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A strange crease appeared on my mesh after adding a loop cut
So I'm not exactly sure if it was a direct consequence of creating the loop cut, because it was only after editing (grabbing & moving) it around a little bit that I noticed the crease.
Anyway, here's a picture:

The loop cut I mentioned is selected in the picture.
I would really appreciate it if you could tell me how to solve this and make the surface smooth again.

You have inner faces, you can see it if you hide the outer faces, remove them:


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Is there a way to make these two objects seamless?
The colors of the bricks slightly don't line up, and I want the buildings to be modular, as I need to make a lot of them, is there any way to fix this?
(they use the same material btw)

Edit: I solved the problem! For anyone who also has this problem, the answer I came up with was to warp the main face texture horizontally  so every other grout lines up with the edge of the object, then flip the copy 180 degrees on the Z axis.

I solved the problem! For anyone who also has this problem, the answer I came up with was to warp the main face texture horizontally so every other grout lines up with the edge of the object, then flip the copy 180 degrees on the Z axis.

source: Stack Exchange

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

sort: votes


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edges appear in object mode in viewport after texture painting
After using the texture paint the edges of the mesh become visible in viewport in object mode. These edges don't show up in solid mode, but they do in every other texture mode.
I've checked the UV map to make sure the edges are fully covered. The edges also show up around parts that have no white around it at all on the UV map.
These white edges become more and more clear the further you zoom out and completely disappear if you get close. How can I make it so these edges don't show in object mode?

Same problem in a different topic (link)
Solution:

go to Shader Editor
change texture interpolation from Linear (default) to Closest (check the picture below)

Explanation from other topic:
The problem is caused by the interpolation caused by mipmaping. Linear interpolation kind of blurs the image causing the colors at the edges of the UV islands to blend thus making the seams show up.
If you are not going to export the model with the texture then the proposed solution above works perfectly. For all other cases turn up the bleeding when painting or scale down a bit your UVs when editing.

More info about bleeding if you are not yet familiar with it can be found here at 8:35.

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


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Blender file won't open
When I open my file, Blender opens for a second (as shown below) and then closes.

What does the console say? It is probably telling you what the error is...just look at the other Blender window. Also, what version of Blender are you using? From the image I notice that it is in a folder with -'s in it which could potentially cause problems on Windows...also that path looks very suspicious to me anyhow...

i'm using the version 2.79b.i can't understand the console(it's the picture above).

That error is fine...I have always had that message on any OS. Perhaps this is a permissions error, so you could check if you have read/write access to that file. Otherwise, start it from the console with C:\Program Files\Blender Foundation\Blender\blender.exe -d (or wherever Blender is installed, just make sure to use the -d debug flag) and post the output.

the read/write access to that file is okey.Someone told me that i maybe pressed a wrong key and corrupted my file is there any way to fix it??

There is often no easy way to fix a corrupted file, but try what I mentioned in the last comment to see if that says anything useful...

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


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SVG from illustrator doesnt fill correctly
Blender is not filling correctly the SVG file imported from illustrator even after trying all the options for SVG exporting on illustrator. On the attached photo, you can see the area referred with the blue arrow doesn't fill until I delete the red areas.
The filling before deleting the red areas:

The filling after deleting the red areas:

Would you please help me sort this out?

https://blender.stackexchange.com/questions/47217/extrude-and-bevel-an-imported-svg-curve/47220#47220 https://blender.stackexchange.com/questions/52825/svg-curve-incorrectly-rendered/52875#52875 https://blender.stackexchange.com/questions/47825/extruding-vector-files-in-blender/47829#47829

@DuarteFarrajotaRamos Thank you for your comment but my SVG file doesnt have intersected / overlapped curves. I have already combined them into one path in illustrator.

@DuarteFarrajotaRamos Looking at your second link... Yes there have been some overlapping nodes and some weirdly oriented handles. I have smoothed some areas out. everything is okay now. Thank you!


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Convert 2d path to 3d bracelet
I usually use Photoshop to convert a 2d path to 3d object but I am not able to fold it to make it take a bracelet shape like the one in the . I was wondering if Blender can do this and I really appreciate it if someone can explain it to me. Let us say the length of the bracelet is 6 inches. I can make a 6-inch length path but how can I fold it into a bracelet shape. If my question is not clear please ask questions.
Edit1:
Thank you for the answers. I am going through @Robin_Betts steps. Every thing went fine until I came to step 4. The rotation doesnt go as expected. PLease have a look at the photos.

Edit2:
I am almost done, still have a small problem. There is a plain that appears when I rotate the curve. What is the reason for that?

