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How to link two objects so that when changing one the other also changes, but they stay separate objects?
I have 2 objects that I want linked to have a modifier apply to A with B. I don't want to apply the modification yet so I would like to link them together so that when scaling A, B will scale the same way. Is this doable through a parrent type relationship perhaps?
In my case I want to have the cilinder object be scaled the same way as I would scale the mesh under it. If I widen or lengthen the mesh I want the cylinder to mirror that exactly, in this case it's for a boolean operation so that might matter also in what is possible to do.

Select both of them and scale? or simple Parenting works. or  parent both objects to an empty .

Right that would work however if I have the top one set to invisible and don't want to keep going back and forth to make it visible ? It's not really a solution to what I want to do, it's a workaround ....

This can be done using Geometry Nodes. I crated a node setup, where the cylinder on top of the box only scales in X-direction if the box is scaled:
Demo video on YouTube
Node tree:

To do this do the following:

select the cylinder
Change to geometry editor
Add new geometry node to the cylinder
Drag an drop the cube from the scene tree into the geometry node editor. This will create a "Object Info" node with reference to the cube.
Add other nodes according to what is posted here.

You can restrict the axis of scaling by routing only one or more axes between the "Separate XYZ" and the "Combine XYZ" nodes. Connecting all three axis will scale along all axes, interchanging the axes will scale the cylinder into another direction - say Z when scaling the cube into X

Seems that setting the parent of the cilidner to be a mesh does exactly what I needed ... Scaling is applied and the cilinder can be made invisible.


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What does the mixRGB node do in Dodge mode?
Can someone explain to me or point me to the documentation of the MixRGB color dodge mode? I've found the documentation of the MixRGB node but could not find an explanation to what the color dodge does. I'm following along a tutorial and I want to understands what is happening.

Just a bad idea to use a broken tool in a radiometric-like model such as that with rendering. It should have been removed, disabled, or fundamentally altered for use in rendering.

From wikipedia, "Blend modes" page: "The Color Dodge blend mode divides the bottom layer by the inverted top layer."  Perfectly precise, and I'd expect Blender to be doing that, atlhough I haven't tested.

@troy_s I'm afraid I don't understand what you mean

The formulas for Dodge and Burn come from Photoshop, which in the context is very anachronistic. They are designed to work on values that do not represent light, but rather encoded values. Worse, they are designed as display referred formulas, meaning 0-100% display encoded values. This means they are completely incompatible with how render engines process light.

source: Stack Exchange

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

sort: votes


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Moving vertices in a way to preserve their relative position from eachother
How can I move the vertices in the picture in a way that they "stretch" and keep their position relative to each other? I'm interested so that I would end up with a consistent geometry from left to right lets say. I could of course just remove the vertices and create a plane but I'm interested in knowing how to perform the transformation while preserving the grid shape.

It seems I have figure out one way to do it, and that is by using a lattice and a lattice modifier. By adding the lattice modifier to the scene, then selecting the object to modify > shift and select the lattice > ctrl +p > deform by lattice, this added a lattice modifier to the mesh and used the selected lattice object. By manipulating the object, the mesh is then manipulated while the vertex grid remains uniform.
You can see in this gif how this is done and looks like (https://gph.is/g/Z7G7JAP) The gif was too large to upload it here.
Another thing that could be usefull for anyone, would be proportional editing mode for this too.

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


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Bodies linked with a Rigid Body Joint are detaching by itself in simulation
I have two rigid bodies (they both are small hierarchies actually) and attached them to each other using a 6dof joint with all limits locked to zeroes.
One of the bodies is controllable with left-right keys, there is a motion actuator that does simple rotation.
I start a simulation, do the rotation, wait 5-10 seconds, and the joint detaches by itself. The second body stands still in the air.

The scene file is here download blender scene

Ok, I found it. I had to set "No Sleeping" flag in the Physics properties for each of the rigid bodies.

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


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What's right topology for a concave polygon?
I have a problem with the topology of a concave corner in a text I have traced. The corner must be sharp so I placed some proximity edges to avoid the subsurf modifier smoothing.
This is how I managed a convex area. I don't know if the topology is correct, but I don't have any problem:

I tryed something similar in a concave area, cutting through one more loop:

When the subsurf is applied, the result is really bad. It seems like there is a hole somewhere, or some rogue faces, but it's not. Everything is "ok".

I can't understand why this happens. It's even all quads.
There is clearly something I don't understand, so I hope to receive some help.
Thank you in advance :)

i think it's your diamond quad that's causing the problem.  Maybe add some supporting loops to stop it from collapsing on itself.

@Xtremity yes, like you said, the diamond shape is the cause of the problem, but I'm not able to stop it. I could cut all the way through the opposite edge, but it's something I would want to avoid. I really can't understand why this happens. The geometry looks legit to me.

If I understand you correctly you want to get rid of the soft edges that are produced by the subsurf/multires modifier? You may want to look if you can fix that by setting the mean crease in the object's option bar to 1.
You possibly need to play around with the value for different edges but usually it gets the job done.

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


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BMesh polygons with holes
Is it possible to create a BMesh polygon (BMFace) with holes via Python?
Use case. I need that for my addons that import geographical data. A polygon for Rome has a hole for Vatican City.

BMesh operator bmesh.ops.triangle_fill does the trick:
bmesh.ops.triangle_fill(bm, use_beauty=True, use_dissolve=False, edges=outer_and_inner_edges)

Here outer_and_inner_edges is the list of BMesh edges (both outer and inner) that constitute the polygon with holes.
The operator will create a bunch of triangles that cover the polygon in question.

Polygons in Mesh or BMesh aren't permitted to have holes in the sense of providing a perimeter and adding an internal part to subtract. This means considering alternatives.

You can construct an irregular polygon / Ngon.

But it will contain at least two duplicated vertices for that pathway between the cutout and the perimeter.

You could script a mesh.fill(), which could take two given edge outlines and fill from the outer edges inwards. (will add script when I have time)

Alternatively you might use a counter intuitive solution namely a 2D Curve (of straight parts) : code included in link

The solution with the pathway could be tricky to realize for a general case:   concave perimeter, multiple concave holes.

How would you script that mesh.fill() for the general case:  concave perimeter, multiple concave holes?

I had to switch off the computer for an electric storm, maybe I can answer later.

yes, is possible.. you need your vertices and faces data...
here a fast template, you only need to modify your vertices and face data:
this addon set a button in order to add some cube with hole:

bl_info = {
    "name": "bmesh with holes",
    "author": "Diego Quevedo",
    "version": (1, 0),
    "blender": (2, 7, 3),
    "location": "View3D > Add > Mesh > bmesh",
    "description": "Adds a new Mesh Object using bmesh",
    "warning": "",
    "wiki_url": "",
    "tracker_url": "",
    "category": "Add Mesh"}

import bpy
from bpy.types import Operator
from bpy.props import FloatVectorProperty
from bpy_extras.object_utils import AddObjectHelper, object_data_add
from mathutils import Vector

def add_object(self, context):
    edges = []
    verts = [(1.0, 0.9999999403953552, -1.0), (1.0, -1.0, -1.0), (-1.0000001192092896, -0.9999998211860657, -1.0), (-0.9999996423721313, 1.0000003576278687, -1.0), (-0.7993143200874329, 7.718172128079459e-07, -1.0), (-0.7839558124542236, -0.1559378057718277, -1.0), (-0.7384703755378723, -0.3058837354183197, -1.0), (-0.6646059155464172, -0.4440747797489166, -1.0), (-0.565200924873352, -0.5652002096176147, -1.0), (-0.44407564401626587, -0.6646053194999695, -1.0), (-0.3058846890926361, -0.7384699583053589, -1.0), (-0.15593880414962769, -0.7839556336402893, -1.0), (-2.6044966716654017e-07, -0.7993143200874329, -1.0), (0.1559382975101471, -0.7839557528495789, -1.0), (0.3058842122554779, -0.738470196723938, -1.0), (0.44407519698143005, -0.6646056175231934, -1.0), (0.5652005672454834, -0.5652005672454834, -1.0), (0.6646056175231934, -0.44407519698143005, -1.0), (0.7384701371192932, -0.3058842122554779, -1.0), (0.7839557528495789, -0.15593838691711426, -1.0), (0.7993143200874329, 6.034655086750718e-08, -1.0), (0.7839556932449341, 0.1559385061264038, -1.0), (0.7384701371192932, 0.30588433146476746, -1.0), (0.6646056175231934, 0.44407519698143005, -1.0), (0.5652005672454834, 0.5652005672454834, -1.0), (0.44407525658607483, 0.6646055579185486, -1.0), (0.30588436126708984, 0.7384701371192932, -1.0), (0.15593849122524261, 0.7839556932449341, -1.0), (0.0, 0.7993143200874329, -1.0), (-0.1559372842311859, 0.7839559316635132, -1.0), (-0.3058832585811615, 0.7384706139564514, -1.0), (-0.4440743327140808, 0.6646061539649963, -1.0), (-0.5651998519897461, 0.5652012825012207, -1.0), (-0.6646050214767456, 0.4440760612487793, -1.0), (-0.7384697794914246, 0.3058851659297943, -1.0), (-0.7839555740356445, 0.15593931078910828, -1.0), (1.0000004768371582, 0.999999463558197, 1.0), (-0.9999999403953552, 1.0, 1.0), (0.9999993443489075, -1.0000005960464478, 1.0), (-1.0000003576278687, -0.9999996423721313, 1.0), (-2.6044966716654017e-07, -0.7993143200874329, 1.0), (-0.15593880414962769, -0.7839556336402893, 1.0), (-0.3058846890926361, -0.7384699583053589, 1.0), (-0.44407564401626587, -0.6646053194999695, 1.0), (-0.565200924873352, -0.5652002096176147, 1.0), (-0.6646059155464172, -0.4440747797489166, 1.0), (-0.7384703755378723, -0.3058837354183197, 1.0), (-0.7839558124542236, -0.1559378057718277, 1.0), (-0.7993143200874329, 7.718172128079459e-07, 1.0), (-0.7839555740356445, 0.15593931078910828, 1.0), (-0.7384697794914246, 0.3058851659297943, 1.0), (-0.6646050214767456, 0.4440760612487793, 1.0), (-0.5651998519897461, 0.5652012825012207, 1.0), (-0.4440743327140808, 0.6646061539649963, 1.0), (-0.3058832585811615, 0.7384706139564514, 1.0), (-0.1559372842311859, 0.7839559316635132, 1.0), (0.0, 0.7993143200874329, 1.0), (0.15593849122524261, 0.7839556932449341, 1.0), (0.30588436126708984, 0.7384701371192932, 1.0), (0.44407525658607483, 0.6646055579185486, 1.0), (0.5652005672454834, 0.5652005672454834, 1.0), (0.6646056175231934, 0.44407519698143005, 1.0), (0.7384701371192932, 0.30588433146476746, 1.0), (0.7839556932449341, 0.1559385061264038, 1.0), (0.7993143200874329, 6.034655086750718e-08, 1.0), (0.7839557528495789, -0.15593838691711426, 1.0), (0.7384701371192932, -0.3058842122554779, 1.0), (0.6646056175231934, -0.44407519698143005, 1.0), (0.5652005672454834, -0.5652005672454834, 1.0), (0.44407519698143005, -0.6646056175231934, 1.0), (0.3058842122554779, -0.738470196723938, 1.0), (0.1559382975101471, -0.7839557528495789, 1.0)]
    faces = [(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19), (0, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 4, 3), (36, 0, 3, 37), (0, 36, 38, 1), (1, 38, 39, 2), (2, 39, 37, 3), (36, 37, 39, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55), (36, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 40, 38), (28, 27, 57, 56), (29, 28, 56, 55), (27, 26, 58, 57), (30, 29, 55, 54), (26, 25, 59, 58), (31, 30, 54, 53), (25, 24, 60, 59), (32, 31, 53, 52), (24, 23, 61, 60), (33, 32, 52, 51), (23, 22, 62, 61), (34, 33, 51, 50), (22, 21, 63, 62), (35, 34, 50, 49), (21, 20, 64, 63), (4, 35, 49, 48), (20, 19, 65, 64), (5, 4, 48, 47), (19, 18, 66, 65), (6, 5, 47, 46), (18, 17, 67, 66), (7, 6, 46, 45), (17, 16, 68, 67), (8, 7, 45, 44), (16, 15, 69, 68), (9, 8, 44, 43), (15, 14, 70, 69), (10, 9, 43, 42), (14, 13, 71, 70), (11, 10, 42, 41), (13, 12, 40, 71), (12, 11, 41, 40)]

