use proportional editing if needed. Think of the edge flow. Change it if needed.

Using this method I achieved the final geometry, which I polished a bit (relocated some vertices to smooth the shape and changed the edge flow).

Remember, that you can easily check the errors in geometry (like tris or ngons) using a MeshLint addon (you can download it here: https://github.com/rking/meshlint). After installing it, select the whole mesh (A) and press Select Lint button to display the errors.

TIP: Next time try to start modeling with a very simple mesh. Add a Cube and give it a Subsurf Modifier with subdivision level 1. Apply the modifier, then select one half of a mesh and delete it. Give it a Mirror Modifier and keep extruding vertices until you create a very rough character basemesh (I included it to the .blend file). While modeling try to add as little loopcuts as posible to define the shapes. I guess the biggest mistake you made with your model is you subdivided it too much too early so it lost the proper shape.

Here's the .blend:

Wow that's incredible, thank you so much!! I was wondering what the smoothed kind of paste was around the neck when I enter edit mode? Is that the result of the bridge tool?

@user18623 I don't know what 'paste' you're talking about but I am glad you like it :).

@cegaton I know. Tried to upload via blend-exchange with no results (I don't know what's wrong). I'll try to upload one more time tomorrow.

@Gonzou You said that you used Bsurfaces to do this, I was wondering how difficult it is to use Bsurfaces so that I could learn how to do it? :)

@user18623 I didn't say I used bsurfaces to do it. I used vertex snapping method. Please see this answer: http://blender.stackexchange.com/questions/36525/how-to-easily-make-mesh-retopology to understand how bsurfaces work. I recommend you to use a graphic tablet to have a better control over strokes. A little practice and you'll be retopologizing like a boss ;).


text:
How to fix when riggin the surface is not smooth?
I am rigging my character and when I do the surface becomes all pixelated. How do I fix this?

it seems that your model has not been set as "smooth" shading, but is in the default "flat" shading mode. This can also be driven by the autosmoothing feature (see the "object data" properies panel), if set.

@m.ardito i still get the same problem but a smoother version

if you can share the .blend (eg: http://www.pasteall.org/blend/) I'll take a look.


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how would I change the camera viewpoint or scene object and output the image at the runtime
I have done a 3D parking modeling,  I tried some python code to output the image of the rendering parking, .
output the image
  filepath = self.output_dir + '/images/' + str(i + 1) + '.png'
  bpy.context.scene.render.filepath = filepath

change the viewpoint
bpy.data.objects['Camera'].location = [20,1,0]
bpy.data.objects['Camera'].rotation_euler = [20,30,40) ]

My objective is to let python program collect the images in all camera perspective,  what I can do at the current time is to use the render function during the for loop
  for i in range(0,  car_num):
    self.changeCameraPerspective()
    self.saveLocalImage(i)
    bpy.ops.render.render(write_still = True)

however each new rendering take 2 minutes to load everything from the beginning.
so my question is how to program to make the scene change the camera perspective or modify the object at the runtime (without loading and rendering 2 minutes every time when a small change occurs) , like what we do in the game or 3d modeling?

If you call bpy.ops.render.opengl(write_still=True) it will output the viewport image instead of doing a full render.  This is a lot faster.

@LukasValine I reviewed the code, found i was using the bpy.ops.render.opengl(write_still=True)

@LukasValine my model contains 11 car models, if I reduced the models to 2 or 3, does this will make the rendering faster?

Make sure you're not calling bpy.ops.render.opengl(write_still=True, animation=True).  The animation argument is the only thing I can think of that would make the opengl render take two minutes like you say.

As a side note recommend using scene.camera, ie the one that renders that scene,  rather than bpy.data.objects["Camera"].  And if you are going to change the camera scene.objects.get("SomeCameraName").  You cannot render a scene if the camera is not linked to it.

Well there are 2 options you have here.
1. Optimize all your materials and bake all static shadows. That way the rendering will take as little time as possible.
2. Once you load the scene, move the camera to all locations you want to render but don't render, just add keyframes. When you add keyframes to all locations then start to render the number of frames you need. That way you will only prepare for rendering and load into memory once and then render everything you need in one pass.


text:
save screenshots into local file system in blender game engine in python
In blender render, it is ok to render a scene and save the scene image into the local file system with the code shown below
bpy.data.scenes['Scene'].render.filepath = '/home/user/Documents/image.jpg'
bpy.ops.render.render( write_still=True )

Now instead of working on the blender render, I am using the blender game engine to create a game, the blender game engine is working for me. but I I don't know how can to script to save the game screenshot into the local file system?

This is the same code but for the game engine:
from bge import render

render.makeScreenshot('Screenshot#.png')

On Windows 10 you need to run as Admin to be able to save screenshots to the primary disk.


text:
can't execute the blender python through subprocess
My blender is at the path of '/home/abc/Destkop/blender/blender-2.78'. When command line is at the path '/home/abc/Destkop/blender/blender-2.78', executing './blender -b /home/abc/Destkop/blender/car.model' through command line is working.
I am trying to execute blender in python through subprocess, but the code doesn't work with an error "/usr/bin/python: can't open file ./blender -b /home/abc/Destkop/blender/car.model", but the path is all right
here is my code
import os
import sys
import subprocess

if __name__="__main__":
    os.chdir("/home/abc/Destkop/blender/blender-2.78")
    subprocess.Popen([sys.executable],"./blender -b /home/abc/Destkop/blender/car.model ")

First I expect you should use subprocess.run() rather than popen, which is a lower level call that offers more options that you aren't using.
I would suggest using a full path rather than the ./ prefix to a command.
The main source of your error is your arguments list, the first parameter to run() or popen() is called args and is the arguments used to run the external application. In your case you are passing the path to the current executable, which would be the python interpreter you are running the script in. The next argument is a single string, which python appears to be interpreting as a file path to a script to run.
The arg parameter should be a list of strings that you would use in a terminal, the first string is the executable and each following string would be each option passed to the executable.
By defining the list on multiple lines for clarity -
myargs = [
    "/home/abc/Destkop/blender/blender-2.78/blender",
    "-b",
    "/home/abc/Destkop/blender/car.model"
    ]
subprocess.run(myargs)

The full path can be made more flexible by using bpy.app.binary_path.
You also have a trailing space after the filename which would get interpreted as part of the filename.

thanks, sambler. subprocess is based on python3.5, while my system is based on python3.4 while many packages are based on python3.4

run() was added in 3.5, call() was used before that. Whether you use popen() or call() with 3.4, 3.5 or 2.7, the same applies to the args list that you pass to each method.

The main issue is, the subprocess calls by default do not pass the args through a shell (unless you specify shell = True). Therefore you cannot pass a shell command line, you must pass the individual word strings that the called program would access through the argv vector.

Instead of hardcoding the path to Blender, use bpy.app.binary_path. This is guaranteed to be correct, also on different platforms. I've updated the answer with this, as depending on the current working directory is rather fragile.

@dr.Sybren It would be if they were using blender. I'm sure this script is being run like a shell script to initially start blender.