Conclusion:
Yes! Everything looks good now. I have just removed doubles. Thank you all!
Side Notes:
1- I have repeated X > Limited Dissolve mentioned in step one about 10 times to make the curve clean and made 400 cuts for the plain mentioned in step 2.
2- I have rotated the objects (step 4) in object mode (Rotating the mesh in Edit mode didn't work for me)
3- I couldn't rotate the objects around Z axis until I created an Empty object and use it as an Axis/Origin.

See edit to step 4. Bend axes are confusing, even after playing with them for a while .There's a difference between rotating an object's mesh, in edit mode, leaving the object's transform unchanged, and rotating the object (modifiying its transform matrix.) Hope this starts to clarify the answer.

On the rotations.. as stated, my example started out flat in the XY plane, and then was rotated in Edit Mode.. If you started in a different orientation, then different rotations will get the desired bend. The Simple Deform modifier interpolates its effect  along the object's local X axis unless you override it with an empty, as you have. Glad everything worked out in the end.

I don't really want to duplicate @moonboots' answer.. this one takes a slightly different approach, and may help with some intermediate steps for a beginner.

Working in the XY plane, X across.

Import your svg, and convert with AltC to a mesh. The mesh may be a bit messy, with a lot of edges that don't contribute to its shape or integrity. In Edit Mode, X > Limited Dissolve will get rid of a lot of surplus edges, by angle.
Create a plane that covers the geometry, and move it up in Z. Hovering over one of the long edges,  CtrlR > scroll to introduce enough edge loops across the plane to allow for deformation. X Delete > Only Faces to leave yourself with a wire frame.
In Object mode, select the plane, and then the path-mesh. Put the path-mesh into Edit Mode. In the tool region, find 'Knife Project'. Looking straight down Z in an orthogonal view, hit the button. This will project the plane's edges into the path-mesh.

Having rotated the whole mesh in Edit Mode, by 90 degrees in X so it's standing up on XY, assign a Simple Deform > Bend modifier, axis Z, 360 degrees.

This is what the rotation should look like, illustrated with the Transform Orientation set to 'Local', so the Gizmo shows the object's local axes. Note they are still coincident with the Global axes. (If they are not, you can hit Ctrl A > Apply Rotation)

Now you can apply the modifier and edit the mesh to join its ends (the small blue wedge in the picture). Use F or Bridge Edge Loops  between two edges to create a new face.
Now you can assign a Solidify modifier to give it thickness.

This example is quite low-resolution, you could use more divisions in the plane in step 2.
You can apply the Solidify modifier, and go in again with a Limited Dissolve,  adjusting the angle to tidy up as much as possible without losing detail
The topology is horrible for smooth shading or subdivision, but that's not what it's for. In Edit Mode, CtrlAltShiftM selects no edges, showing the object is manifold, and should print.

oh yes the knife project tool is a nice trick

Thank you for your answer, this is exactly what I am looking for. I have a problem regarding step 4. I have added some photos to the question please have a look.

@Robin Thank you very much I am almost done. Would you please look at Edit2 in the question?

Finally everything is alright, problem solved.

If you just want to bend your shape 360°, the easiest way to do it in my opinion is to use the Simple Deform modifier:

First convert your svg to a mesh with a altC > Mesh From Curve.
Make sure that the topology is correct: that it is simple, that you have enough vertical edge loops so that it will bend nicely, and that it will be easy to add edge loops.
Extrude it to give it a bit of thickness, delete the face on each extremity.
Give your object a Simple Deform modifier / Bend mode, choose an Angle of 360°.
When you're glad, apply the modifier and remove doubles.

I just thought I would expand on this a bit.. I hope there's no offence.

of course not  ;)


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How can I smooth the top side of this ring?
I want to smooth the top side of this ring:

This is how it looks like after rendering:

The mesh of the top side of the ring is very obvious in the rendered image and basically this is my problem.
I am a beginner in Blender but I have tried everything I know. First off, I have made the selection of the top side of the ring manually in edit mode because couldn't find an easier way. Then, I have tried to subdevide the selection but it won't subdevide anything except for some faces. I have tried ctrl+R to make cuts but it doesn't work.
The ring is the result of an extruded 2D vector and then sliced vertically using Knife project tool and then bent 360 degrees using simple deform modifier
My question is how can I smooth just the top side of the ring without the edges?

Sounds like you may have duplicate vertices, so remove them first. Then you can either subdivide, bevel and/or select smooth shading for the selected faces.