    try:

        mesh = bpy.data.meshes.new(name="New Object Mesh")
        mesh.from_pydata(verts, edges, faces)
        # useful for development when the mesh may be invalid.
        # mesh.validate(verbose=True)
        object_data_add(context, mesh, operator=self)
    except:
        print("error")

class OBJECT_OT_add_object(Operator, AddObjectHelper):
    """Create a new Mesh Object"""
    bl_idname = "mesh.cube_hole"
    bl_label = "Add Mesh Object"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):

        add_object(self, context)

        return {'FINISHED'}

class OBJECT_OT_add_objectPanel(bpy.types.Panel):
    #bl_category = "NN"
    bl_space_type = "VIEW_3D"
    bl_region_type = "TOOLS"
    #bl_context = "editmode"
    bl_label = "ADD_OBJ"
    @classmethod
    def poll(cls, context):
        return (context.mode == 'OBJECT' or context.mode == 'EDIT_MESH' )

    def draw(self, context):
        layout = self.layout

        row = layout.row(align=True)
        row.operator(OBJECT_OT_add_object.bl_idname) #THE OPERATOR

def register():
    bpy.utils.register_module(__name__)

def unregister():
    bpy.utils.unregister_module(__name__)

if __name__ == "__main__":
    register()

Link only answers are discouraged as if the link goes down then so does the answer. Please include some of the steps within the answer itself.

@vvoovv I update the answer with some fast addon template that you can use

@yhoyo I tried your addon. That approach could be very tricky for the general case: concave perimeter, multiple holes

This doesn't appear to answer the question


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Shader Nodes: how to use instancer's vertex attribute to get different colors for instances
I want to apply a color defined in the instancer's vertex attribute my_color to get the same color for the related instance. It does not work in the simple setup that I will describe below.
I created a Blender object Verts that consists of 4 vertices. The object Verts will be used as an instancer.

I created an attribute my_color (domain:Vertex, data type: Color) for the object Verts and set some values for it:

I parented the object Cube (the instance) to the object Verts and set the instance type to Vertices

I created the following material for the object Cube (the instance):

The colors from the attribute my_color of the object Verts (the instancer) aren't applied to the object Cube (the instance).

How to solve this task?

This feature isn't supported yet according to https://developer.blender.org/T98437


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Light Groups in v2.73
I want to make an object be affected by specific light sources. How can I make that happen? From what I've read, older Blender versions have it laid out in the Materials and Render Layers tabs.

I don't think this has changed - just double check that you are using Blender Render and not Cycles (since Cycles doesn't have light groups at all)

@GregZaal is correct. there is no possible way to do this in cycles. just like for a while you could not make smoke or fire in cycles, it is the same here. (It is possible they will be re-creating light groups for cycles in the future though)

Related: http://blender.stackexchange.com/q/983/599


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Cell fracture makes textures low res
So I have a simple asteroid model I'm trying to fracture with cell fracture, see here:
However, when I do a cell fracture (default settings), the result looks like this:
But not always! I've gotten it to work twice before, but I have no idea why it worked then and not any other times. Am I missing something obvious? I've spent a couple of days trying to solve this, and I can't find any other threads about it, so I'm totally at a loss.
Assets come from Unity's SpaceShooter demo.

I imagine that cell fracture is trashing the UV Coordinates.  Most generative tools will damage them.  I'm not sure there is a way around this problem since after using Cell Fracture you now have several new models that all have geometry that was never mapped to the original image.

No, that's not right, because cell fracture is supposed to retain UV. It actually works properly sometimes (e.g. with a simple cube), but mostly I can't get it to work at all (textures get messed up).
Out of probably a hundred attempts, two have properly retained the UV post-fracture, but I have no idea why.

as a workaround, try this on each shard "Edit Mode & Select All & Mesh > UV Unwrap > Project from view", tip from here


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How to keep the details and line thickness in freestyle despite the movement of the camera?
I'm trying to do a project with freestyle cartoon style.
I have two characters, one large and one small, both quite detailed. When I render separately I have no problem, but when I put the two together the small loses much of its details. Freestyle lines become too thick to the model and lose a lot of detail. The problem, I think, is bring in / out the camera to frame the two characters in the picture.
Is there any way around this?
Thanks
Example:

Does this help? http://blender.stackexchange.com/questions/3528/how-to-make-freestyle-lines-stay-the-same-size/3533#3533

See the link Ray Mairlot posted, but use Distance from Object instead of Distance from Camera. You'll need to make an Empty or something to serve as the object that will anchor the size.


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Blender Bones: How to Join Bones with Objects
My ultimate goal is to have a arm that can move in Unity. I have made an arm in blender and have added bones to that arm.
How do I connect the bones to the arm? Is there an easy shortcut to do this?
I am very new to blender, so any help would be much appreciated!

In Blender Select mesh. Then Select armature. Both are selected.
Control-P  will produce a dialog similar to the image below
Consider a blender tutorial video on some well known video site such as YT
In the past some (new to Blender) questions are cast away.


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Blender Wacom buttons not recognized - Linux Mint
I am having issue with Blender not catching Wacom buttons when pressed. Gimp and Houdini and every other app are working perfectly.
I set buttons using xsetwacom set command. Is there anything specific I need to do to enable this?
Thanks!


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Pin curve points for sofbody
I have curve, bezier, and applied softbody to it. Now question I have is, how can I pin one point on curve? I see Goal settings on softbody, and Vertex group option, but there is no vertex group for curve.

Found solution, setting weights on points does the trick.

Answer yourself and accept your answer.


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Blender Bevel Object scale issues corners
This is bothering me for some time in Blender. It would be excellent if this could work, especially for archviz. Anyone knows is there some workaround to fix this issue, when using bevel object on curve there are scaling issues on corners or ends (not sure where issue is)? Handle types are Vectors.
Attached image.

OK found solution myself, should just use 2D instead of 3D. It covers 80% cases so I can call it good.

You can increase resolution of the bevel object if you mean changing of the sharp corners. The more subdivided bevel object is, the more smooth beveled curve will be (and polycount will grow too)

Found solution myself, should just use 2D instead of 3D. It covers 80% cases so I can call it good.


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Why does my pose change when I try to change it
I am trying to change the pose of my charachter in pose mode. I am working on animations for a whole week and it worked every time. But suddenly when I try to change the pose in a certain frame, it sets itself back. For example: My charachter has a T-pose in frame 22, when I change the pose to a sitting pose in frame 22 and click on frame 23 and on 22 again, the pose I gave it is gone and the T-pose is back. Why does it do this all the sudden? I need help. If you need a video I can upload it. Thanks!

Without a .blend file, my guess would be you have autokey turned off when you had made the sitting pose on 22.  Because nothing got keyed, the previous keys' settings got re-evaluated when you scrubbed to frame 23 and then back to 22.

Okay thanks for the answer, I'll look into it later this evening and I'll let you know if it worked or not!

I have autokey turned onn and when I change the pose of my character I do see the keyframes in the action editor. Do you have any other ideas? If you wan't I could send you the blend file.

Sure post the .blend on pasteall.org/blend

I posted the blend on http://pasteall.org/blend/40908 the password is "Thanks". Thanks for helping me out!

I hope you can find the problem!

So I took a look at it and I managed to give it a T-Pose, so for now my problem is fixed. But the problem stil persists. You don't have to try to fix it anymore, if you wan't to and can then that would be fantastic but for now I fixed it. Thanks for the help Mike!


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Animating a material change along an axis of a mesh
Imagine a long cube, like a bar, that has a dark material, and you want to animate changing its material to a light material, but do it gradually from one end to the other, like filling up a tube, or like a progress bar that fills from one end to the other.
How can you do this in Blender?

Something like this ?

The principle is to mix your materials (the mix shader factor) upon a coordinate of your object.
Here I set the first key frame to -3 meters for X and the last one to 3 meters for X (I dont know why these values work, I had to try to find them...).
Edit : the blend file
Edit 2 : to make the transition sharper, add a "math/less than" node, as shown here

Thanks a lot @lemon Looks like exactly what I need. Can you elaborate on a few things. 1- the shader mixer does mix the full material (not just the colors) right? 2- what property are you animating? I mean what are the keyframes set on. 3- It may be that there is something very basic that I am missing but I just get a black cube in rendered mode (Cycles render engine selected).

Thanks again, in material view, it shows up fine, is there a way to control the smoothness of transition between the two materials? I mean it very gradually transitions from one material to the other Is there a way to make the border between the two sharper?

You're welcome @Ali. 1- Here I just used to simple diffuse shader but that may work with any shader (or other nodes behind them) 2- I am animating the location (X) values (they are in green in the mapping node). 3- I used a plane. For a cube you'll have to manage in which direction you want the effect. Or maybe UV unwrap it, set the UV appropriately and use UV instead of "generated" in the "texture coordinate" node. I will add the blend file in the answer.