@sambler oh man, you're right, I didn't even consider that. In that case would the question even belong here? Or is it a generic "how to start a subprocess" question about Python?


text:
how to get 3D vertex bounding box around the object in python
I have a vehicle model, the 3D bounding box of the vehicle model contains the 3D coordinates of each vertex.  My question is would it possible to get the 3D bounding box coordinates, which is a 8 vertex vector [8,2] directly from python. With this bounding box coordinates, I want to do two things, firstly calculate the pose of the object, secondly find a way to calculate the image pixel coordinate corresponding to each 3D vertex.
I have found some related work,
this Save the 2D bounding box of an object in rendered image to a text file shows how to get 2D bounding box coordinates around the image, however it is 2D bounding box.
 Furthermore, Display bounding box around objects
can show us how to display the 3D bounding box around the object, it doesn't tell me how to get vertex in python.

you may be interested in the addon made for this answer.

For the 8 bounding box corners in local coordinates:
ob.bound_box

Transformation matrix from local to global:
ob.matrix_world

Both together:
bbverts = [ob.matrix_world * Vector(bbvert) for bbvert in ob.bound_box]

or
bbverts = [ob.matrix_world @ Vector(bbvert) for bbvert in ob.bound_box]

for versions 2.8 and above.

what I mean is not the x,y,z of the object, but the coordinates of 3D bounding box, which is a 16 elements array of 8 vertex at the corners of the object

I have edited the answer. It is a duplicate of https://blender.stackexchange.com/questions/8459/get-blender-x-y-z-and-bounding-box-with-script.

Should this not be ob.matrix_world * Vector(bbvert)? (@ instead of * in newer versions)


text:
How can I tell if my processor is being fully utilized on renders?
I'm trying to understand how to check if all cores of my processor are being used to render.
I also will be moving to a computer with 2 processors. Does anyone have any experience utilizing 2 processors to render more efficiently?

They are. Look into your task manager.

Another thread mentioned looking into render settings but I guess that's not the case?

In the render settings under the performance tab there is an option that says threads, with auto-detect all the cores will be used, alternatively you can select the amount of cores if you select Fixed.
To check all of your processor is being used just open task manager (Ctrl+Shift+Esc) and you should see 100% cpu usage.


text:
How to assign an image to Image Node by its name
For example I load 2 images (with suffixes: _normal and _color) into Blender.
I'm using this code for importing images:
supported_file_types = '.png', '.jpg', '.tif', '.hdr', '.bmp', '.dds', '.psd'
def path_iterator(path_name):
for fp in os.listdir(path_name):
    if fp.endswith(supported_file_types) and ((bpy.context.scene.color_string) in fp[-10:]) or ((bpy.context.scene.normal_map_string) in fp[-10:]) or ((bpy.context.scene.height_map_string) in fp[-10:]) or ((bpy.context.scene.metallic_map_string) in fp[-12:]) or ((bpy.context.scene.rough_string) in fp[-15:]):
        yield fp

Then I have those images in Image Editor.

How to find imported image by its suffix and assign to Image Node? I can't use the exact name of those textures just suffix, so this method won't work:
image_node.image = bpy.data.images['YOUR_IMAGE_NAME']

you can iterate over the currently referenced images in bpy.data.images.
def get_img_reference(suffix):
    images = bpy.data.images
    for img in images:
        if suffix in img.name:
            return img

img = get_img_reference('_Roughness')
if img:
   image_node.image = img

It's possible to write this shorter but the extra checking is a sanity check. This is case sensitive, beware :)

Thank you, but I don't know the exact name of the textures. I know only the suffix "_roughness".

you may want to learn more about Python string object, it's not strictly a Blender issue. https://docs.python.org/3.4/library/stdtypes.html#string-methods

Thank you so much! It works perfectly. I will check this link.

I have one more question. Is it possible to search only in just imported images? When I use this addon three times I will have three different images but with the same suffix.

not really, you might be able to use the bpy.data.images[0].filepath to your advantage, or make a set() from the names of images present before importing, then do a boolean difference on the set() of image names after importing, and only use the new ones. But this is a separate question which I'm happy to answer If you ask as a new Question (not adding it to this question)


text:
How to set up min/max/default value for node group socket via Python?
Could you tell me how to set min/max/default value for node group socket via Python?
Something like this:

You can access it through the NodeGroup object's inputs:
glossinessFactorInput = bpy.data.node_groups["NodeGroup"].inputs['Glossiness Factor']

glossinessFactorInput.min_value     = -5.0
glossinessFactorInput.max_value     = 5.0
glossinessFactorInput.default_value = 1.5

Thank you. My group is creating by an Operator so it works very well at the first time. When I hit this again button it doesn't work. It seems to work only for group without suffix (.001, .002). Have I put this code under "def execute(self, context):" for an Operator?

If you create a group through an operator, you should also save the created group's name so you can access its inputs. You probably hardcoded the group's name into your code, so you always access the first group and not the later groups you create. Instead of hardcoding the group name, use a dynamic name based on the name of the group you created in your opreator.

Yes, I hardcoded its name. I'm sorry for my stupid question, but how to use a dynamic name?


text:
Forest by particle system and Tree addon?
I try to make a forest.
I built some tree by the Sapling addon, but every each tree are 2 separated objects: the bole, which is a curve, and the leaves, they are planes. The leaves automatically are parented to the boles. I made group from these tree-boles.
In an other layer, I made a plane, subdivided. etc. and in the Particle system tab-Render-Group section i chose this group as source.
But only the boles are disappeared in the " forest". Why can I not see the "children" leaves?

If you grouped the tree with leaves, you choose Group option (as you did, in Render scroll), select this group and check Whole Group option so to use all the elements from group at once, shown exactly as in group.

I am doing that too and I fix it easily by checking the whole group option


text:
Why does background image disappear, UNCHECKED - when the 3d view is closed, re-opened, or duplicated?
I open a blank project, add a background image, and an object.  Closed the 3d-view, opened it again and the background image was GONE.  I revert-to-saved, and image is restored.
This is NOT an ORTHO or PERSPECTIVE issue.  In my screen capture - you can CLEARLY see, on my the bottom window (which I thought was a copy of the same 3d view) - the toolbar, "BACKGROUND IMAGES" is UNCHECKED and the file does not exist.
Re-create problem:
1) open new project
2) Add background image
3) select "3d-view" from the bottom toolbar, where "timeline" defaults to.

The background image settings are saved to the 3DView that the properties region is attached to. By changing another editor to a 3DView a new set of default values are used, they don't get copied from another 3DView.
If you setup the background images and then split the 3DView, then the background settings will get copied to the new editor.

I definately did not know this.  I tested this again, opened my map model - and created 2 3d views - and the map was on both views (after the file was saved, and saw "3" users tagged to the image.  I think after SAVING the file it was stored.  The first two times this happened, I don't know what I hit, since I wasn't expecting the background images (and settings applied to the image) to just vanish from the dialog.

Background images should be uniquely applied to each 3D-view that you want them to appear on, so for example changing your default timeline view into a new 3D-view will not mean that background images are automatically applied to that window. They will however appear in the list of loaded images if you activate the background image and click "Add Image".
On the other hand, if you switch the view mode for one of your 3D-views where you have a background image applied, the background image will stay in place for when you return to the 3D-view in that same window.

I must be doing something wrong.  I had been modeling a map for days, and lost my background images (with all the location, zoom, rotation settings for all the images).  Couldn't figure out what was wrong, had to revert to a saved file and lose last few hours of work.


text:
How do I texture a tree in Blender?
I'm having issues applying a texture to a tree in Blender.
I have tried many different ways to add a bark texture to a tree using the sappling add on, here is the list of things i have tried:
 - I have used the UV unwrap in the modifier menu.
 - I have made it into a mesh by going Alt+c>convert to mesh>unwrap                   and then unwrap it in the image editor.
 - I have mde into a mesh and unwraped it as a cube projection.
What can i do to add the texture without it looking stretched or wierd (by wierd i mean a wierd pattern).
I'm using cycles render, version 2.75.