@gtzkw I have already removed duplicates but subdivide still didn't work for most of the selected faces. I have tried smooth shading for the selected faces but it makes the face unrealistically smooth. Can I control how much smooth the selected faces should be?

By the looks of it the topology is really bad, ngons and possibly disconnected face, which is why subsurf doesn't work. For the other part see @moonboots answer.

I guess you have these 2 solutions:

Smooth your object in the Tools panel, and in the Properties panel > Data > Normals, enable Auto-Smooth, set the value under which the angles smooth.

Create a bevel all along the angles, thin enough to keep them sharp, it may need a bit of knife work if you have triangles or ngons. After that, smooth your object in the Tools panel, and give it a Subdivision Surface modifier. If you're supposed to 3D print the object, I guess you just need to apply the Subsurf.

Thank you the first option worked for me. Do you know how can I make the selection (top of the ring) in an easier way. I have made the selection manually using the Circle tool.

if your topology was good you could do it with a simple edge loop select (alt + left-click), but as the series of faces on the top are not always quads (I see some triangles and ngons) edge loop select can't work properly, so I'm not sure there's any easy solution, except fixing this and making only quads on the top. A trick that could help though: once you've selected all these faces, you can create a vertex group so that next time you don't have to reselect them manually.

I'm sure there was a way to make a good topology from the start but I guess it's another topic   ;)

that said you could try to select one of the top faces, and press shift G (Select Similar) > Normals, then play with the parameter (threshold), it might work to a certain extent

Relatively straightforward with a couple of modifiers.
I did this freehand but you would be better with a reference image and taking more time but the process would be the same.
Imagine the shape cut in half and flat.

Make sure the pivot is on the right hand side and that the verts on the right line up with a scale to zero on the x in the image shown.
Add a mirror modifier and apply followed by some extra edge cuts as shown

Add a bend deformer and wrap the object 360 degrees

In edit mode extrude the shape x 3 making sure the first and last extrude are shallow giving a supporting edge.

Add a subsurf modifier x 2 and adjust verts as required.

This process will work the same with your reference.


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Problems creating keyframes with low fps in blender
I'm starting to tinker a bit with blender development and I'm creating my first animations in blender through keyframes, but I'm having some problems when it comes to setting up the animations...
I have an intel i7 processor and a 3060 graphics card.
Generating a flat object, simple and indicating in tools like ocean and selecting a resolution of 30, when I generate keyframes does not exceed 0.20 fps, I understand that this is for configuration issues but I do not understand much how I can improve the performance or if you really need something more powerful to simulate the movement that I seek.

The resolution of ocean is to high even for your setup. For realtime animation it's better to use the value <15

Would you need a more powerful device? Okay, thank you very much for the recommendation on the value I should apply.

I don't have the opportunity to test ocean modifier on better setup. I tested it on mine 2070 Super which basicly has the same stats as yours 3060, and as I said <15 value was OK)

OK, perfect, thank you very much Yuri !!


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How do you make the MGM filmstrip ribbon in Blender?

This is what I'm trying to talk about. Are there any possible ways to recreate the ribbon, complete with the holes, surrounding Leo the Lion in the MGM logo?

And you did try what? Or do you want us to make all the work for you?

Hi :). There sure are. But please show what you tried so far and where exactly you're stuck :). As Chris said, this site isn't meant for full tutorials.

create a curve for your ribbon

create a plane, subdivide it a few times

create a cube as the hole like this:

add empty in 0/0/0 and a mirror modifier for cube

add boolean modifier for plane, make cube invisible:

add array modifier to plane, fit curve, choose curve

add curve modifier with your curve to your plane

add material

i hope you know how to add a picture...if not, please ask another question (you can ask as many questions as you like)


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Geometry Nodes - Scattering inside a scattered object (using vertex groups)
First time asking a question here ! woo.
I've tried to look for an answer.. I must be missing something very basic.
I started using Geometry nodes a few days ago (finally)
I'm trying to scatters stuff on instances by vertex group located on those instances

So we have those "building01" and  "antenna01" objects
I scattered building01 using a vertex group on the ground plan then random rotation, all good.
Now, i want to scatter those antennas on the top of those building01 instances.
On the building01 object i defined a vertex group called "roof"

First i tried to make it all with one geometry node but i cannot access the "roof" vertex group.
-I tried to stack TWO geometry nodes modifiers (one for the first scatter of building01 and a second one for antenna01). But that just... don't work.
-I tried to make a geometry node for the building01 object, i can scatter antenna01 but just like shown on my screen capture all the instances are identical. Which of course makes sense...
Realize instances doesn't help because i can't access the vertex group on building01 anyway :(