I added a "sharper version" (the "less than" node is the last image)


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"No valid formats found" creating a video
I am using blender 2.76 on openSuse.
I have created individual frames in png format and I try to create a video from frames.
Any output different from "AVI jpeg" will show a "No valid formats found" error when clicking on "Animation" to create the video. I would like to compress the video somehow and "AVI jpeg" creates huge files.
For instance, I read in Blender Stack Exchange: As of Blender 2.76 you can correctly select Output as "H.264" and Encoding as Format: MPEG-4 and Codec: H.264. This generates the correct container and encoding AFAIK
For some reason in my case this will show "No valid formats found".
Any suggestion is welcome, thanks.

Related: http://blender.stackexchange.com/q/47166/2843

The comment of Samoth leads me to the solution. I downloaded 2.77 buildbot version of blender here: https://builder.blender.org/download/ And use it to build my video. It just works. Thanks a lot.


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Rendered viewport shading in blender 2.8 is low-res on Retina screens
Apologies for the long post (I feel I should offer a potato).
On Retina resolution screens Blender 2.8 is rendering low-res aliased images in the viewport where it should be rendering crisp high-res images as per 2.7x.
The images below illustrate the issue:
Soft aliased edges in 2.8:

While crisp sharp edges in 2.7:

And it has nothing to do with render / preview settings / samples as they are the same in both files and final renders are fine. I think it's a glitch in the 2.8 Beta version. Can someone report it? Or is there a setting I'm missing?
Thanks
JK

"it should be rendering crisp high-res images" That is what final rendering is for, previews should be quick and responsive

I use the viewport render to check the quality of what the final render will be, using border rendering etc. I don't need quick, i need accurate! Just want to set it back to how it worked in 2.7x.

This is a feature, which actually originated from using high resolution screens.
(Other users actually want to increase the pixel size.)
With highresolution screen viewing a small portion on your display, already requires lots of pixels to be rendered. If you just want to have a rough idea of the color and shapes, you don't need a highres version.

Go to the Properties Panel.
Go to the Scene Tab (the second from top).
Go to the Performance section.
Go to the Viewport subsection.

Change the Pixel Size attribute to 1x. If it is set to automatic, Blender probably realizes you are using a high resolution screen and adjust the preview pixel size for better performance.

Hi Leander, your suggestion about pixel size attribute successively halves the veiwport resolution. I'm trying to double it so it goes back to how it was in Blender 2.7x, smooth and sharp - not aliased. How do i report a bug? do you know? Thanks.

Creating with Guidelines.


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Environment mapping controls missing in Texture context tab - Blender 2.8
It seems Environment mapping controls are missing in the Texture context tab in Blender 2.8. Any reason for this?
Thanks
JK

Environment mapping is done in the World tab.

Yes, I have the map assigned in World tab. I'm talking about this:

https://imgur.com/a/UMIxt0q

The environment map can be set in the World tab or alternatively by using nodes in the Shader Editor.
To setup the environment map as depicted below, perform the following steps in the World tab on the default world configuration which only consists of a Background node connected to the World Output.

Click on the circular button for Color and select Environment Texture from the dropdown
Click on Vector and select Mapping
Click on the circular button behind Vector in Mapping and select Generated


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Rendering artifacts in orthogonal views
In 3D Viewport when I set the view to orthogonal the background grid goes all wonky. See images below. Obviously i'd prefer this not to happen, for the grid to render like a proper grid. Any guidance on this issue?
Thanks, JK.

I'm quite sure this is some sort of graphics driver issue, cannot reproduce that here. What GPU are you on?

CPU based on Mac. OS ver: 10.14 (18A391)

I suspect that is the culprit here - sorry I can't help with OSX :-/


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Input a SVG curve into a GN setup
I have a SVG curve from a client that I need to resample in a GN setup. I can't work out how to input it into the GN setup. Any way to do this?

Import SVG, switch Fill Mode to "None" in Object Data Properties > Shape, add Geometry Nodes modifier, do some cool stuff with the curve.

Great - thank you. I was looking for an actual 'curve input node'. I forget GN is a modifier concept.

If your question has been solved, please be so kind and mark the answer that contributed to the solution as "Accepted answer" so that this question will not continue to be displayed as unsolved. Thank you! Here you can find more information: What should I do if someone answers my question?. If you still haven't gotten a solution to your question, please be kind enough to address it.

The answer is in the comment above - I can't mark that as an answer.

No, this is just a comment, the answer is here below. The concept of this platform is that an answer is given to a question. If this answer is correct, it should be marked as "Accepted Answer". This is the only way to mark the post as solved and fulfill the idea of this platform. Thank you for your help!

Here's how you can do that:

Import your SVG file via File > Import (the add-on "Import-Export: Scalable Vector Graphics (SVG) 1.1 format" has to be activated)
In Object Data Properties > Shape switch the setting of Fill Mode to "None". This will not automatically fill the imported curve and convert it to a mesh.
Add the modifier Geometry Nodes and the node Resample Curve.


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Scale instances in Geo Nodes with noise texture over time
in the attached blend, there is a transition between a grid of instanced ico spheres and a grid of instanced cubes - modulated by a noise texture and controlled by a greater than / less than ratio that is, itself controlled by a keyframed changing value. The change boundary is binary, either one or the other. I'd like to 'soften' that change by adding a scaling down (size current to size 0) over 20 frames pre change (of the existing cubes) and then a scaling up (size 0 to size current) over 20 frames post change (of the 'new' ico spheres cubes). I cant work out how to combine the transition data with the noise texture information and then apply that result to the ico sphere and cube instances so that they match up with the transition. Any ideas? Thanks JK.

you can use map range and scale instances to do that:

result:

Explanation:
Ok, i assume that you did understand your blend file - so i only explain my change:
You had already the less than/greater than nodes, to instantiate a icosphere or a cube.
All i did was making a range from a discrete value.
I achieved this by using a map range node.
So i took your discrete value (the keyframed) and put this in one map range value. Then i added/subtracted a value (my new value node) to the from value so i could "stretch" the discrete value to a range in that the mapping from 1 to 0 (scaling of instances) can happen.

Wow that's amazing! I'm a total novice with GN - if you could talk me through a bit about what's happening here, I'd be grateful.

i tried to explain it - but you cannot be a total novice with GN if you came that far! ;)

Thank you - your explanation was very helpful. Tutorials really are what got me to this point. If you have tuts on YT or something, let me know.

i would recommend watching Johnny Matthews + Erindale, they make really good geometry nodes tutorials with great explanations


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How do you get a mesh to deform when you have it go along a path using follow path constraint?
The mesh object is highly divided so there are enough vertexes for it to deform (its not an 8 vertex cube) and I don't know armatures or have time to learn it. So I need a solution to deform the mesh as it goes along the path specified in the follow path constraint. thanks JK

I think you're looking for a curve modifier rather than a follow path constraint?  Constraints will never deform things; "deform" type modifiers, obviously, deformation is  their whole thing.

As @Nathan suggests, this sounds like a Curve modifier, with the modified object animated along its axis of deformation, rather than a Follow Path constraint:

There are plenty of answers here on the mysteries of aligning it.


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Text Reveal Effect using Geometry Nodes
how would I set up a Text Reveal as in the attached movie file using Blender Geometry nodes? I have no experience with geo nodes. It would be useful if the string of copy could be edited for different uses. Thanks

Your question is not really suitable for this site as it's really asking for a full tutorial. However you could probably modify this comprehensive tutorial about text effects using Geometry nodes and place your text behind a white plane so that it shows as it moves up behind it.

I would suggest either to learn GN, to use other features than GN, or to pay someone to do it.


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Is there a way to overwrite Blender's 16K limit for environment textures?
I'm rendering a planet in space. NASA has gorgeous equirectangular JPGs of the Milky Way up to 65K. I plugged in the 16K version and the render has blurry stars. To get them pin point I tried to load the 32K version. Render was cancelled with a note about the environment texture limit (16K) being exceeded. It there a way to overwrite this 16K limit? Thanks.

You will need close to a terabyte of memory for Blender to run and render that  size

The 32K texture is a 10Mb JPEG. How do you calculate 1Tb?

This is on your hard drive, in video memory image will be in raw data

It's not a exr or raw file, it's an 8-bit compressed JPEG. Could you elaborate? Or point me to a web resource where I can read up on this?

It doesn’t matter what size that texture file might have on your hard disk, as it will very likely be compressed one way or another. But the render engine needs access to uncompressed texture space. The memory consumption for that texture would be (if i'm not wrong) 8 bits* 4 Channels(RGBA) = 32 bits = 4 bytes ... a 32k is around 576 million pixels and so 4 bytes * 576,000,000 = 2,304,000,000 which is 2.04 petabyte.. Well, i was wrong is more than a terabyte.. If the calculation is wrong, please someone correct me

Sorry no: If an RGBA pixel is 32bits (4 bytes) then 4 bytes x 536 870 912 pixels (32768 x 16384px equirectangular environment texture) equals 2.14748365 gigabytes, not petabytes. A tough task for Blender to stuff that into 12Gb VRAM, but doable, I'd say.

Anyway, the question still stands: Is there a way to overwrite Blender's 16K limit for environment textures? And, if not, how can I get sharp stars in the background of my planet animation?

"If an RGBA pixel is 32bits"... RGBA pixel in Blender is 32bits PER channel. 4 channels - 32*4=128 bits per pixel... Anyway, memory is likely going to be a problem here. You can render only parts of the HDRI sphere with only parts of the texture you need. You can split the texture into a few parts and use it for a simple sphere split into matching parts and adjusted UVs with inverted normals and emission shader. You could probably use way lower resolution(like 4K) for reflections and lighting and the high resolution bits for background that is visible.

If I were you, I would just make my own star texture with a noise texture node. That would be more GPU-friendly. Something like this: https://i.sstatic.net/9ezn9.png


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Make a smooth tile texture with Voronoi texture run through a colour ramp node
I'm making a tile texture using voronoi texture run through a colour ramp node. The red colour part is not blending into the rest of the colour ramp. Any thoughts how to fix this?

Use a drawing software to draw how you want it to actually look, the solution depends on that.

Your Exponent value is way too high. Basically the Minkowski distance should be the Chebychev distance for the Exponent reaching $\infty$, but Blender seems to compute this not so well. Actually there is a blending of the red color into the white starting in the middle, however the red square increases in size with higher exponents and simply covers the gradient.
But what you might have already guessed here is since I mention it: what you rather want to use instead of Minkowski with a very high exponent is Chebychev to get the result you want:

You can get something similar with Minkowski and an Exponent of perhaps 16, but the corners are a bit round then. Everything above 16 makes the center square overlap the gradient.