Welcome! Could you add a picture of the weird pattern? And a picture of your UV map too? Probably your unwrapping is not correct, but some pictures to talnk about would be useful to give you more precise advices.

Probably to unwrap such shape like a tree you shouldn't use Cube Projection, rather than mark seams needed on the trunk and use U > Unwrap.


text:
TexDraw not working
I'm in the process of creating a beach scene, so, in order to do that I modeled some palms, but for some reason I can't seem to paint the texture.
I've created an image, UV unwrapped it and made a node for the texture, I'm using Cycles render.
If I say TexDraw doesn't work I mean, if I click the UV Map/Object in Paint Mode nothing happens, no texture appears.
The Fill and Mask tool seem to be working for some reason.

I have the same issue, did you ever get it resolved?

Have you by any chance added a blank texture under the "Texture" section of the Tools tab?
If you do this, you won't be able to paint anything . . . because it is trying to paint with your (blank) texture.
The way to fix this is to delete the texture from the brush.

Personally I think this is a pretty confusing aspect of the UI . . .


text:
Centering model pivot
I have my model that is not centered and I don'[t know how to fix this because is the first time that I see something like this.. anyone have some idea to how fix this?
I have put it back to 0,0,0 but this is the result, since it's not my model but one that I downloaded from Unity Asset store I'm not the author of this.

Hello and welcome. Please use a title that reflects the content of the question. It should be succinct, unique and identifying, and summarize what the issue is so that users can at a glance broadly understand what your post is about before opening it. Use the [edit] link below your post and avoid any emojis salutations or extraneous text not essential to the question. Remember, your title is the first thing potential visitors will see, and will weight heavily on their decision to open your question, which will directly affect the number of answers you might get.

Select your model in object mode. right click. select “geometry to origin”. that should move model to the center of grid origin and set model origin to center of model.


text:
Mesh: LoopTools is not showing up
When I enable LoopTools in preferences, its as if I hadn't done it. the Edit tab does not show up at the side, my  W hotkey just cycles through selection tools. Yes I am in Edit Mode.
In the video I'll show how its definitely an issue with specifically looptools because other Mesh: plugins do in fact make the Edit tab appear.
I am on Macbook M1 Pro, MacOS Monterey.

You're trying to edit a curve, LoopTools is for meshes

Typically, looptools is accessed via the right-click menu in edit mode (with a mesh selected), however if you are attempting this on a curve, the option will not appear.

As the others pointed out, LoopTools is for mesh objects. In the video when you enable the add-on in the Preferences you even circle your mouse over the word Mesh where it says Mesh: LoopTools.


text:
Delayed reads/writes from external drive from blender 3.4.1
Computer Specs
New M2-8core gpu, MB Air, Ventura 13.2, 16gb ram,256gb ssd.
New external LaCie, self-powered D2 Pro 4tb drive. Rated and verified at 256mbs transfer rates. This is directly connected via USB-C/4. Blender 3.4.1
Problem
Within Blender, any access of the external drive results in 15-30 second delays before the operation is completed and the beachball goes away. Some longer than that.
Both Apple and Seagate (LaCie owners) have failed to provide any insight, just circular finger pointing.
Was there something I should have configured or setup to optimize this?
Any shared experiences or advice would be great. I am a producing 3D modeler, creating 3D printed artwork

Probably the same as this https://blender.stackexchange.com/questions/149926/saving-blend-files-straight-to-server-nets-0-5-speed-of-a-windows-file-copy-ho

Duarte, very helpful.  I am considering keeping working projects on my internal ssd and then doing some housekeeping/archiving once completed. The issue is of course exacerbated by the new Asset Browser feature in 3.x. It wants all the .blender files with assets to be kept somewhere that Blender knows about it.


text:
Modeling a low poly tree
I've been modeling a low poly tree and i was wondering if i could add a branch to the tree without having to subdivide the tree a lot of times, thanks in advance.

PrtSc (top row of the keyboard, to the right of the alphanumeric block) will also do in a pinch.

Cant you add it as separate geometry?


text:
How does Blender process optional arguments to MTL texture maps?
I'm developing a program that outputs object files that can be imported into Blender. The output consists of a WaveFront object file (.obj) with a Material Library File (.mtl) that go side-by-side.
The importing works fine and the textures all show up correctly mapped, however I would like to apply a transformation to the textures so that the scale values don't need to be manually tweaked inside Blender after the import.
Following the specifications for the MTL format (http://paulbourke.net/dataformats/mtl/) the scaling would be transformed by using the -s argument, like below.
newmtl AM_BBAY_WINDOWS_PIRATE
illum 2
Kd 1.000000 1.000000 1.000000
Ka 0.250000 0.250000 0.250000
Ks 0.000000 0.000000 0.000000
Ke 0.000000 0.000000 0.000000
Ns 0.000000
map_Kd -s 1.0 -1.0 1.0 AM_BBAY_WINDOWS_PIRATE.png

Expected behavior: Blender should use AM_BBAY_WINDOWS_PIRATE.png as the texture file and set the material size to 1.0, -1.0, 1.0.
Actual behavior: The size is kept as default and the file is set to -s 1.0 -1.0 1.0 AM_BBAY_WINDOWS_PIRATE.png which obviously is invalid and therefore does not work.
Why is Blender completely ignoring the arguments for texture maps in material libraries for imported objects? Is there another method/syntax for Blender that I've missed?

The .obj importer is written Python, you could have a look at ../scripts/addons/io_scene_obj/import_obj.py. If it's part of the spec, and your file is valid, perhaps a bug report is appropriate.

@zeffii Looking through the file you pointed to, it doesn't seem the MTL importing has any support for texture map arguments at all. Where would one report this?

generally follow the advice on this question: http://blender.stackexchange.com/questions/1377/best-place-to-put-bug-reports

@zeffii Thanks, made a bug report here: https://developer.blender.org/T46459

Thanks for doing the bug report, it seems not many people have needed that feature of the .mtl spec. Generally we close this kind of question because it is a bug report, and there is no obvious solution without modifying the importer code. Feel free to experiment with patching the importer, it's more likely to be fixed sooner by someone with a vested interest.

@zeffii Talk about efficient, they patched it this morning. :) https://developer.blender.org/rBAecdc7c03ec14e6ed70dea808b61049017f46ad97


text:
How can I get the Hair selected hair strands?
I need get/set the selected hair strands, coud it be possible? something like bpy.context.object.select
I can't find it!!!
Thanks a bunch!


text:
Texture Paint and UV map on render cycles disappears after restart blender
I have a problem when using the texture of paint on rendering cycles . I do the mapping texture and works properly . But when I restart the blender , the UV map and texture disappears and the material becomes black . So I have to paint the texture again. Does anyone know how to fix this ?

Did you save the texture file before you restarted blender?

I saved All As blender Project.
I have to save the image separately?

Thank you! I saved the texture paint as image and it was ok.


text:
vertices tracking: movie clip editor
Background:

I've a *.png sequence previously rendered: a moving computer
Now I wanna add the video to the monitor, so need to track the image sequence.
The *.blend file is the same one I rendered before but I don't want
to render the whole scene one more time.