That's it.. actually.
This is a very simple example but then i could have complex buildings bases and scatter/display stuff on them using vertex groups. like antennas on roof , pipes on wall, etc.
Thank you everyone
Blend file :

welcome to SE! pls add blend file because you didn't include the gn node group for both modifiers and it is much easier for us understanding and trying out things. thank you! you can upload blend file by opening https://blend-exchange.com/ and following instructions

Thanks and  right ! ok i just uploaded the .blend

i am not sure what you want to achieve now? more antennas on the roof? just change distribute to this: [1]: https://i.sstatic.net/bGUGb.png result: [1]: https://i.sstatic.net/MmRaJ.jpg

Actually i want to scatter antennas on the roof , of each building... but for every building their numbers and distribution should be different. Also now, the antennas are scaled with the building since i changed their scales. Basically, 1) first scattering : the buildings  2) second scattering : the antennas but only on the roof (defined by vertex group "roof" on the building01 object.  Do you see what i'm trying to achieve here ? Sorry if i wasn't clear earlier

Instances are objects that's share the same object data. In other words, you can't make different instances, because they just the same. Take a look at Alt + D copies. They are linked, they are instances of the same data, and if you change one of them - the second will be changed also.
Instead of making the building and when distribute it on the surface, do the opposite thing: distribute buildings, realize them and put antennas on the top:

Realize instances doesn't help because i can't access the vertex group
on building01 anyway

No, you can. In 3.2 there is a Named Attribute node, that allows to get access to vertex groups

Thank you !!!! That's exactly what i wanted to have... "Named Attribute node" got it !! yesss !


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Is there a way to render grease pencil without the reference object
I made a cube and added a grease pencil stroke to create a line art of the cube. Now i turned the cube off in the renderd image to just render the grease pencil stroke lineart of the cube. No lineart is displayed at the rendered image. Can someone help me?

Solved: I have to bake the lineart.

Use a holdout shader:

The Holdout shader node is used to create a “hole” in the image with zero alpha transparency, which is useful for compositing (see Alpha Channel).
Source: Holdout — Blender Manual

This will hide everything behind the object as well, which can be intended, or not, or irrelevant for OP.

Yes, in which case the other answer covers it all ;)

If you don't want to bake the Line Art for various reasons, you could simply give the cube a Transparent BSDF set to full white as a material, this way it's invisible in the render but the lines still show. The other possibility would be to disable everything under Visibility > Ray Visibility in the cube's Object Properties.

option: give the cube a material to make it invisible

option: disable all Ray Visibility settings


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The chain is breaking apart
I've designed a chain using Rhino 3D and would like to attach it to a mannequin. I've imported the mannequin and chain into Blender. I would like to activate gravity and have the necklace lay on the mannequin by the effect of gravity. I've used rigid body for the chain and set the shape to mesh. The chain breaks apart and the scene is very laggy. My goal is only to attach the chain to the mannequin. I won't make any animations. Is there a simple way to do that? I am completely Blender beginner. Here is a link to the file . Thank you in advance.

Update1:

In this case IT IS probably better to use a mesh line with a cloth modifier and use it as dummy for Your neckles with Mesh Deform modifier - target to mesh line. https://blender.stackexchange.com/a/239405/2214 oř here https://blender.stackexchange.com/a/229467/2214

Oř here just without Bones https://blender.stackexchange.com/a/228398/2214

So much to learn! I will do my best and get back.

I am not sure what I did wrong. Here is what I did. I've joint all chain links and pendants into one object called necklace. I've drawn a bezier line along the chain and converted it to a pipe shape using Bevel round and then converted the pipe to a mesh. Then I applied Mesh Deform modifier to necklace mesh and chose the pipe mesh as the midifier. Please have a look at the result above.

Using physics (for such kind of model) will be too heavy to calculate (each segment of your chain with each others on line) and full of errors (penetration, interruptions, etc.) I don't think there is an easy way in blender just use your model directly in blender an succeed with Rigid Body sim.
... for that I'm suggesting you to

model a "dummy" of your necklace
add Cloth Sim modifier to it (to minimise mentioned issues)
and use it as Target for Surface Deform modifier added to your hires model.

Here I created a dummy object ... place a face under the name and with edge selected, hold Ctrl and click in chain direction to generate a square face. Continue to follow chain shape around to cover whole hires model.

Assign Cloth modifier (default setup seems to be fine)
Than select your necklace and add Surface Deform modifier with Target to dummy ...