Another way how you can get sharper corners with Minkowski is using the F2 festure instead of F1. Then you can even use an Exponent of 32. You only have to flip the colors on the Color Ramp and adjust the sliders to your liking.

Note that I have moved the sliders just arbitrary to get similar results, I did not try to make them all match as good as possible.
Also I do not know if you wanted the red to start from the center (because the red slider was fully to the left) or if there should be a visible red square in the middle. If so, then you can of course adjust the position of the red slider as well. With the setups shown above the gradient will then start at the border of the red square, not be just overlaying the gradient from the center. By the way, but if you use Minkowski with your high exponent, as soon as you move the red slider far enough so that the square gets larger, than you can see the gradient again from the square edge.

Thank you Gordon - appreciate those insights. The rub, however, is that I need those tight rounded corners that, AFAICT, are only offered by Minkowski with a high exponent. I suppose I'll need to rethink the approach. Thanks again.

@JKCapeTown Hmmmm... what about using two Voronoi textures: one with the black and white part, another with a red to white part. And then multiplying them together in a Mix Color node? Like this: Minkowski × Chebychev

Yes, that could work. Thanks again!


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How to create procedural gradient mosaic pattern
How can I combine a gradient and Voronoi (0 randomness) texture to create a gradient mosaic tile effect? Thanks.

Which kind of result do you want to achieve (as it is probably not the last image you have included)?

The last image is what I'm trying to achieve.

That can be this:

The value node indicate the scale (20 here).
1 over this scale is the value we want to snap the cells to. But the coordinates are before shifted half of it in order to adapt to the voronoi texture.
For the gradient: it is compared to a white noise texture in order to have a progressive color over the randomness.
Last, the voronoi screens the grid in order to have the white separations around the cells.

good ol' nodes magic is what i'm here for :))


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In Blender 3.5.0 how can you reverse the colour of the Voronoi Texture Distance output using math nodes?
In Blender 3.5.0 how can you reverse the colour of the Voronoi Texture Distance output using math nodes? The current output is black centre, white edges; I'd like white centre, black edges. Please don't suggest ColorRamp with swopped handles. Id like to do this with math nodes.

did u try just subtract? so math node (1 - distance)

you can try this node setup:

i am not totally sure whether 1 is the maximum of voronoi distance - you might have to play with that value - but that's how you can invert it.

Hi Chris, thanks great suggestion. But, yes, I'm also not sure what the range is that the distance socket outputs (0>1? Maybe -1>0>1?) I'm using the Moroni to drive displacement and when I input the pure Distance socket output into the height I get vastly different results to when I do the same using the ColorRamp on the noodle to swop colours, which I'm convinced is normalising the output.

@JKCapeTown The Distance output gives no values below 0 since the Euclidian distance can never be negative. It can be above 1 though, you can easily check this by using a Math node set to Greater Than with 1 as threshold. However, in the screenshot above you can see the new Voronoi Texture node which comes with version 4.0, there you can check the Normalize option which will map the values to the 0 to 1 range.

@GordonBrinkmann: didn't know that - learnt again something from you ;)

@Chris You're welcome. Additionally I must say that using Normalize although limiting the values also makes the result much less contrasted, the values don't seem to go down to 0. So I would rather use a Map Range node and try to adjust the Min/Max values so that they span over the complete range.

@JKCapeTown I forgot to mention: no, a Color Ramp is not normalizing the values. Normalizing is mapping the minimum and maximum values to a range of 0 to 1. The Color Ramp is cropping the input values to the 0 to 1 range. So if you plug in something that goes from -5 to 15, the Color Ramp crops it to 0 to 1, so -5 to 0 get the color which is at the left end, and 1 to 15 get the color at the right end.

Thank you Gordon. So what would you do to invert the Distance output of the Voronoi texture node to keep the 'integrity' of the numbers intact?

I'd like to have the full 'uncropped' range swapped around (a pure inversion), so I suppose your last instruction is how I should do that. Could you post a screengrab of how you would do it - just so I can be sure I'm implementing is right (sometimes I misinterpret written answers). Thanks v much.

@JKCapeTown I would use a Map Range node. However the problem is, the maximum distance is hard to determine because depending on the Voronoi pattern, the scale etc. it is hard to tell how much the maximum distance will be. It can even be that there is no value above 1. The question is: do you need them exactly from 0 to 1? Or do you just want to make sure they stay in this range without being cropped? Then you should use a Map Range with From Min = 0, From Max = Sqrt(2) and To Min = 1 and To Max = 0 (swapping min/max on output so there is no subtraction necessary).

@JKCapeTown There you go: vector normalizing, this is basically what the Normalize option in Blender 4.0 does. But I'm sorry, there was a mistake in my other comment, the From Max value has to be Sqrt(3), because the Voronoi Texture is set to 3D. If it was set to 2D it would have been Sqrt(2). You lose a lot of contrast there but you can be sure to not lose any values through cropping.

Thank you Gordon - it is appreciated.

Not an answer, just a (not so) short explanation/visualization in what range the Distance output of a Voronoi Texture set to Euclidian can result. The node generates random points (unless Random is set to 0) in 1, 2 or 3 dimensions which have a maximum distance of 1 per dimension (4D is like 3-dimensional with W working like a seed value).
1D: The output will be a single random value in $[0,1]$ (to get different values you can change W as seed).
2D: The output values are in $[0,\sqrt{2}]$ with each point lying in the plane, i.e. each "cell" has a black center with value 0.
3D: The output values are in $[0,\sqrt{3}]$, the point can lie above or below the plane, i.e. the center of "cells" can be brighter than black.
The reason for the maximum values of $\sqrt{2}$ for 2D and $\sqrt{3}$ for 3D comes from the formula for the Euclidian distance $d$ between two points $p$ and $q$ given through their coordinates $p=(p_1,...,p_n)$ and $q=(q_1,...,q_n)$:
$$d(p,q) = \sqrt{\sum_{i=1}^n (q_i-p_i)^2} = \sqrt{(q_1 - p_1)^2 + \cdots + (q_n - p_n)^2}.$$
For a 2D texture this means
$$d_{2D}(p,q) = \sqrt{(q_1 - p_1)^2 + (q_2 - p_2)^2}$$
and a 3D texture
$$d_{3D}(p,q) = \sqrt{(q_1 - p_1)^2 + (q_2 - p_2)^2 + (q_3 - p_3)^2}.$$
Since the node generates points with a maximum distance of 1 for each difference $|q_i-p_i|$, the maximum distance $max(d)$ two points $p$, $q$ in 2D or 3Dcan have from each other is
$$max(d_{2D}) = \sqrt{1 + 1} = \sqrt{2}$$
or
$$max(d_{3D}) = \sqrt{1 + 1 + 1} = \sqrt{3}.$$
To visualize that, here a simple illustration of these maximum distances two points can have in the 2D and 3D Voronoi Texture node:

Last quick note: regarding the minimum value of 0 and why there are no negative output values: physically nothing can be closer than distance 0, and mathematically each squared subtraction $(q_i-p_i)^2$ will always give a value $\geq 0$, therefore the square root of the sum is $\geq 0$ as well.


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Where is the sampling integrator in version 3.6?
Where is the sampling integrator in version 3.6? I can find it in older versions but it seems to have disappeared in 3.6. Thanks.

I believe it was removed as unnecessary when CyclesX was introduced in Blender 3.0. Can't find any docs to confirm that now though. It's certainly there in 2.93 but not in 3.3 LTS.

Here's a link to the 2.93 Sampling section of the Manual and here is the one for 3.0 with all later versions being the same.

This option has been removed since 3.0. In Blender 2.x under the Integrator option you can select between Path Tracing and Branched Path Tracing. Branched path tracing has been removed with 3.0, see here under section Removed Features and Compatibility

Branched path tracing was removed. We recommend using adaptive sampling to automatically allocate more samples where needed.

and an Integrator option with only one setting is pretty useless.
This is also in line with what @JohnEason pointed out, the manual for 2.93 explains the Integrator option while from 3.0 upwards the part has been removed (i double checked 3.0, no Integrator option anymore). Afaik they integrated CyclesX into 3.0 which had major changes under the hood. This blog section confirms the same:

Branched path tracing. We are working to improve sampling algorithms to make this obsolete, and more automatically assign samples where needed. Improved adaptive sampling and light importance sampling are key here.

These features will remain available and supported in 2.83 and 2.93 LTS releases.

If you mean CMJ, it was removed in Blender 3.0. Cf https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles


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Positioning multiple objects at once
I am exporting some of my meshes, how can I position them to the center of the world all withouht having to set the position one by one ? I know I can select all of them and position them by eye-balling it with the grab mode, but how can I position them all at once by entering the coordinates in the ''transform menu'' ?
Because for now, when i enter the coordinates, it only takes into consideration the last mesh that was selected in the group.

Snap cursor to center, select all, snap selected to cursor. Use offset to not change their positions relative to each other.

Ohhh I forgot about the shift+s menu. Thank you ! :)

Also press Alt while entering [0,0,0] value in the coordinates properties box, so it applies to all selected objects, instead of active one only

Not while entering. Alt + click into the coordinate properties box = set all selected objects. After entering Alt + Enter = move all selected objects according to active object.

Here are the steps I have followed
Selecting a destination (using existing origin point of that object)

Select base object

Press Shift + S and choose Cursor to Active

Got to FINAL STEPS

If you want to move an object to another object vertex in Blender

Select base object (destination)

Select Edit mode and choose the destination vertex

Press Shift + S Cursor to selected go to Object mode

Got to FINAL STEPS

FINAL STEPS
Now regardeless of what steps you follow above here are the steps to move other objects to the chosen destination above

Select the other object(s) (single or just shitf + click on each)

Press Shift + S and choose Selection to cursor (Keep offset)

Feel free to improve it since I'm very new to Blender

ALT+click doesn't work for me, SHIFT+click instead.

select all objects
define active with SHIFT+click on object
then SHIFT+click into location properties box
(release shift) enter desired value
and then press ALT+ENTER

All selected objects moved to specified location according to active object.


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Using a custom object to "hollow out" that same object?
I'm a total Blender noob here, so I apologize in advance if I seem to have trouble understanding.
I'm trying to create a "picnic basket". I created a simple trapezoid by extruding then resizing a plane. But the result is a solid box and I need to hollow it out.
I'm assuming there's a way to simply partially "insert" a copy of the trapezoid down into the top and use it to "hollow it out", but I'm not finding any info online.
Any help is appreciated.