How to use vertices groups previously created (monitor) as tracking points?
Any other solution to solve this job?


text:
Any way to use the timeline markers as input list?
Basically, I have a phrase and want to add a letter every time a marker is met.
i.e. every time a letter is hit while writing a message.
Is It possible to do something like this using the animation nodes?
I found out that the path for them is bpy.context.scene.timeline_markers but don't know how to mix the things together.. ^^"

First, we should get the frames at which the markers are set, to do this, we can use this list comprehension:
[marker.frame for marker in bpy.context.scene.timeline_markers]

Which returns the frames at which the markers were set:

Next, I am going to subtract the current frame from this list, now all the markers that have frame values less than the current frame will have negative values. If I max the output with zero, all the values that were negative will become zero. If I "not" (Invert) the result, all zeros becomes ones and non zeros becomes zeros. If I sum all the values of the output, I will get the number of markers that are before or at the current frame. I can now use this output in a Trim Text Node to show the characters:

Which results in:


text:
Python Script to extrude faces on a plane?
I'm working on a blender project that could be more easily done via a python script. Unfortunately, I don't know much about python or scripting within Blender.
So I've got a plane that's loop-cut-and-and-slid into a 9x7 matrix of  square faces. I need to extrude these faces at different values that can be found on an excel spreadsheet.
I'd like to script this process to start from a face, extrude it the necessary amount (anywhere from 0 to 4.5), and then move onto the next face, extrude it the necessary amount, and on and on until all of the faces have been extruded.
Can anyone assist me with creating this script?


text:
Align object to edge | "Fence-generator"
I want to build a 'Fence-Generator'. For that i did simple path from points connected with edges.
What i did so far:
Aligned fence-poles to verticies and fences-walls to edge centers. but now i want the rotation of fences-walls to match the rotation of the edges.
I tried to calculate the angle but i didn't got it to work.
Any help on how i can calculate the right rotation for the wall would really be appreciated!
Loop Setup for Pole and Wall Generation:

Object and loop initialization:

Current State. I want the walls rotation to follow the edges.

Presuming the base wall object is aligned along X and long 1 unit.
You can have the angle using the angle from the edge to X axis.
So if you have the vector <e1, e2> of the edge, the angle is given by atan2 (arctangent B/A in Nodes) from x, y componants of <e1, e2>.
Note: in the nodes below, have used iterations on object and edges instead of by index access.

Hey Lemon,
Thanks alot! That did it.
Have a nice Day! =D


text:
Exporting Single Frame Animations to .FBX not working. (Blender v2.76b, Bin-Exporter v7.4)
I'm trying to export single frame animations to the .FBX format which doesn't work, maybe I'm doing something wrong.
I'm trying to create multiple single-key animations using the action editor in Dope Sheet and export them to .FBX so I can use them in the Unreal Engine 4. The exported .fbx file has the mesh and armature (skeleton) but no animations, as if they where not exported. I checked this not only by trying to import them to the UE4, but also by checking the file in Autodesk's FBX Converter tool.
The only way I can get the animations to appear is if I toggle the "All Actions" and the "Add Keyframe to beginning and End of animation settings". This results in animations getting exported, but they then consist of 2 keyframes which is unwanted.
So my question is, how do I get single key animations into an FBX file.
Thanks for any help,
I'm using Blender v2.76b and the Binary FBX Exporter v7.4 (also tried the ASCII version, same result)

The question is unclear, to me: you either say "single frame animations" (which make no sense to me) or "single-key animations" (which I don't know about, really, and I never used UE4). Maybe attach an example .blend that you wish to export to fbx, and/or some screenshot to better understand.

I'm talking about single (1) key-frame animations. Which seem unable to be exportable. No animation shows up in the blend file. But I guess it doesn't matter, I've implemented a workaround in the unreal engine, I just remove the other frame manually.

I've just come across this problem myself. Frustratingly, the only way I can get around it is by ticking bake_anim_use_all_bones and bake_anim_force_startend_keying, which increases the size of the fbx 10 fold. For some reason the exporter ignores single frame actions, this seems more like a bug than common sense if you ask me.


text:
Import and exported File have different sizes though they are identical
I have a .ply file which is 6mb in size. It has about 140000 faces. This is an output of a 3d scan. When I import it into blender and export it again as a .ply or a .obj, the file size is increasing to 60mb, even without making a single change (No modifiers, no change in scale, no change in mesh, nothing!). Can someone help me in figuring out why this is happening? Thanks
What is that blender is adding to the imported file to make it 10 times bigger in file size?
Also, i tried decimating the object to a ratio of 0.1 and still the exported file is 9mb, while the original 3D scanned file is just 6mb.

perhaps your 3d scanner is exporting as .ply binary (compact storage), and blender exports as .ply ascii (less compact, but human readable). https://en.wikipedia.org/wiki/PLY_(file_format)

Ohh, may be. Is there a way I can check that?

try look at the .ply in a text editor

This is how it looks like (3d scan output ply):
à²rÂ˜ÓjC2—£Dà²rÂ.¶€CTœ¢D.à²rÂ.û€C
”¢D2à²rÂ°ßsCjU£D(à²rÂüdvCÌ8£D(à²rÂð·mC"‰£Dà²rÂHœpC8t£Dà²rÂ¤€sC

yep, that's binary (not human readable)

Blender's .ply importer can handle two kinds of .ply file.

ascii  (plain text -human readable, but large file sizes)
binary (data is stored in a compact way, and must be decoded before it becomes human readable)

Blender exports neither .ply or .obj as binary, so expect larger file sizes as exports.

Just curious, do you know if there's a converter tool to strip a non-binary .ply down to binary? Because it seems that would address OP's concern with file size, while keeping the essential data intact.

Nope. I don't know of any Blender exporter for .ply or .obj that saves as binary. The question seems to really be why there's a difference in size.

Right, but what I mean is: maybe there is a separate script or app outside of Blender that can take an ASCII .ply and reduce it to a binary .ply. Wait, actually I'll just search online... Hey! Turns out there is a way to convert them :-) I'll post an answer.

When you export a .ply file from Blender it will be in ASCII format. However, you can then open it in MeshLab and re-export it as a binary .ply, which is much smaller.
This page lists instructions for doing this:

Open the original (say binary) PLY file by using File → Import Mesh.
Export this file to the (say ASCII) PLY file format by using File →
  Export Mesh As. Choose PLY file format in the Save dialog.
MeshLab shows a dialog specific to PLY. Here depending on which (ASCII
  or binary) PLY format you want, choose the Binary encoding radio
  button. Your PLY file is converted! :-)


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Is it possible to mimic the 'pin' operation in only one axis
I was wondering if it is possible to pin a group of vertices only in one direction? So I'm trying to do a cloth simulation of a skirt. When I stitch it on the avatar, the skirt starts to slide down. I tried switching off gravity and then simulating the stitching in the first simulation and then switch on the gravity for the second simulation for the skirt to settle. This works to a decent extent but this also results in a slight amount of slip below the waist. I was wondering if I can restrict the movement of the top edge vertices of the skirts only in XY plane so that there is no movement in the Z direction (no sliding or slipping movement)

No, I don't think it is, as far as I know

Yes, this is possible - in a limited way - using 'sewing springs'.
When you create a mesh for a cloth simulation, any 'faces' act as cloth but any edges (without faces) are considered 'sewing springs'. These are edges that connect two vertices that can be 'constricted' by applying a force to draw those vertices together. The idea being that you could create a garment in multiple parts and then use the springs to effectively sew the pieces together around your model.
One useful feature of these 'sewing springs' is that they resist being stretched beyond their original length and we can use this to our advantage.
To demonstrate... starting with a cylinder, in Edit mode, remove the top and bottom faces and use the 'Loop Cut and Slide' tool to subdivide the edges. Select all the vertices at the top edge. You should now have something like the following :