Because rings holding names were squeezed so I separated names as solo objects and used Parent to Vertex feature to stick to dummy. just select name object than dummy switch to edit mode select three vertices in triangles position (one that is in ring location) and Ctrl+P.
Result

Your file is big I tried it to simplified, but still big so take it from here (no need to login, there is a direct link to download at the bottom of popup window - black text).

Thank you for your effort. I am still struggling to make this work. Would you please recommend a course I can take to help me with this? Maybe on Udemy or another platform.

I dont know what is your specific issue you are dealing with, so it is hard to recomemnd any tutorial. You can edit your Q by adding more details about current issue or ask completely a new Q ... if you have an issue to use modifier search for some tuts.

What I need to learn is putting any type of necklace (imported from Rhino) on a mannequin under the effect of gravity. The necklace could have a name plate, a charm or multiple charms...etc. So, it is something related to physics and animation more than 3d modeling.

Thank you! The result is much better, but why the chain is not touching the mannequin? It is floating. Can it be solved by decreasing the size of the dummy surface?

I'm on tablet now ... So just guessing ... In Collision properties Distance or Margin should be set lower ... Or so, I will check that tomorrow if you don't succeed.


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Making a Custom Operator Window Continue to be on top, blender python
With the below code I am able to create window. But when I click on viewport the windows doesn’t stay on top and it goes off. I want to stay the window unless I close by clicking on OK button.
class MyOperator(bpy.types.Operator):
    bl_idname = "object.my_operator"
    bl_label = "My Operator"

    def execute(self, context):
        # Do some action here
        return {'FINISHED'}

    def invoke(self, context, event):
        wm = context.window_manager
        return wm.invoke_props_dialog(self)

     def draw(self, context):
         layout = self.layout
         col = layout.column()
         col.label(text="Select an action:")
         col.operator("mesh.primitive_cube_add")
         col.operator("mesh.primitive_uv_sphere_add")

def register():
    bpy.utils.register_class(MyOperator)

def unregister():
    bpy.utils.unregister_class(MyOperator)

if __name__ == "__main__":
    register()

    # Test the operator
    bpy.ops.object.my_operator('INVOKE_DEFAULT')

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.

I have added additional details on what exactly the requirement is.


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Smooth selection along a curve
I would like to know how I can make a smooth selection along a curve (like proportional editing object mode).
If i use proportional editing object mode with a spiral and a large radius of smoothness the tool will grab the turn under the one selected which i don't want.
I want to grab one end of my spiral and deform it along it own curve.
... hope I'm clear enough :D
Many thx

In the proportional editing choose "Connected".

https://blender.stackexchange.com/questions/56396/logarithmic-curve-with-spiralling-cross-section/56398#56398

Maybe a better way of deforming a spiral along a curve, though, is to use a Curve modifier?

Connected do exactly what I was looking for! Thx!


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Make holes with boolean not working - blender 2.8
I use Blender 2.8 and I made a lot of successful holes with the boolean modifier. Today is not one of those days and I don't know why.
I have a simple rectangular 2D object in which I need to cut 4 cylindrical holes.
This is what I have done:

I've used CTRL+R to make new lines on the rectangle that intersect exactly where I should place the holes
I moved the cursor to each point and created a cylinder
CTRL+J to make a single object from the 4 cylinders
I used a boolean modifier on the rectangle and applied it to the cylinder with the operation "Difference" but I didn't get the holes

This is the Blender file:
What have I done wrong? Is there a way to place the cylinders exactly where they should be without using CTRL+R? If I don't use CTRL+R the holes get done but then they are not in the right place...
Thank you.

Please use https://blend-exchange.giantcowfilms.com/ for uploading files. As your question doesn't have any images it solely depends on the file attached. Hence if the file is gone the question isn't clear any more. Better yet include a screenshot of the model additionally to the file

https://blend-exchange.giantcowfilms.com/ doesn't seem to work, it says. It writes "Files may take some time to process" but 5 minutes have passed since I try to upload a 600KB file.

Press Upload button first... That is warning, not a process description

Boolean modifier -> turn overlap threshold all the way down to 0. Since your objects are so small in the scene blender considered the faces as overlapping (i.e your rectangle was too thin).

It didn't worked only 2 out of 4 holes got made after turning threshold to 0. I also tried to increase the size of the objects 100 times and still the holes didn't appeared.

also your boolean modifier wasn't targeted in your file

I targeted the cylinders right before pressing apply. I updated the file from the link with the objects resized and the cylinders targeted in the boolean modifier.