Search for bool tool, it is an addon that does what you want very well.

You can also just select the top face, press i to inset and e to extrude down.

Delete the top face and assign a 'Solidify' modifier. Since your box is trapezoidal, an extrusion will produce an inside of a different shape from the outside, possibly even projecting through it.... but you could always scale the bottom inside face down...

Thanks for the replies.
WhatAMesh: I found a copy of "Bool Tool". Last version was 0.2 and is 4 years old. I installed it, but now where do I find it and how do I use it? (Like I said, I'm a noob.)
user2164882 & Robin: The top face is not a selectable material. My trapezoid is one solid object.

Follow up: Is the latest version of Blender (2.79b) incompatible with "BoolTool"? I installed & activated it, but no "BoolTool Tab" is added to my Tool Shelf (as described in another post.) :(

There is another easier, cleaner way.

create a Cube
resize the cube on X or y axis so it becomes a rectangular prism
go int edit mode and select the top face
press i to inset the face.
press i+z to extrude the new face downward.
select the bottom face of the cube as well as the bottom face of the hole.
press s to resize it to a "picnic basket".

What you need is a 'boolean modifier' which is already present in blender.

Select your trapezoid by right clicking on it.

Create a copy of this trapezoid by pressing Shift+D.
Move it upwards by pressing 'G' and 'Z'
Scale it down a big by pressing 'S' and align is as shown below.

Now all you need to do is remove the top object from the bottom object. You can do this by adding a boolean modifier on the bottom big trapezoid.You can do this by selecting the bottom trapezoid and going to modifiers tab, click 'Add modifier' and selecting the boolean modifier as shown below.

Change the operation to 'difference' by clicking on the drop down menu.

Click the eye dropper tool and then click on the top smaller trapezoid.

Click on apply button.

Now you have your basket. You can now delete the top trapezoid by selecting and clicking delete.You will get something like this.

Thanks! But it seems I screwed up somewhere. After I clicked Apply, all that is removed is the submerged portion of the smaller trapezoid. :(

Please save the file just before applying and share it here. I'll take a look.You can do this by uploading the blend file on this site - https://blend-exchange.giantcowfilms.com and copy + pasting the generated url here.

Okay, I figured it out. I still had the smaller trapezoid selected before I used the eyedropper. Selecting the bigger trapezoid first before selecting the object to extrude it with solved it. Thanks!

Good to know! Please close this thread by marking this answer as accepted.


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Turn "Modified" shape into primary Physical shape?
I'm working on a "Smart Watch" model. I used the "Shrinkwrap" modifier to create a rounded square for the shape of my watch case.
But when I import the shape into my game, It displays the original "unshrunk" box with sharp corners instead. The game's engine only recognizes original primary shapes, not the shape after modifiers have been applied.
Evidently, I need my "Shrinkwrapped" shape to be a "primary" (unmodified) object. Is there a way to do this?

(Please ignore outer texture transparency. That will be fixed.)

TIA

try to apply the modifier before exporting, but maybe you'd better model the object without the help of shrinkwrap, how does the real object look like?

What format do you export to in your game engine ? Some exporters have an option to "Apply all modifiers" on export

Thx for replies. THAT WAS IT "Georgious"! Model must be exported to a Collada dae file. And there was indeed an "Apply modifiers" option. Huge thanks!


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Can't move/resize texture in UV Mode
For some unknown reason, I can't manipulate my textures while in UV Edit mode (both v2.79 & 2.80.) The texture is applied and displayed on screen, and when I go into UV Edit mode, the UV Map appears over the texture like it should, but then any changes I make to the map have no effect on the applied texture. Resize, rotate, move, the map changes but the texture doesn't and I have no idea why.
I'm trying to edit an old Blender file (probably created using v2.64 but I don't think it matters.) I can't stand the new v2.80 interface (what used to be simple things are now 12-step processes) so I prefer to continue using 2.79.
I'm not a total Blender novice, but I'm definitely on the low end of the scale when it comes to knowing why things do what they do.
Any help is appreciated. TIA.

I'd say you'd really want to explore Blender 2.8, I kept on using Blender 2.7 but then I realized, I am missing so much and now after I moved to Blender 2.8 I never want to think about 2.79 :D
Also could you share your blender file to check if that's okay?

I'd suggest sharing some screenshots of the problem you are having so we can see what might be a solution then - description only goes so far.

Thanks for the reply(s). I've uploaded a screenshot here. Changes to the UV map produce no change to the applied texture on the right.

Can you share your blend file, screenshots aren't looking enough!

I temporarily uploaded the file here. Thanks.


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HALF of the image is flipped on a curved plane?
I'm a bit of a Blender novice, so be gentle.
I'm trying to create a simple movie screen using a curved plane. I created a 2D plane, applied a simple 90' curve, and UVMapped a single png for the texture.
When I first applied the UVMap, I noticed my texture started displaying from the center of my plane outwards to the right and was both backwards & upside-down. Rotating the UVMap 180' moved the left side of my image to the left side of my object and displaying properly, but now the right HALF is rotated 180' starting from the center of my plane.
WTH? How do I fix this? How do I rotate only half of my texture? (editing the png is not an option since the texture will change.) TIA

(Download the Blender file here.)

Press 5 on Numpad and Press Ctrl+1 (User ortho and turn to back ortho) The Image will spread.

In Edit Mode Press U and select Project from view
Drag and make a new window as UV Image Editor
Scale UV on X and Y axis untill it match the mesh.

Great! That worked. Now WTH did I just do? :D

@atek Wow, those .gifs are a great way to answer someone's question. Nicely done.


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Laser scanner shadowing
I've been searching for a few days now to no avail, no doubt it's my searching skills which are lacking. But I'm trying to represent how an industrial laser scanner sees the world (especially how the laser scanner creates its own shadows with the objects it interacts with).
Where the field of view of the scanner emmits a red field looking forward, and if something blocks the light emmited the field doesn't continue creating a "shadow" on that red field.
See the image for an example, notice how the tines of the forklift create a shadow on the laser scanners field of view.

Any help is greatly appreciated
Thanks
Evan

if it is as the image then you are looking for Volumetric lighting

Yeah that makes sense, and i have been able to get volumetric lighting for an entire scene, but i am completely stumped in how to make the volumetric lighting only affect one thin plane.

and alternatively to make the field of view look less "foggy" like seen here
https://i.ytimg.com/vi/pOAPFS9GwAE/maxresdefault.jpg
ideally im trying to create a material to get the shdowing effect and i could tweak the look of it (colour, transparency, glossy surface etc)

Sadly you cannot isolate the effects of a lamp on an object in Cycles as you can using Blender Internal Renderer layers.
So I tried building an intense isolated lamp & enclosure. From this I include a volume box for the emitted light to excite. The enclosure cam be hidden from the camera by simply turning off its Object Properties > Cycles Settings > Ray Visibility > Camera.

The material for the volume uses a scatter with a density of 0.03
While the Spot lamp in the box with a slit has a high emit/strength value of 50,000. You can have a wide spread or a narrow beam by altering the Spot angle.
To reduce render time you could build the volume box to exactly match the beam spread of the laser.

I think that an OSL could achieve this effect as a material boolean or cut away from intersections from some defined emission point. But it would only render on CPU. And the script that I'm thinking of isn't released yet :-(


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get radius of mesh primitive
I would like to ask whether there is a way of getting the radius of a sphere (mesh primitive) after it has been added. In other words, does Blender somehow distinguish between different shapes?
What I would like to do, is writing a python script to find all spheres in a scene and execute an action on them only. Then find all cylinders and execute another action on them. Is this sort of shape detection possible in Blender or do I have to specify a variable for each object by hand to make the distinction?
Thank you very much in advance!

Once a primitive has been added and you are past the settings stage Blender only thinks of it as a mesh, no distinction is made as to if it still is a primitive, or what type of primitive it started as.

If you have control over the creation of such objects via Python, then you could add metadata to each created object (the metadata persists within the .blend file) and do your tests based on that. You could have ob['primitive_type'] = 'sphere' at creation time and then later test for ob in bpy.data.objects: if ob['primitive_type'] == 'sphere': do_action()

Of course if the annotated sphere mesh is edited in vertex mode and transformed into a tube-like thing (that must be cumbersome) then your annotation isn't valid anymore but the probability this happens is quite low :)


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how to get the area of a polygon in python API?
I would need to get and compare the area of the polygons/faces of objects of different shape. I found the variable 'area' in class bpy.types.MeshPolygon but this does not give me the real area of the polygon after scaling and modifying a mesh primitive. Why is this? Is there another way to get the area?
Thank you for your time!

Did you scale the mesh geometry in edit mode, or is the object datablock scaled?  Perhaps if you use Ctrl-a to apply the scale it will adjust the mesh so that the area is what you want.

Thank you for the quick answer! I had indeed overlooked applying the scaling!

The short answer is with my_face.calc_area(), but anyone trying to calculate polygon area should check out this answer, because quads may return incorrect area values unless first triangulated.

Since matrix cannot be passed in API BMFace.calc_area().
There is a function like BMFace.calc_area()
from mathutils import Vector

def get_area(list_of_vec):
    n = Vector()
    v_prev = list_of_vec[-1]
    for v_curr in list_of_vec:
        n[0] += (v_prev[1] - v_curr[1]) * (v_prev[2] + v_curr[2])
        n[1] += (v_prev[2] - v_curr[2]) * (v_prev[0] + v_curr[0])
        n[2] += (v_prev[0] - v_curr[0]) * (v_prev[1] + v_curr[1])
        v_prev = v_curr
    return n.length * 0.5

Example:
import bpy, bmesh

ob = bpy.context.object
bm = bmesh.from_edit_mesh(ob.data)
mat = ob.matrix_world
face = next(face for face in bm.faces if face.select) # assume selected one face in edit mode

print(get_area([mat @ loop.vert.co for loop in face.loops]))

But what about non-planar n-gons? What is an area of non-planar n-gon anyway?..

I mean: which one is it for the first face?

I assume there are many polygons in an object. So add their areas separately for every face to get the result. For non-planar n-gons, the results should be similar to the API: BMFace.calc_area()

Calculate BMFace area with a matrix
# select a face..

import bpy, bmesh

def get_bm_area(bmface, matrix):
    bmtemp = bmesh.new()
    verts = bmtemp.verts

    for loop in bmface.loops:
        verts.new(matrix @ loop.vert.co)

    face = bmtemp.faces.new(verts)
    face_area = face.calc_area()
    bmtemp.free()
    return face_area

ob = bpy.context.object
me = ob.data
bm = bmesh.from_edit_mesh(me)

face = next(face for face in bm.faces if face.select)

print(get_bm_area(face, ob.matrix_world))


text:
assign color polygon python API
how can I assign colours to a specific face/polygon in the python API? I have found a way of creating materials, but how can I use them through the API on chosen polygons of an object? Does an object have to be fully covered with a material before you can change that of individual parts?
Thank you for your time!