Extrude the selected edges upwards (EZ1Enter). Now remove the faces from the extruded region (select those faces then press X and choose 'Only Faces'. Select the top 'rim' and press Alt+M and choose 'At centre' to merge them to a single point. You should now have something like this :

Add the top vertex to a new vertex group named 'Pin' and set up your cloth sim to enable Pinning, pinned to the new group 'Pin'.
Running the simulation should now result in the 'edges' remaining at a fixed length, thereby preventing the rest of the mesh from falling. The 'cloth will still fall a small distance but this will now depend on the radius formed by the length of the 'edges' - the longer the edges, the less the cloth will 'fall' - therefore, move the 'pinned' vertex further above the cloth (in Edit mode). You should now have something like the following :

Note that this can interfere with Self Collision, causing strange results. This can be overcome by setting the 'pinned' vertex and the connected top row to an additional Vertex Group and use that in the Self Collision settings to exclude those vertices.
Obviously, due to the nature of the pinning and sewing springs this technique will only work when pinning against the direction of gravity.


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OBJ with Vertex Group export and import
I have a problem while exporting and importing vertex groups data through OBJ format. I have certain vertex groups in my object which consist of only single vertex (as shown in the following two images)
Now I export it by checking the 'polygroups' option and the 'keep vertex order'option in the OBJ export options and then import it by checking the 'Polygroups' option under 'Keep Vertex Order' tab in the OBJ import options. I see that, as expected, the vertex order is maintained, but when I tried selecting the vertex groups, I am selecting faces (as shown in the following images). How can I prevent this from happening? Why is the vertex group with single vertex changing into a vertex group with 4 vertices and the corresponding face is getting selected when the vertex group is selected?

Did you by any chance have a subdivide modifier in your mesh prior to exporting? It mat happen that whatever modifier you had was subdividing your mesh and propagating your vertex group assignments to neighboring vertex.

No. I didn't use subdivide modifier, but I subdivided the mesh in edit mode. I have no active modifiers while exporting.

Did you subdivide prior to assigning the vertex to a group or after? Subdividing after might propagate the vertex group to the newly created adjacent vertex .

Oh, let me check that.

I was subdividing before assigning the vertex groups. But like u said, subdividing after creating vertex groups was propagating it to adjacent vertices. This behavior is also seen in my case wherein in spite of subdividing before creating the vertex groups, it is propagating to adjacent vertices upon exporting and then importing.

Have you tried exporting a larger (more subdivided) mesh with more vertex, to see if the vertex group are still exported incorrectly or how it behaves? See if it still expands by just one vertex or if more vertex are incorrectly added to the groups and with what pattern. Maybe OBJ format does not support vertex groups and instead exports as faces, hence the propagation. Otherwise it might be a bug worth reporting in the bugtracker.

Ok, I've just been testing myself, basically it's what I said before. OBJ file format specification probably doesn't support "vertex groups" feature.
There is no such structure or way to store that information in this file format.
What blender does apparently try to map vertex groups to the "poly groups" feature of OBJ. Since polygroups - as the name implies - only stores groups of faces it as a few caveats as it can't unequivocally map vertex groups to faces, so it can't store certain cases like single isolated vertex from vertex groups.
The minimum supported is probably three vertex, which is the least possible to define a face. This is what my four-corner vertex group (to the left) was imported like, two separate meshed with the four corners separated from the main one (colors for clarity purposes).

So short answer is it is not supported, either find another file format that supports this, recreate you vertex groups in your destination application, or fix them by hand there.


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Objects behave as individual objects after joining
Situation
I have about 10 objects in the scene that I appended from another Blender file. I unlinked the group and now all the objects are independent as shown in figure 1. I selected all the objects and joined them using bpy.ops.object.join() and this shows up in the outliner as a single object as shown in figure 2.
Issue
When I loop in bpy.data.objects, I still get the list of all individual objects(printed all the objects names in console), while I have only one joined object (as checked in GUI - figure 2)

I cannot reproduce the problem. Could you add the script you are using to your question ? (I mean the exact sequence, as I have followed the step you indicate in the question and my result is one object in bpy.data.objects)

Before calling bpy.ops.object.join(), try calling bpy.ops.object.select_all( action = 'SELECT' )

Could be an object.users issue. If an object has more than one user it will not be removed from the bpy.data.objects collection, only unlinked from the scene after using the join op. There is a scene.objects collection for all the objects linked to a scene.

Couldn't really find the reason why this was happening. But found a work around for this. Instead of grouping the objects and appending the group and then unlinking the group, I simply appended all the objects individually into the new blender file. Now I join the objects using bpy.ops.object.join() and tada, it works. Now the object count is 1.


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Add loose edges between mutiple edges of different lengths
I'm having a scenario like below. I have one long edge and 3 smaller edges like shown below
I want to add edges between the corresponding edges like this. Below is a picture of what I want when done manually

But when I use bridge edge loops, I'm getting something like this:

My doubt is, is there a way in which I can draw the required edges using a script and not manually?

Bridge Edge Loops will fill that but if empty spaces between those small islands are filled with edges. Do you need edges to converge exactly where the empty space is (located here)? Bridge won't be able to get them like that of course.

I can't fill the empty spaces with edges because I want to keep them separated. So my application is actually adding springs for different cloth patterns. Say if 3 small pieces of cloth are getting stitched to a bigger cloth piece, and I dont want to add these springs manually.


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Render multiple images simultaneously in blender from multple cameras
If I have 2 cameras in my scene, and I want to render images from both the cameras simultaneously and not one after the other, is that possible ?
One alternate option I was thinking of doing was open two blend files and render image from one camera in each blend file simultaneously. But my doubt is can it be done in the same blend file?

why the need to be simultaneous? the render time will be double anyway...?

I am trying to create renders of an object from 6 different views, and I am doing it for many objects. I am using a script. Was thinking of ways in which in can fast forward the process. Just checking if we can do it this way

6 custom views, not from the 6 standard axis like a cubic environment map, I suppose?

@Sum-Al Did you find any solutions for this?


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Cloth - Cloth interactions in Blender
I am trying to run a simulation with cloth cloth simulations. I created two planes,one below the other, joined them along the edge so that it becomes like 'U' folded, then added cloth modifier to this object and pushed it up along z direction. I added a cube with collision modifier. When I simulate, the cloth cloth interactions are not good because of which the cloth pieces cross into each other multiple times. Is there a way in which I can improve the cloth-cloth interactions?

To make the cloth collide with itself in the example you described, enable self collision.

In the Physics context of the Properties Panel it is found in the tab Cloth Collision.

Enable Self Collision and ajust the other values accordingly.
From the Blender Documentation.

Self-collisions
Real cloth cannot permeate itself, so you normally want the cloth to self-collide.
Enable Self Collisions

Click this to tell the cloth object that it should not penetrate
    itself. This adds to simulation compute time, but provides more
    realistic results. A flag, viewed from a distance does not need this
    enabled, but a close-up of a cape or blouse on a character should have
    this enabled.

Quality

For higher self-collision quality just increase the Quality and more
    self collision layers can be solved. Just keep in mind that you need
    to have at least the same Collision Quality value as the Quality
    value.