I solved the problem but I don't think is the right way: I deleted all the lines that I created using CTRL+R and the boolean modifier started to work. I actually made the lines disappear by selecting all the faces from that side of the rectangular object and pressing "Dissolve faces"


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Associating photos to the faces of a cube
So... I am a beginner in blender and I want to associate those pictures to the faces of the cube, just that they won't show up when I am in the render view. I've watched a few tutorials but still can't make it... Can anybody help me? I want to export the cube in unity.

Edit: On a second try... the cube looks perfect blender just how i want it... but on render mode it looks like this https://i.sstatic.net/r8sdB.jpg and if I import it to unity it is just a blue cube... Help?

Are you rendering in Cycles or Blender internal?

please specify which tutorial so to understand which workflow you followed...

https://www.youtube.com/watch?v=vpyjqaiE0HI&feature=youtu.be
That's what i followed. When i Use the texture view everything is fine but when I use the render view it shows up like this.

To see a texture you have applied to a model, you should simply change your Viewport Shading.

You will now see the textures you have applied to the cube.
To make them applied in your Unity3D game, you will need to obviously add it to Unity3D and it will look the same as it did when you used the 'Texture' Viewport Shading.

This doesnt help me...

Try to use "Smart UV Map Project" in "UV Mapping" mode and texture out the UV map.  A more detailed answer on how to do that: https://blender.stackexchange.com/questions/100703/how-do-i-insert-a-picture-directly-onto-the-face-of-a-cube/100707#100707

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


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Surface rendered with a different blur frame by frame
I'm using Blender 2.79 to render an animation. While many frames look consistent, every three or four frames, a series of frames crop up where a surface is rendered differently than the rest, often with what appears to be a depth of field blur in a different place. See the differences frame by frame with the ground surface here:

The first image is correct and the rest not correct.
I'm using a camera with a cube as a depth of field focus object, if that matters. Also using denoising, which doesn't seem to be the issue, and the fracture modifier for destruction. There is only one light in the scene that does not move.
Any hope for making the frames more consistent?

I'm not sure what you mean by "crop up". Do you mean that a specific glass shard isn't in focus as it's supposed to? Do you have the depth of field focus object at a static location or is it animated as well?

The depth of field focus object is static. The glass shards appear as expected; it's the floor that isn't consistent frame to frame. It's as if parts of the floor are flickering in and out of focus. See the difference in the rendering of the floor from frame to frame above.

I see what you mean. What is that catching the reflection on the floor in the first render a texture or simulated water?

The floor has a texture fed into the Normal of an Anisotropic BSDF as well as the material's displacement. That's what the "scratched" effect is on the floor. Is that what you're referring to?

Yes. Unfortunately I'm not sure what's causing this. Do you have caustics enabled? Does it make a difference when it's disabled?

I disabled Reflective Caustics and Refractive Caustics with no improvement on the problematic frames. Filter Glossy was at 0.5—checking to see if it helps to bring it down to 0. I attached the .blend.

Zeroing out Filter Glossy does nothing! So strange.

If you re-render affected frames with a different sampling seed, does the effect disappear/ change? Could it just be unlucky samples on something that is hard to hit?

I could reproduce the problem in 2.79b, but it doesn't seem to happen in Blender 2.8.

Changing the sampling seed doesn't seem to help. I found a Windows version of Blender 2.8 with fracture modifier, but it didn't maintain my fracture settings. Did you find a solution that maintains a 2.79 fracture modifier, @rjg ?

No, sorry I don't. If you're up to a little tinkering, you could render the glass in 2.79b and composite with the sequence of the ground rendered in 2.8.

Whatever the issue was, it was resolved by re-rendering the whole project with a version of Blender 2.8 with Fracture Modifier (rather than 2.79b). Thanks to rjg for the suggestion!


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How to generate an animated tie dye-like gradient as a texture?
I'm trying to generate an animated texture that looks something like the "LUMP CANDY" text in the logo of this image:

I've found some animated gradient solutions here, but I haven't been able to generate a texture with some of the default procedural texture options in Blender that looks quite like the image. Any ideas?
EDIT: I ended up adapting one of the textures from this thread—the one in "Cycles Procedural Texture Pack # 5" at the top left. This was the result:

You could try to use the Wave Texture node, then play with its Distortion value and with parameters of the Mapping node:


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Random line in smooth shading?
Flat shading and even Auto-Smooth Shading works completely fine. It's just Smooth Shading that seems broken. The blueish coloured topology with the broken shading is applied with the following modifiers: Mirror, Subdivision Surface, Shrinkwrap. It is shrinkwrapped to the sculpted model below it (greenish colour). I was working in flat shading and switched over to smooth shading only to find this. I closed and opened the program and that did nothing. There's no overlapping vertices that I can see, it just decided to shade it weird idk.