Possible duplicate of http://blender.stackexchange.com/questions/18544/edit-an-objects-material-in-blender-using-python/18581#18581

The mesh doesn't have to be fully covered with a material, but it does have to have material slots(at least two) if you want to be able to change individual parts.
import bpy

obj = bpy.data.objects['Cube']
mat = bpy.data.materials['Red']
mat_slots = obj.material_slots
polys = obj.data.polygons

#add a material slot using a material
obj.data.materials.append(mat)

#remove material from material slot
mat_slots[0].material = None

#add the material slot that will be used for individual face
obj.data.materials.append(mat)

#apply material to one face
polys[0].material_index = 1


text:
comparing z axis of normals
I would like to sort objects faces with the Python API based on their normals, and more specifically, the orientation of the Z axis of the normals.
What would be the easiest way to do so? Comparing the normals directly does not work because I want to overlook the rotation about the z axis (that is to say, I am only interested in whether the face normal has its z axis parallel or perpendicular to the z axis of the world frame).
Thank you for helping

do you want the math or do you need how to access normals?

http://blender.stackexchange.com/questions/43985/how-can-i-compare-normals-in-an-with-python   (it is Not really specific to Animation Nodes) the script does exactly what you do (compare to world xyz) and my answer shows exactly how to compare normals due to the float imprecision issues.

Note that:  1. the normals are just vectors, there is no rotation around normal axis,  2. sorting is one, filtering some is different.  3. Are those faces in an object? Or generated by the script? Is the object moved/rotated or we calc only as default ..

Here's an example that shows you what normal is parallel or perpendicular.
(I'm not sorting the list, cause you say sorting, but then only care for parallel/ perp. ?)

check the object type and if has faces
list normals, including obj world rotation + scale
compare with vector.dot so that 1/-1 are parallel, 0 is perpendicular

Note the > < 0.0001 comparison rather than == cause of the float precision issues.
from mathutils import Vector

orientZ = []

if Object is not None and getattr(Object, 'type', '') == 'MESH':
    if Object.data.polygons:
        worldZ = Vector([0, 0, 1])

        mat = Object.matrix_world
        loc = mat.to_translation()
        normals = [(mat * p.normal - loc).normalized() for p in Object.data.polygons]

        # if dot is 0, is perpendicular, 1/-1 are up, down
        for n in normals:
            dotN = n.dot(worldZ)

            if   abs(dotN) > 0.9999: orientZ.append(1)
            elif abs(dotN) < 0.0001: orientZ.append(0)
            else:
                orientZ.append(-1)

and gives a list of 1, 0, -1 for Z, perp, others

Another example is this
How can I compare normals in AN with python, doing the same, by distance compare to world XYZ axes.

Thank you for your answer! And yes, using the word "sort" was actually incorrect, sorry for the confusion!


text:
triangulate mesh in python
Is there a simple way of triangulating all faces in a mesh in the python API? I am already aware of that you can do it in blender by selecting an object in edit mode and pressing ctrl+T, but I need to do so in a python script.
Thank you in advance!

You could use the bmesh.ops.triangulate
See TextEditor > Templates > Python > Bmesh simple edit mode for some of the boilerplate.
For any mesh in object mode.
# This example assumes we have a mesh in object mode.

import bpy
import bmesh

def triangulate_object(obj):
    me = obj.data
    # Get a BMesh representation
    bm = bmesh.new()
    bm.from_mesh(me)

    bmesh.ops.triangulate(bm, faces=bm.faces[:])
    # V2.79 : bmesh.ops.triangulate(bm, faces=bm.faces[:], quad_method=0, ngon_method=0)

    # Finish up, write the bmesh back to the mesh
    bm.to_mesh(me)
    bm.free()

# Get the active object (could be any mesh object)
triangulate_object(bpy.context.active_object)

For any mesh in edit mode.
# This example assumes we have a mesh object in edit-mode

import bpy
import bmesh

def triangulate_edit_object(obj):
    me = obj.data
    # Get a BMesh representation
    bm = bmesh.from_edit_mesh(me)

    bmesh.ops.triangulate(bm, faces=bm.faces[:])
    # V2.79 : bmesh.ops.triangulate(bm, faces=bm.faces[:], quad_method=0, ngon_method=0)

    # Show the updates in the viewport
    # and recalculate n-gon tessellation.
    bmesh.update_edit_mesh(me, True)

# Get the edit mesh
triangulate_edit_object(bpy.context.edit_object)

Thank you for the answer, this is what worked for me in the end.

In Blender 2.81 I used bmesh.ops.triangulate(bm, faces=bm.faces[:], quad_method='BEAUTY', ngon_method='BEAUTY') to make above work.

It turns out that the script mentioned by WDC is exactly the one that we would see if we went to the Faces Menu (Ctrl + F) and actually floated our cursor over the Faces to Tris option until the tool tip appears. One can very often find the python script which triggers from using the UI by consulting the menus in this way. If you don't see the python scripts listed in the tooltips for menu items, then you may need to enable this feature in User Preferences under Interface > Python Tooltips. Saves a lot of guess work and downtime to be able to refer to these.

@R-800 Please note the difference between bmesh.ops as mentioned by WDC and bpy.ops as seen mousing over UI.

without bmesh, you can do: ob = context.object ; mesh = ob.data ; loop = mesh.loop_triangles ; tri = loop[0] ;


text:
Why Can't i get back to the normal screen layout?
My screen layout in one blend won't go back to normal. Even if I go to the tile area there is no bar for the different screen areas like uv editing. in the right hand corner where file and window is supposed to be, there is the object mode, rotate,scale and transform option. Look at the picture[look at the arrow

Related - http://blender.stackexchange.com/questions/8384/how-can-i-reset-my-menus or this - http://blender.stackexchange.com/questions/822/how-do-you-return-to-the-default-view-the-one-you-see-when-blender-starts

By the looks of it I'd say you have several (5, to be exact) 3d-View Windows. Selct one of the cube icons, I would suggest the second counting from left to right and set it from 3d view to "Info". Then you can change between the presets.


text:
How do i add weights to bones that i added after i parented the armature to the mesh?
So i added two bones to the armature after I parented the armature without those two bones to the mesh. I named them mouth lower and mouth upper, but when I select the mesh they are not in the vertex groups. How do I fix this?

Related: https://youtu.be/eF4CuIX40XE

Find out the names of the newly-added bones
It's listed in your Properties Panel, under Item.

Create Vertex Groups on your Mesh with those names
Bones look for vertex groups with corresponding names to deform.

Paint on some weight

You can do this from Weight Paint Mode, or alternatively use the Weight slider to specify a weight before clicking Assign. Always pay attention to which vertex group you have selected when weight painting.

Thank you! Was following a tutorial and they missed this important part. Since I was rigging a different gun than the one in the tutorial I could not understand why all my parts didn't move with the parent bone. This solved my issue! :)

@ChristopherSmit I'm glad you found it helpful! It's nice to see an answer I posted ages ago still having relevance for people. :-)

definitely! I'm so new to blender and come from a programming background, so still have a lot to learn. If you don't mind, maybe you can have a look at an issue I am having now? I posted a question here - https://blender.stackexchange.com/q/271404

authors: محمدحسین میرزائی


text:
Why does the mesh get deleted when parenting to the generated rigify rig?
I adjusted the bones in the rigify add on and they fit my mesh, then I generated it and it still matched up well, and when I parented it with automatic weights, it goes from a full human to what's shown in the image.

Hi Nolan, can you post a .blend?

Did you apply scale to your model before parenting to the rig? (Ctrl + A)

@MikeBelanger I didn't parent the rigify to the mesh yet. The original bones are in the second layer. Check it out: https://drive.google.com/file/d/0ByrMQl4A3FTwRUxmVTRsbm1xZTg/view?usp=sharing

You called it Timaroberts.  The scale of metarig (I'm assuming that's the master rig) was bigger than metarig.001, which I assume is the slave rig.  So all I did was scale metarig.001/apply metarig.001 to metarig's, applied the scale to both armatures/mesh, and then changed your mesh's armature settings to point to metarig.001.  http://www.pasteall.org/blend/40846


text:
Can fire be made stationary?
I am attempting to render an animation where the camera rotates around an object that is engulfed in flames. My goal is to have the camera rotate but for the flames to be immobile throughout.
Is this possible? I have seen tutorials where the flames are made to slow down, but none where they are motionless.

As long as you don't need the smoke to start animating again after it has stopped you can set the start and end frame for the bake to before the set animation frames start.

Above I have set the start frame to -50 and the end frame to 1.  Once baked, the smoke animation will be done by (and freeze) at frame 1 and stay frozen for the full animation.  (For some reason the end frame can not be set lower than 1, but the start frame has no such limit.)

Thank you, this works much better than the workaround I came up with after posting.

@PGmath You got there before I did (great answer, as I was going to even give the same exact values). I'm going to modify your answer to include the rendered proof of this setting.

@RickRiggs  Great, thanks.  (I'm on my tablet which isn't a fan of simulations.)


text:
Multiple Object Tracking
I am doing a juggling project and need to track the motion of 3 balls (red, yellow, and white). So far, I've been really liking Blender's UI for motion tracking. I have manually tracked an individual ball for 1800 frames and am wondering if there is a better way of going about this. The balls are regularly occluded and sometimes go out of the camera's view, so is there a way of tracking each ball using one track per ball for the entire duration of the video? I also would like to export the curves from the tracking to a graph so that I can present my data. What are some methods I can use?


text:
How many vertices can I connect to a face?
I was wondering how many vertices I can connect to a face. I mean, when modeling, I can connect as many as I want, but is it allowed to do such stuff?

Because I know that if I raise a single point on one of the edges on the example below, the face will have a strange form.