Distance

If you encounter problems, you could also change the Min Distance
    value for the self-collisions. The best value is 0.75; for fast things
    you better take 1.0. The value 0.5 is quite risky (most likely many
    penetrations) but also gives some speedup.

Hey I tried this out. It's a good solution. Thanks for that. There are a couple of issues though. A distance of 0.8 is quite huge, and it seems like cloth is bouncing off from itself in mid-air. I tried reducing it to 0.6 with higher quality of collision but no luck. Increasing the quality of collision and self collision to 4 also increases the simulation time. Can you think of any other work around?


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What a "linear modifier" does on the sequencer?
When on the sequencer, there's this "Use Linear Modifiers" option.. What does It mean?
by the guide: "Calculate modifiers in linear space instead of sequencer space."
but which is the "sequencer space"? How does It differ?


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Loop cut and slide modifying UVs in unexpected way
I'm bridging two edge loops as shown in the following image:
The upper portion is the UV map and the below portion is the mesh in edit mode. Once after bridging the edge loops, when I'm trying to divide the bridged edge loops using loop cut and slide, the loops are being added perfectly well in the mesh,but in the UVs, they are coming parallel to the bridged edges and not perpendicular as shown in the following two images.
After bridging the loops

After loop cut and slide

How should I correct the UV after loop cut and slide action?

This seems to be a bug of Bridge. If you fill those faces manually with F or with F2 addon then there won't be any problem while loop cutting. Or if you reunwrap again. But if using Bridge what is shown on the screenshot will be present regardless of what way to use for loop cut - Ctrl+R or Bridge options.

This is what is happening (the link has the image) when I manually put a face in the bottom most 4 points to use f2 add-on. https://goo.gl/RMbHzb . The face doesn't form properly in the UV map. One point is at the bottom left corner of the UV map.

@Sum-Al - I can confirm that manual face creation and F2 are working as expected with the UV.  I'm not sure what's going on with your setup.  How did you do your unwrap?

unwrapped by 'project from view' (top view)

@Sum-Al - that's exactly what I used and I had no issue... strange.  The edge loop bridge did exactly as you described though.


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Change origin/pivot point without using 3D cursor (or basically the GUI)
Is there a way we can change the origin or pivot point for a rotation/scaling activity in edit mode without using the 3D cursor, as I'm trying to run blender from a command-line without GUI and hence can't use 3D cursor.

how are you doing the transformations?

I want to scale a group of vertices, but the origin is at the global origin (0,0,0). When I just select the vertices and enter the scale command, the vertices are scaling with respect to the position from the origin, but I want them to scale with respect to the local origin (mean or geometric center of the selected vertices). So I want to shift the origin/pivot from global (0,0,0) to the geometric center of the selected vertices

try this .. bpy.context.scene.cursor_location = (0, 0, 0) in edit and object mode.


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Is there a way in which we can merge two meshes in edit mode?
I have two mesh islands in the same plane which overlap as shown in fig1.
 Now when I go to selection and do "select boundary loop", it selects the full boundaries of both the islands as shown in fig2 . But what I ideally want to select is just the outermost loop of both the meshes combined as shown . For this I wanted to merge both the islands as one island. Is there a way I can do this?

you need to use the TinyCAD addon and its XALL option

Possible duplicate of How to really make it only "one object"

Select one of your squares. Apply a BOOLEAN modifier with UNION.
Make sure the subdivision number is the same, try aligning them vertex to vertex. Use snap if necessary.
Set the boolean operator to UNION and select the second square.
Voilá.
Thank you for your consideration to vote me as the answer by clicking to the left :the icon with a check mark and upvote this answer.
BFCT_Schiller

I don't want to match them vertex to vertex. Then it won't serve my purpose. And using boolean is same as hitting ctrl+j in object mode in my case.


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How to connect a cylinder/sphere to a flat/curved surface surface?
I'm wondering how you would attach a cylinder or sphere to a flat surface in edit mode. There are many instances, especially in SciFi where you need to attach a cylinder or sphere to a flat surface in a clean matter. Like in these images there are many cylinders intersecting curved and flat surfaces. I know in some of these images they probably don't have it connected and instead just pass through each other, but how would you connect the meshes in edit mode?

I voted to close this question because in its present form it is too broad. There are too many ways to attach a cylinder to a flat surface, and the best way to make the attachment in any particular case is likely to be dependent upon the surfaces and the circumstances involved.

There are many ways to do so. But the question is often, is it necessary. Something artist needs the normals of the meshes to behave appropriately and sometimes the effort just don't really pay for the little returns.
On this video the user is creating an emboss effect on a gold bar. There is alot of times he needs to be joining faces in his video. Link below.
https://www.youtube.com/watch?v=O0mkoMkEbc0
Although this maybe about embossing text the underlying method of how to join meshes pretty much applies for all cases.

Select the edges you want to fill.
Subdivide the edge with the lower vertex count to make a closer match the number of vertices.
Press AltF to fill.


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How to set random color to each vertex clump of my model?
I have this low poly tree and I want each isosphere(suppose to be leaves clumps) to be a random color. I don't have the leaves as a separate object, but the clumps of vertices are not connected to the main tree. How would I approach this? I know there is a way to input a random value and then use the color ramp node to determine the colors, but I don't know how to set the individual leaves clumps to random colors. Also keep in mind I'm going to be creating many instances of the tree later on. Thanks for the help!

Are you familiar with Vertex Color painting ?

And do you really want random or random from a palette, like you provide a low and high brightness green and some script can generates Vertex Color layer data for each icosphere based on a random selection from the gradient between the two colors..  -- Truly random colors is probably not so useful? (it might be.. ..)

Yes, I want random from a color Palette or a color ramp node.


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How to add a hdr world background to its own layer?
everyone. I'm have been working on this project and need the hdr background to be on its own layer. I have a bunch of layers that I have put the main objects on and they all have alphas on them so when I go into compositing I just use an alpha over to combine into a single image. The only problem is now my hdr background has turned into complete alpha as it doesn't show up on any of the layers. I would like to have it on its own separate layer so I can add some effects to it in compositing. How would I go about this? Thanks for the help!

If you enable the sky pass for that layer you can get the sky as a separate pass

The way I did this was to do a dummy run render of the camera's motion within the environment on an empty scene layer, with the environment set to be "visible" to camera, and saved this as a file of PNG's.  Then set up your scene proper, set the film to "transparent", check "use environment" on your render layers, and set the environment itself not to be visible to the camera.  Finally, in the compositor, bring the environment back in as an image (set to image sequence), and alpha over the rest of your scene.


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Can you change the color of camera composition lines?
Sometimes, its hard to see the composition lines with white objects in the background. I know it is probably in the themes in the settings I just can't find it.

you change the active object color

or can u plz provide screen shot what basically you need

The option to change the composition lines in the camera is located in the User Preferences Themes tab under 3D View. Its called View Overlay.


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How to color individual polygons in a low poly model?
So I have been working on this low poly project and have most of the modeling done. So, I have begun texturing and ran into a problem. I can't figure out how to color each individual polygon of my model. Here let me explain.

Notice how this image(that I found in a google search) has polygons in the model and it transition from blue to red and even in the blue and red the saturation and brightness changes to achieve a more natural look. Now I understand this effect can be achieved with lighting, but I'm doing a landscape so one solid color will not look good. I'm looking for natural variations in color and can't figure how to color them individually.