It looks like you have normals flipped in that area - reset by selecting the whole mesh in edit mode, then pressing Shift+N (Recalculate Normals Outside).

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.


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Morph linear graph to log graph by distorting UVs?
Hi Blender enthusiasts.
I've been trying to understand how the ffmpeg shoswpectrumpic function works. It allows you to generate a spectrogram from an audio file using either a linear, or logarithmic scale for the frequency.
I've generated a tone getting higher at a constant rate, and generated 2 spectrograms from it :

one using a linear scale for the frequency
and another with a log scale

I want to understand what kind of operation ffmpeg applies when using the "log" option.
My idea is to distort the Y axis on the UVmap so I can 'morph' the linear image to the log image. But I don't know what operation I should apply to go from linear to log ?

If you have any idea of how to approach this problem please share, I've been at it for hours...
Here's my blend file :
edit : ok I've found an operation that seems to work, but I don't understand why...

The operation goes like this :
y = 10^(-3*(1-y))

Anybody knows why this particular operation works ?

Have you tried the logarithm operation in the math node?

I tried it and it does curves the UVs, but it goes the wrong way, and the curve doesn't match the one I'm trying to copy...

Your file has been deleted, can you share it again? https://blend-exchange.com/

Thanks @taiyo it should be good now !


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Geometry Nodes : set position based on distorted UVs
I've been fighting with this for hours and can't wrap my head around it.
I am using geo nodes to distort the U axis of some UVs using a float curve. I then use the distorted UVs to display an image. The result looks like this :

My goal is to be able to move points along a line so it follows the UV distortion. But if I use the distorted UVs as is to set the points position, this moves the points in the opposite direction.

And this is normal, this is how UVs work : lower U value means "image going to the right", as for position, lower values means "points moving to the left".
So as I understand it, I need to reproduce how UV sampling works :

first sample the distorted U axis
then find the correct position along the curve from the sampled value

Ex : if the distortion gives me a value of 0.05, I need to find where along the U axis is there a value of 0.05, and extract a position from that.
The problem is, I have no clue how to do so. I tried using the "Sample Curve" node, but to no avail.
Here's what my node tree looks like for now :

And here's the blend file :

Any help is welcome. Thanks for reading !
edit : added blend file

Why not simply move the vertices of the grid, instead of updating the UV? It would have the same visual effect, and you would move the points of the indicator below in the same exact way as you moved vertices…

@MarkusvonBroady Thanks for your answer. I would if I could, but this is only part of a more complex project, which demands the UVs to be distorted :/ I like your idea though, I'll see if I can somehow change the process.


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Bevel not beveling in some cases - message is nothing selected
I use blender 2.8, this is my first project.
Problem is that I can not bevel in some cases.
I'm in edit mode, I select an edge and press CTRL+B and when I try to move the mouse to bevel I receive the message "Nothing selected" like in the image.
The blender file is here.

You have 2 problems that prevent you to create any bevel:

An inner face that you need to delete.
A flipped normal, select all and press shiftN to fix it.

Now it works.


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tapering a custom object
I took an flat image of a fish fin and used image J to convert it to a series of points which I connected. I extruded it from 2D image to 3D in inventor, and converted that ipt file to an stl file. I uploaded this into blender and want to taper the edges of the fin so that it is not a completely flat object.
I am trying to resemble a real fish fin in life which is thicker at the base and then thins out as you reach the tip. I have no experience with blender and limited modelling experience. Is there a way to taper the edges on an imported stl object? All the videos I saw on youtube used circular objects and were able to use the taper tool but my object is not cylindrical. The option to taper does not show up for me.
Another way is to just upload the 2D points into blender and perform the extrusion in blender instead of importing an extruded fin. I have the points in an excel sheet but I would have to convert them into a python array. Which I don't know how to do.

Could you briefly explain what you mean by start over, without using specialized language? Should I import the points via python array (I don't know how to switch xlsx into python array) and then connect the points as a curve? The post referring to the blade tapers it the wrong way for me. I want to like vary the width of the fin as it goes from base to tip, not a constant taper between two uneven faces of the fin (if that makes sense).