If you look at that from different angles, you can clearly see that there are edges but that aren't selectable (I don't know how to explain that). You can see them but there's not an outline of them.
So my question is, if I don't have the intention to move the surrounding edges of that big face, can I leave it like that (image  1)? Or do I have to triangulate it or what?
Ps: Maybe for a basic scene it doesn't matter. But I do it for a game that's why I'm wondering if I'm doing anything wrong.
Thanks

Read https://blender.stackexchange.com/questions/89/when-should-n-gons-be-used-and-when-shouldnt-they/95#95

If it's a big flat surface, it is absolutely fine to leave it as Ngons. A polygons with more than 4 vertices are called N-gons. For rendering and UV unwrapping there should not be much issue, if it's going to be staying within the blender environment.
However if you are working on models that would be exported into a game engine, it's best to define your 4 sided polys all over your meshes as much as possible. Games engine tends to mess up your triangles when no definition of edges are found. They pretty much auto tesselate your meshes for you, which usually produce "unhappy" results producing in-game artifacts.
The link that iKris posted is pretty clear on a number of reason when to use them, and when to avoid them.


text:
Adding 2d sprite in 3d environment
I would like to add 2d images (like grass, leaves), but where i want. Tutorials on youtube doesn't show that (or i can't find the one i want). I would like to choose where i want a particular image and fix it to my 3d model.
For example in my case i have a wooden bridge and i would like to make some grass hanging from it but i want it to be 2d sprites cause i don't need to have that in 3d.
How can i achieve this?
Thank you.

@MrZak Lol, not related at all bro

Of course it won't be, you should give enough information if you want to get a help.

@MrZak Bruh, i got help, you downvoted cause you can't understand a question. Someone else helped me without being as arrogant as you...

Why do you think it was me downvoting ? I'm not the only one on site having this possibility. I would be careful with such words like "arrogant" without any real reason. The point is that your question isn't clear enough. If you got help then accept the given answer to show that it's useful.

In your “User Preferences” enable the “Import Images as Planes” add on.
Press Shift + A select "Mesh" then select Images as planes from the drop down menu. Import your image/Sprite (Check “Use Alpha” if applicable).
In “Edit Mode” select a vertex where you want to add your sprite/grass > Shift + S select “Cursor to selected. > In “Object Mode” select the plane/image you imported by clicking on it > Shift + S select “Selection to Cursor.
Nodes for alpha channel:

So i tried that and how do i make the plane invisible? also i imported a png so it's all black everywhere around the image.

Updated my answer to address this.


text:
Volume Scatter goes Black
I've followed some tutorials on Volume Scatter material in Cycle like this one :
http://www.blenderguru.com/tutorials/make-atmospheric-lighting-blender/
But I can't go any further because of this :

This is the render of a Volume Scatter material applied on a simple cube.
Whatever the object, whatever the shape. If I turn on the volume on the complete scene, everything goes black.
CPU or GPU render, it's the same. I tried every single option in the render & material, it does not change anything... I'm out of option.
I was really fancy to use that awesome feature, if someone has a solution, I will be super happy !
Thanks !
Happy blending !

Related - http://blender.stackexchange.com/questions/7231/cycles-node-setup-for-volumetric-shader. See also this and wiki for even more info. In general, volume shader should be connected to the Volume input socket of the Material output node. For now it's connected to the Diffuse which is why you get it black.

Your cube is black because your volume scatter node is plugged into the surface input of the material output node.
From the manual page on the shader,

The Volume Shader output must be plugged into the Volume Input of the Material or World Output node.

@ Timaroberts - This may be offtopic, how do you make those gif on your answer, is it blender's screencast or some other software?

@hawkenfox read here on how to create them. http://meta.blender.stackexchange.com/questions/963/what-is-the-process-for-creating-gifs-for-questions-and-answers

Thanks ! I didn't check the nodes,
I'm fealing bad it was so dumb |-(


text:
Stitch video with blender to make a 360 video
I'm looking to use blender to stitch together multiple videos in order to create a 360 video. How would I go about doing this in blender? Just to be clear I'm not looking to render a 3D scene in 360 but rather take multiple videos taken from different angles and stitch them into a single 360 video.

You could project each camera onto the inside of a sphere, use masks on the video textures to hide overlapping edges. But you wont get quite the right distortion.

@3pointedit that's actually an interesting idea. I'm not sure how well that'd work but it's interesting.

This is not possible.
Here is a google search for possible free alternatives, I cannot, however recommend any of them: free 360 video stitching software

Yea...my biggest problem is I haven't found anything that runs on Linux.

Dual boot with windows, or try using wine. Maybe you could try using Hugin to do the alignment, and then custom code to project and stitch the video.

:/...I've been avoiding that but it's not looking like I have a choice.

In fact, if you have the yaw pitch roll information (which can be gathered from one still image, using Hugin or PT Gui), blender could do the distortion and blending.

Yea I actually installed hugin but I haven't played around with it much.


text:
Rotate only an extrusion
On this site:
http://blenderartists.org/forum/showthread.php?283909-ramp-modeling
Poster Kaluura gave an excellent demo of ramp building.  I've done a lot of complex shapes but I couldn't get the ramp to work and make the edges meet other objects in my scene properly.  This demo looks like it will do the trick and I understand most of the steps.  I'm actually stuck near the beginning however, because in step 2, he has a nice graphic and says "Extrude without moving. Rotate the extruded loopcut on the Z axis around the 3D cursor."
I can't seem to rotate the extruded face while leaving the original face in place.  Can someone more experienced and wiser translate this step for me?   Thanks.

Extrude (E), then cancel (RMB) then rotate (R).

You notice his cursor is offset to the left so when he rotates the face, it rotates around the cursor position instead of in-place.  To get that effect you need to make sure you are using 3D Cursor as your pivot point before rotating the face.  The button for pivot point is at the bottom of the 3D view next to the viewport shading button.

Another way (which I prefer) is to select the front faces of the ramp, go into top view then hold CTRL and left click in the view away from it, this will extrude those faces and rotate at the same time.  All you have to do then is CTRL+Left Click around the view and your track will be built much quicker.

Yeah, the 3D cursor is in the proper place.  I've set it up some distance away (1m) so that I can rotate the ramp around it as I build it.  The point is, when I press 'E' and escape, I can't then seem to rotate only the extruded edge.
And if possible, I'd like to do so with a dialogue box so I can specify the angle to rotate by.

OK, I found the problem.  I had changed the origin.  I usually change the origin of new objects to something I think is useful.  Somehow, the pivot center was not set to the origin though.  Instead it was set to the bounding box.  That's what kept throwing off my transformations.   Your answer pointed me in the right direction even though I had actually set the pivot point.   For future readers there is a button on the bottom called "Pivot Center for Rotation/Scaling.  You have to make sure this points to your objects origin.


text:
How to make ray traces visible? Can I use blender for experiments with reflectors?
I need to make something like that:

Not cycles, at least without modifying the source code

Just a wild guess. Instead of using "light". Couldn't this be simulated with particles instead?

@xuv, it's crutches.

authors: Василий Киселев


text:
Snap to grid lines when moving verticle acros the path
I need create new verticle on path in point where grid and path are crossing.

How I make it:
1. Select points
2. RMB and subdivide
3. Select new verticle
4. Shift + V to move across path
5. Trying to move it with CTRL SHIFT and ALT modifiers
Sometimes it works

Sometimes not

How it works in inkscape

Maybe trere is easiest method?

ok this might be a funny solution but it works!

your line
make a line with e to desired location and connect to other with f
do the same to other side
join two new verts with J
clean the verts with ctrl + x

Emmm... It's terrible :) There is no simple solutions or plugins for just snap to grid?..


text:
Changing Grease Pencil stroke placement? (2.8 Beta)
So, I'm trying to re-draw something I made in the annotation tool (while projecting to the 3D cursor) with the new grease pencil tool (in a grease pencil object, of course), but it doesn't seem to project the same way.
When I was drawing with annotations, there was no problem. I could change it to project to the cursor and sketch (doing this so later I can use the camera for perspective, I'm experimenting with it).

and here's what happens in motion (I couldn't figure out how to embed it...)
https://i.sstatic.net/SGVTH.jpg
Basically what I'm trying to do is find the options listed here. I need to change the projection to cursor so I can draw on the same "layer" as it is how I would describe it.

You could try to move the Stroke OBJECT (in object mode) to the place where you're drawing, using it like the 3D cursor. Then, it will work like the cursor was before.
Hope that helps-


text:
Initial state for particles
Is it possible to setup initial state for particles? I want to simulate drops on bottle, and need to be animated. If this is simple animation I would probably just render from specific frame but I need it to be from frame 1. I can not start emitting from negative frame as than particles are not colliding with collider, they only start on frame 1. But on frame 1 I need all particles to be born and none born after that ...

What exactly is the problem? Can't you just set the emission to start at frame 1 and then stop at frame 1?

You can set the start and end frames of the particles emission in particles setting tab. This can be negative frames (end must be the same or greater than start).

As I said, than particles do not collide with collider. Collider starts to affect particles starting frame 1.

I found if I put Start and End Frame to 1 it almost gives me what I need, so I can work with this.


text:
How do I import a dxf?
I am a noob with blender. Please be as specific as possible. College students have been doing this for me, but I am unable to understand them.

related: http://blender.stackexchange.com/questions/26953/how-can-i-uninstall-an-add-on (specifically if your have additional dxf importers enabled... which might happen...)

There are various dxf import / export plugins, but they are not enabled by default. One of these is specifically for Import (read carefully).
In the User Preferences window find the Add-ons tab.

Then when it's ticked, the .dxf import option becomes available in the File->Import menu


text:
Render separate "back part" and "front part" so I can place something in between in other program?
Imagine a spinning rings like the animation in this page http://en.wikipedia.org/wiki/Gimbal_lock
If I planned to have my 2D character floating at the center and apply some crazy effects with After Effects, since that program is not a 3D program, I must render the scene as a sequence of images to further process it in After Effects.
To place something in-between I think I should have 2 set of images which is in the front and back of specified Z value. My character will be at that Z so when some part of the ring spin over it will occlude the character correctly. Is there any way to separate rendering into 2 parts like this? (Or any better way?)

A common technique in 3D is to render a Z-Depth pass. With this Z depth used as a mask in your favorite compositing app you can place any object at any depth (you threshold the mask to desired value with levels).
The advantage of this is that you have the freedom to change the Z-position of your 2D objects in postproduction. Exporting a Z-Depth pass is also often faster than rendering multiple times.
You can create Z-Depth pass with custom material, mist pass or remapping the Z pass values:
How can I get a Depth of field render pass?
Compositing fog destroys PNG alpha in Images as Planes when using Cycles
Here is how to use such pass in After Effects:
Video Copilot Explosive training (At 35 mins)
He mixes 3D debris and objects with 2D explosions through Z-depth mask.