Do you want to achieve the same effect like in this question ?

Yes or something similar.

Then I think you have possibility to get desired result using ways from 2 answers in the linked thread - either by code provided or extruding and deleting original geometry (to detach faces from each other). Just don't remove doubles if using 2-nd way.

That looks like it was done using vertex colors.
Go into Vertex Paint mode and apply your colors.  Note that faces will blend colors in a gradient based on their vertices' colors.
Then, in your Blender Render material, select the Vertex Color Paint option.


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How to dynamically paint cycle materials?
I am wondering how you would dynamically paint a cycles material over another cycles material? Basically, interchange the material where the brush touches.I have tried switching between them with the attribute and weight paint but doesn't seem to work.

You can use an image texture that you paint on as a stencil between shaders, and this acts like a layer mask in Photoshop. You can also set up an attribute node and use vertex paint, but the effect there is limited to your geometry.

Note that the answer to this question has important implications if you are someone who is interested in working with game engines. Often times game engines will apply specularity or other things to models based on map textures. This saves them having to calculate material properties on the fly because the data is embedded in the map you provide. If you want to make your models "game engine ready" you will want to learn how to blend textures using these sorts of maps.


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Issue when appending object from another file.
I am trying to append the sky object from here (warning clicking this will directly download the blend file). It is a BGE scene that I got from this post detailing Martin's work on an ocean shader.
Immediately after appending the object though one can notice that it does not look similar to how it is in the original file.

Why is this happening?

Do you have BGE set as current rendering engine in the current file?

Also,if I recognize it correctly the file you are trying to append from is one those realistic real time water demos from Martinsh. If I recall correctly those were some pretty complex files with lots of custom shaders and filters and some scripts and interconnecting parts working together. Removing a single object from context will likely break stuff, and things are probably not gonna work correctly on their own.

@DuarteFarrajotaRamos I have the Game Engine selected and also used Texture for the viewport. I also tried appending everything that is inside the objects folder. Everything then looks fine except from the sky. I thought everything is indeed located inside that folder.

I haven't thoroughly inspected the file but there may be extra python scripts in the text editor that don't get imported from the objects alone. Not sure though


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particle hair comes through mesh even with collision
I am using blender 3.2.1
I have a small animation of a suzanne's head and a hair strand parented to it.
The hair is particle hair. It was made this way: 1) making a curve circle and a path curve, in object data properties Geometry -> object and selecting the curve circle. 2) converting result of previous step into a mesh 3) deleting some vertices 4) Fibermesh in HairNet. (this tutorial "Hair addon blender (HairNet) Part 2" )
My problem is: when suzanne's head moves slowly (+- 15 frames between each keyframe) hair works fine (hair does not come though head), but when the head moves faster (+- 7 frames between each keyframe) hair starts to come through suzanne's ear.
Could you tell me how to make hair collide with suzanne?

I want the hair strand not to come through Suzanne's ear while Suzanne's head is moving fast.
I have ticked "hair dynamics" box. There tried setting a Collision Collection in hair dynamics, but it did not change anything.
I have set a collision modifier to suzanne's head in physics properties. In "soft body and cloth" section I played with Damping, Thickness Outer, Inner, but to no avail.
I am new to blender and I will be greatful for any help
link to the file https://cloud.mail.ru/public/zQk3/AiZjPUZAQ


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Is there a way to have Gismos enabled at startup?
I would like to be able to have "Gizmos" on at the start of Blender, I waste so much time having to turn them on manually every start up.
Is there a addon, or some way to enable Gizmos forever, that I can save in my settings so I do not have to keep doing this? I learned how to use blender in 3.0 and the gizmos were always there and I got used to them, since then, every Blender has not had them.

Gizmos are enabled by default. I might reset to factory settings. How are you turning them on?

As @TheLabCat says they are enabled by default. However, when you have everything set up as you want in a new scene (including all your preferred settings such as render engine, etc.) just use File > Defaults > Save Startup File and you should be good to go.

You can save your startup file:

All settings you set will be saved in it.


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track dropdown for "New Image from plane maker" within Movie clip editor isn't there
I watched this Quick tutorial and followed everything perfectly but when I got to 1:06, I noticed that I don't have the drop down but the guy has it.
And to answer your question, Yes I do have the latest version of blender which is version
3.2.2
My Computer

His Computer

He is running 3.3.0 alpha in that video and I suspect the drop down is a new 3.3.0 alpha feature.

Ah right, thanks @MartyFouts :D


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Convert animated grease pencil stroke into geometry, keeping animation
I have been asked to do several animations of a line that animates onto the screen left to right then kind of vibrates into a piece of handwriting. I did a test which was just one word and I kind of eyeballed it in After Effects. But now they want some longer lines and I'm finding it very arduous and AE is very bad at this, it seems, when there are a lot of control points to edit.
So in Blender, in Grease Pencil, I can make a nice morph between a straightish line and some handwriting but I would like to then apply a Wave warp modifier to it for a vibration effect but this is only available for meshes. If I convert my GP animated line to a mesh I lose the animation.
I thought I might be able to export to Alembic but that doesn't seem to work and it comes back in as an empty object.
Is this is possible in Blender?

Maybe Effects > Wave Distortion is what you are looking for ? Works only in Viewport Shading > Rendered. I don't know much about grease pencil.

In the end I used the sculpt mode to edit it frame by frame and it works OK. Would still be nice to know if you can convert and animated Grease Pencil stroke to Alembic.


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Issue displaying geometry in edit mode
I have encountered a display issue that I am not quite sure if it is a problem or a feature.
Everything works ok in Object Mode, but when I switch to Edit Mode, the geometry is displayed with a kind of double-border (I don't know how else to describe it!), as if the geometry was the bounding box of some some inner volume (see screenshot below).

With just the cube this style of display is kind of workable, but when the scene gets crowded, this feature gets increasingly confusing I suspect this is a display feature, but I cannot find its settings anywhere; also, I could not find any information at all concerning the topic (to be honest, I wasn't even sure of the keyword to search); I only found information about the "Limit Selection to Visible" toggle; but I am fully aware of that feature and it works fine. If this display mode is a feature, does anybody know its use and how to disable it to display a solid geometry in Edit Mode?
I am using Blender 2.76b on Windows 7 with 8GB RAM, AMD and 2GB AMD Capeverde.
Can anybody help? Thanks in advance.
Regards,
Sept

whoa that is really weird

Thank you for your help. On reviewing the post suggested, I found the solution.
It appears that the 3D clipping property needs to be within reasonable ranges, otherwise the edit mode display will be deformed; my viewport clipping ranged between 1 cm and 10 kilometers at the time I experienced the problem; when I dropped the end-clipping to 1 km, the problem with the weird display in the viewport disappeared.
It is interesting to note that exactly the same happens with camera view; if the camera clipping settings are outside a certain range, the geometry will show the double-border in edit mode, although only in camera view.
I found that The clipping range 1cm to 1km in metric (or .001 and 1000 in generic blender units) works well for both viewport and camera views.
I hope this information is of use.
Regards,
Sept


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How to create a sub-category or folder in T-Panel tab
I used to have a problem with the clattered tabs in my T-Panel, but not anymore since I discovered how to edit the code of a tab in the T-Panel (rightclick in any button of the tab contents and select "Edit Source") and finding the "bl_category" value in it and change it to create a new category or to move the item to an existing one. This works beautifully, but I have a problem; some addons have several components and I would like to group those in a "sub-category" or folder (I am not sure of the right term).

For example, I have organized all the addons into a number of tabs (see screenshot); including a Misc tab, where I include all the new addons that don't fall into any other category; in Misc I have the "Mesh Align Plus" add on which is made up of six quicktools entries; I would like to group those six entries into a single "Mesh Align Plus" category of its own within "Misc", creating a kind of folder.
Is that possible at all?
Thanks in advance.
Sept

nested collapsible layouts are - as far as I am aware - at the moment unsupported. You can only segment in tabs and panels currently.

The sections you are referring to that can be collapsed and expanded are called panels. You may have noticed that when you alter the addon you find the bl_category a few lines under a class definition that has Panel in brackets at the end of the line.
We have some control over the placement of panels (not 100%). The small dots to the right of the panel allow us to drag them up and down to get a different order and the order that we place them in gets saved with the rest of the interface settings. This means you need to enable the addons that you want, Save User Settings so that they are enabled on startup, then re-arrange the panels the way you want them and then File->Save Startup File so that the layout settings are used every time you start blender. You may also want to ensure the Load UI option under the File preferences is disabled so that your startup layout is used instead of the layout saved with the file.
To get more than that you will need to write your own addon. Yes you can copy the code of another addon, but the changes needed mean that you will need to re-structure the code again after any updates - so consider this option as your custom addon where someone else writes most of the code for you.
Each panel is defined by a class that is a subclass of bpy.types.Panel. The draw method of the panel class defines what is displayed inside the panel, you can take the contents of an existing panel's draw method and combine them into one panel that you have defined. For some panels you may also need some of the surrounding code that the panel relies on. As shown in this answer you can add a custom property and use that to show a disclosure triangle that can contain the items from another panel to get the "sub-folder" layout that you are looking for.
You can find an example addon here that provides the following panel.

Thank you for your answer. But my question is, more specifically, if I can create sub-category within the Misc category in which to contain the several entries of a single addon. Regards, Sept

@Dunno - I have expanded the answer to include an example of making your own addon.

Thanks a million, sambler; that helped a lot and certainly answered my question; and my apologies for posting in the answer, rather than in the comments, section. Sept


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AO baking for modular environments that will be moved/rotated?
I need help in baking in such a way that my modular environment will line up regardless of direction or position. Can it be made internally or do I need xNormal or similar?
(Images are with diffuse on top)

Maybe you could change the AO distance to avoid that the shadows reach the border of the assets.
Go in Blender Render mode, in the World tab, search the Gather line and reduce the Attenuation Distance Value:

Even if the option are grey they will change the AO, also they work for Cycles.


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how to intertwine two strings together into a single string
I was able to make the rope, but the result was bad, does anyone know how to make power by the function of the modifier?

maybe this will help? https://blender.stackexchange.com/questions/114563/how-to-create-twisted-wires-in-blender/114566#114566

I appreciate the indication, but it's not what I'm looking for. Notice that my only more complex objects, they are already twisted, I need to twist something already twisted, you know?


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Motion Tracking: status of tracked pattern in a python variable (tracked vs. not tracked)
Is it possible to have the status of a tracked pattern stored in a python variable (per frame)? For example, a pattern is successfully tracked for some frames, then the pattern is hidden behind something, afterward it is visible and successfully tracked again. Would be great to use the status of "actually tracked" vs. "pattern lost" in my python script.

The status of a track (actually tracked vs. pattern lost) is available (per frame), stored in a property called mute. If the pattern is successfully tracked in a frame, the status is FALSE, if the pattern is lost, the status is TRUE.
The status of a track is available via bpy:
bpy.data.movieclips[NumberOfMovieclip].tracking.tracks[NameOfTrack].markers.find_frame(FrameNumber).mute

As far as I am aware, this is not possible. You could probably edit the C source code to output these variables for use in your script if you wanted to though.
You can view the Python API section of this page to make sure if you want.


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Water in a glass bottle error
I'm having a bit of an issue trying to simulate water in a glass bottle. For some reason there seems to be some refraction that causes the water to bend upwards and creates a weird effect(a sort of upwards bump).
Can anyone please shed some light on this situation and explain why this is happening?
I have also attached the blend file below:
https://onedrive.live.com/redir?resid=6385EC1FC28C8087!337&authkey=!AGWj45uZHzTciRo&ithint=file%2cblend
Thanks.

That all looks physically accurate. Realize that the bottle acts as a lense, so it distorts things behind it

While I understand that some distortion should occur, I have seen other results on the internet that don't have that weird bump. Scaling the water object doesn't work.

Ah, I think that is a reflection on the bottle

Reflection? I don't quite follow. Is there any way to get rid of this reflection? Thanks.

What is happening is completely expected given your scene. I think you should instead focus on replicating a product photography scene. Cycles is a physically based render engine, so things work best if you don't try to fake basic things like reflections.

Hmm, I thought I was replicating a product photography scene. Thing is, I'm not trying to fake reflections. I did change the IOR of the glass shader to that of water. However, all I can think of at this point is that perhaps I should try another shader to simulate water, but even mixing different shaders like diffuse and transparency do not give convincing results.

Hi, could you please upload your blend file to BlendExchange? We prefer that you use this, because the files don't get deleted, so people who find your question later can still use all of it. Thanks! :)

@NᴏᴠɪᴄᴇIɴDɪsɢᴜɪsᴇ is right, those refractions look normal to me.

If you don't like them, perhaps adding a backdrop will get something closer to what you want. Here's an example render

What seems to be happening is the light is hitting the bottom of the glass, going through it, and then reflecting upwards hitting the top of the bottle, creating a weird reflection. The reflection changes based on the angle you look at the object.
I'm pretty sure that this is working how it's supposed to. It just looks weird to the eye. There are a few things you could check/do to fix it though.

Check to see if the liquid, is touching the glass. This is known to cause artifacts.
You could change the camera position or lighting to make it less
apparent.
You could also adjust light bounces in the light paths drop down in
the render panel. (this would decrease the realism, but you could lower the bounces so that the light doesn't reflect enough times to cause that reflection)

I think you might benefit from this tutorial. I linked it at the point where he started doing the liquid.


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VSE snap a strip to the begining of your editing
In the VSE is there a way to snap strips to the begining of your editing? For example you've deleted the first strip of you editing, your editing now starts at frame 200 and you want to move all of your strips to frame 0 or frame 1, is there a simple way to do that snapping to the begining of the VSE?

Surely you can just select all the strips, move the scrubber to where you want to snap, and hit Shift+S?

That will only work for one strip with the desired result...

Group all of your strips (Make them a Meta Strip Ctrl+G) and then with your current Frame being 1 (position the green playhead) press Shift+S to Snap the Meta s to the beginning. Alternatively set the Meta Strips Start Frame to 1. Then UnMeta/ungroup the Strip again: Alt+G.

I would select all clips and press G-200 (if your edit starts at frame 200). This will move all clips 200 frames to the beginning of the timeline.
If you have Sync Markers enabled (View > Sync Markers), the selected markers will move with the clips.
To select all markers press A with your mouse over the timeline.

Related: http://blender.stackexchange.com/a/47750/2843

The Extra Sequencer Action Add-on has a Ripple Delete feature. With that you can just create a Dummy Strip (like a Color Effect Strip) from Frame 1 to the Frame before the rest of your footage that you want to move. And then perform this Ripple Delete on that Dummy Strip which should move the rest of your strips afterwards to the left including the Keyframes, etc...