You could render the object animation twice, once with the camera clipping the far geometry, and a second time clipping the near geometry. Side on that looks something like this:
far clipping:

near clipping: (shown in wireframe to allow you to see the Display limits property of the camera)

Blender can map the images from that other piece of software on a plane.  Consider the object in the middle as a plane with your ... transparent/alpha file.png sequence as a texture.
Since this is a Blender site I may be promoting Blender in the extreme.  Perhaps all the work can be done in Blender.
The 3d View Render has pixel compositing to blend image sequences layer by layer with many (after) effects.  The video sequence editor has features for more simple composition.
It is always interesting to know what some other program can do that Blender can not.


text:
flip uv map without numpad
I try to flip a uv map in uv editor mode. I read that S, X, -1 should do the trick but I don't have a numpad and it doesn't work even with the emulate numpad option switched on.
Any idea?

Select the UV island/islands you want to flip, press Shift+S-->Cursor to Selected. Change the Pivot type to Bounding Box Center. Then go to UVs-->Mirror-->X axis.

Also you could press Ctrl+M for mirroring to make operation a bit faster.


text:
Using Knife_project in command line
I have developped an addon and I want to call a few function from command line.
Everything works fine except when I'm using knife_project.
Here is my code:
bpy.ops.object.mode_set(mode='EDIT')
region, rv3d, v3d, area = view3d_find(True)
# Define context override dictionary for overriding the knife_project operator's context
override = {
    'scene'            : bpy.context.scene,
    'region'           : region,
    'area'             : area,
    'space'            : v3d,
    'active_object'    : bpy.context.object,
    'window'           : bpy.context.window,
    'screen'           : bpy.context.screen,
    'selected_objects' : bpy.context.selected_objects,
    'edit_object'      : bpy.context.object
}

# Set view to TOP by directly rotating the 3D view region's view_rotation
rv3d.view_rotation = Euler( (0,0,0) ).to_quaternion()
# Force redraw the scene - this is considered unsavory but is necessary here
bpy.ops.wm.redraw_timer(type='DRAW_WIN_SWAP', iterations=1)
bpy.ops.mesh.knife_project(override, cut_through=True)

Thing is, I don't have any error in the output log but my mesh is not cut. My guess it's due to:
bpy.ops.wm.redraw_timer(type='DRAW_WIN_SWAP', iterations=1)
Do you know if it's possible to use Knife_project in command line ? Or do I have to redo this part of the code to use another function ? (Is there an other function to cut in Blender ?)
Thanks for the help

Hi. You mention the 'command-line' but you're just using a Python script. Is the script going to be called from the command line?

Hi, yes the script will be called in command line via: blender -b -P /my/script.py


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Wiil a speedtree cast shadow in cycles render?
I want to know how can I cast a shadow of a tree to my render.
If I use a speed tree in front of the light, will it cast shadow to the objects?
Or should I place a 3D tree model?
Or else should I place a plane with tree texture?\
Which one would be better?

I'm not sure I understand.. What's a "speed tree"?

So I gather that SpeedTree is software for modeling plants... that's about all I know from 10 seconds of searching online. But if that software generates textures and UV maps it's just a matter of setting up those textures correctly with Cycles nodes. I'm inclined to think it should work. Why don't you give it a try? Sounds like you have a pretty specific workflow, so the best thing to do would be to test it out.

Also, as a general tip when dealing with lots of foliage: make sure your max transparency bounces are turned up high enough or you may encounter problems like this.

It will likely cast shadows. If you came up with an answer, please post it so that future visitors can get help from it.


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How to avoid smooth and roundnes in my alpha brush when sculpting hard surface?
Im totally a noob in sculpting with Blender, I want to use some alpha brushes to sculpt hard surfaces, I add a texture as a brush, select the texture under the sculpting brush, but when I use it it´s rounded and soften towards the corners (see picture).
This happen to me with every texture I try.

How can I make my brush harder and avoid this softnes?
Thank in advance to anyone who can help me out with this.

I solved it, it was an oversight on my behalf, i just selected the straight "set brush shape" option in the "curve" tab


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Triangles forming in a mesh with no triangles when rendering
it appears in both in cycles and blender render, there´s no difference between the preview and final render, whats causing it?, i don´t have triangles in my geometry

It's possible also that the faces are non-planar. To check it select all, and choose Mesh > Clean-Up > Split Non-planar faces. If something changes with mesh then that's (one of) reasons. Most likely you will need to retopologize mesh.

in a simple plain, when you move a vertex in a way that it can't be in a same height with other edges, blender creates an edge between edges to keep your shape as it is.
Take a look at this:

There is couple of ways to fix it, First you can add a little bit bevel to the mesh and then a subdivision to give blender more edges to play with(easier to do but heavier mesh).
Or you can add triangulate modifier and do some "edge rotate" on edges that you want to be in other direction. (lighter mesh but harder to do)

thanks a lot, the bevel and subdiv solved it, it was as simple as that, thanks again for the help

Try removing doubles by selecting all and pressing w then remove doubles.
Also,you have ngons which is automatically converted into triangles when rendering,so if it is not flat it will appear like this,

thanks for the insight, im a noob at blender and i was trying some hardsurface modelling,  someone told me ngons doesn´t have a lot of impact in hard surface, i´ll have to polish my technique

You can select the object, then go to it's mesh data properties. Then to Normals and turn on auto smooth. This will remove the triangulated mesh. Also set the auto smooth value accordingly.
Hope this helps.


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How to avoid overlaping corners on hard surface modeling?
i´m trying to model this armor piece but im getting overlaping geometry in some corners using bevel modifier with bevel weight and subsurf.

The only way i can manage to get rid of them is by adding edge loops but with that i can´t keep the roundness of my object.

Any help, advice or suggestions are much appreciated, thanks in advance.
If someone wants to take a look at the mesh in blender here´s a download link:
https://drive.google.com/open?id=1wat10y8BVTwcdP_rpkes6gixkH9rZwMn

This happens all the time to me too. I hope you find a solution.

i say it's the mirror and subdiv-suf modifiers, mess around with their positions in the stack. Mine seems fine though.


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Entered weird mode, tab switch between "Edit" and "Edit Strokes"

I did something I am not sure, but now Tab key switch between "Edit" and "Edit Strokes" mode without going out to the object mode. When I click the mode it says "Object Mode" but that's actually an edit mode. Also, all the armatures displayed in X-Ray are all gone. And edit mode does not show editable vertexes like it should be.
In this Edit Mode I can only try to right click around the area that I remembered there is an armature, the yellow name at bottom left would change accordingly without any other visual indication. I can press G to grab the invisible armature and move them. (I know this because it is showing Dx Dy Dz text)
One way I found to exit from this state is to load other workspace preset. But if I come back to this preset it still stuck in this state. What exactly is this?

I figured it out. I was in Local View mode. I didn't notice all the layer buttons are gone until I want to use it. In local view mode armature does not show.
I have no idea how I got in there because I have no numpad and I could not press numpad / to enter it, but luckily View > View Global/Local solve this.

this link might help
https://docs.blender.org/manual/de/dev/interface/grease_pencil/stroke_edit.html
if you want to get out of stroke edit mode try pressing d-tab


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Indirect Lighting is very slow proportional to vertex count even if they are not in the view

I have this library scene which is full of instanced group of the same model. The vert count says only 58, but when actually rendering it shoots to 1.7M due to all the books. However, the rendering is fast because Blender seems to exclude unseen objects.
However, when I turn on Indirect Lighting because I want it's effect, now the rendering time is exponentially higher. It seems to be longer proportional to vert count, even occluded ones.
Hiding some model is not an option since the camera will move around and eventually will reach the hidden part that I set. (Imagine a zooming all the way on this corridor)
Is there any solution to make indirect lighting calculate only the relevant model that matters in the current frame automatically, like the normal rendering without indirect lighting?
In this scene I even have a mist, so technically I can exclude everything further than the visible range. I thought things like setting camera's far clipping plane can help excluding things for Blender to consider but that is not the case. Rendering time is the same even with far plane as low as 100.

You are making wrong assumptions, something not being directly visible doesn't mean it is not contributing to the rendered pixels, in fact indirect light means exactly the opposite.
The walls out of view are still castings shadows in the visible ones, and the window behind the mist still lets light in even when you look away.
That is true for many direct light situations, even more so  with indirect light, all elements influence scene lighting everywhere, unless behind a watertight boundary.
Also Indirect light already calculates only relevant data as best as possible.
Some optimizations are done internally but it is not trivial to determine what contributes to a scene and what doesn't, more geometry will invariably make a render slower eventually.
If you want faster renders manually optimize your scene, reduce polygon counts, hide unnecessary stuff, simplify lightning, use instanced geometry wherever possible, reduce object count etc.
Also match your expectations to your hardware. If necessary bake lighting into textures to make animations faster.


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How can I use Network Render on viewport's "Rendered" mode?
I know that Blender can use Network Render to send jobs to several computers, but when working on a Cycles Renderer file I often switched to "Rendered" viewport shading to view the result as I move or spin around.
While somewhat viewable, I wish I can utilize other computer's (probably with good GPU) resource to iterate through samples faster in the same way as Network Render. Can I do this?

Do you need to see all the elements in your scene at once?  Can you focus on a few?

No that isn't an available feature. The network render only supports rendering final images.
The best you can do to speedup viewport rendering is to use the machine with the best GPU that can be used by cycles.
Other options include using border render to only render the part of the scene you are most interested in.


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Offsetting animation of group instances
For example, I made a rotating cube. I made 100 instances of this cube and place them all over the scene.
I don't want all of them to rotate completely on sync with each other. Maybe a randomized start time so it looked natural like separate entity. (But still the mesh and animation is linked, so I can edit the original one to update all of them) Is this possible in Blender?

It is not only possible, but also a common practice in the field of animating. You'll need to learn to use the following: action editor, NLA editor. For massive objects that can't be done manually through NLA editor, combine keyed actions with particle system instead.

One way is to use the animation nodes addon. In this example I take an fcurve from cube.001 and use a random number as a frame offset, then feed that into the rotation of each cube.

The nodes start with an object list that I filled with the selected objects and then hid the inputs in the advanced node settings. The loop input is used to apply the same node tree to each of the objects in the list


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How can I paint terrain with normal map?
How can I paint terrain with normal map? In texture paint mode I can choose one texture to paint, but what if I have a pair of texture? (color + bump)
For example I have a pebbles looping texture. It would be great if I could also make a big bump map as I paint the pebbles.


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How to find out the cause of a wrong weight paint?

I finished weight painting but when I begin animating, I found out that some vertex group is missing a weight or some vertex group might be accidentally applying weight to other unintended area. How to find out the vertex group that might be using a particular vertex without clicking each one and look at the color?

See this answer. With the vertex weight panel, you can at least select several vertices and see, which bone is affecting them. Also, you can copy weight setting from the active vertex to all selected vertices. This is helpful e.g. for the head, where you like to make sure that only one bone alone is affecting it.