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Punch a face on a model to the first backface of the model and make a hole
I have a model where i need to make a lot of holes. The kind of the problem is in all of them the same. The position and size of the hole(s) is already set by a face and they should not change. So what i need to do is to punch the face through the part of the model to a backface.
Here is an simplified illustration of the problem:

Update1: I don't have a separate mesh to make holes.
Update2: I have this problem probably more than 30 times in my mesh. So doing an extrusion, deleting backface, punching hole, recreating the backfaces, making the tunnel is unpythonic. Is there a shortcut for this?

The difference is i don't have a separate mesh.

Most if not all solutions presented there can be applied here. This is such a basic problem, that you probably wouldn't even need those. I suggest you try the Boolean approach as it is the easiest and gives you visual feedback how it works. My solution would be to extrude the face marking the hole to the other side of the first wall, delete the large face and then create faces as on the outside.

Inset both faces of the part of the cube through which hole should be cut (one of those faces is in place already on screenshot above), move insetted faces down where need be, run Bridge Edge Loops operator (all without deselecting the insetted faces), that should be it


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Bezier Curve. following but not in sync
Alright so, it follows the curve but they wont follow in line, they will all rotate at the same time not following the line, the primary will follow it but the rest in the array will copy the first and not follow the array correctly.

Im going to assume no one is going to give me assistance... Why did i ever ask on this website then

Just added picture

move the array modifier above the curve modifier

Omg i got an answer holy cow, 36 minutes later, Thank you.

If you want quicker answers, please consider being more specific in your question. Guidelines here: https://blender.stackexchange.com/help/how-to-ask


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Issue with UV mapping and Texture paint tools
I'm very new to Blender so sorry if this is quite obvious. I've been using Darrin Lile's character modelling tutorials on YouTube. It was all fine up until texturing. To briefly explain what the issue is, when using the 'Texture Paint' mode in Blender (the one that allows you to paint directly onto the object), the paint is appearing on the opposite side of some parts. For example, if I add paint onto the stomach, it will appear on the character's back.
I'm hoping the solution is something very simple but it's possible I've messed something up with the UV maps. However, my UV map seemed fine.
If anyone could help with this that would be great. Thanks for reading!
Here's the download link to my model:

do you mean it also appears on another part? It would mean that some parts of your UVmap are overlapping

Can you check in edit mode that your mesh face normals are all pointed outward? This is a common problem where texture paint is on the 'wrong side' of the mesh at times due to the normals needing to be corrected.

Hi @moonboots, thanks for the answer. I can confirm that occasionally the paint appears on multiple parts. I think I can recall the tutorial I was using suggesting a way to move the UV islands around so I'll see what I can do and get back to you on that.

for a direct painting on texture, when you unwrap, use the Smart UV Project option, it will create islands that won't overlap by default, then paint on the 3D view (or UV/Image Editor)

Hi @CraigDJones, thanks for the answer. Sorry, I'm not really too sure what you mean exactly by that. If you mean, is the paint appearing on the inside of the model aswell, then yes it is.

Hi again @moonboots. Sadly that hasn't quite worked. I've tried using the smart uv project option as well as the average island scale and pack islands options. I can also confirm there are no overlaps. Still when i paint on one side of the model it appears on the other side. Also for some reason, the paint ends up on some other objects that have a different uv map and are not selected. If it helps I'm also using the mirror modifier, but don't think that would be the problem. Thanks again for responding.

oh ok so apply the Mirror modifier and see if it works   ;)

@moonboots Sadly still no positive results :(

have you unwrapped again after applying the mirror? maybe share your file...

@moonboots Just applied the mirror and then unwrapped it again but still same result. I'd gladly share the file but... having a few technical difficulties with the internet on my PC currently. When the internet finally comes back up where should I send you the file? Assuming that I can't send it on this discussion page. Thanks!

put here on this page: https://blend-exchange.giantcowfilms.com/   enter the URL of this page and then upload

@moonboots Think that should be it uploaded and here's the link  I'll put that in the question description as well. Thanks very much for taking your time to look into this, and there's no need to rush at all!

oh ok you need to recalculate your normals: in Edit mode select all and ctrl N. By the way you have a lot of faces, you should simplify a bit  ;)

@moonboots Ah yeah that did it. Knew it would be something so simple, thanks so much! :D

It's a Normal issue: Go in Edit mode, select all, and press ctrlN to recalculate the normals (shiftN in 2.8).

ok I correct my answer


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Physics with an object made of several parts
I am trying to throw a die made of several parts that must stay fixed. The purpose is to get a realistic physical behavior.
What I tried :
The small parts have an object constraint : Child of set to the biggest part.
Their rigid bodies are set as passive. The parts are not overlapping.
What I get :
The die jumps at the beginning of the animation ... as if a collision was  detected ...
Thank you to suggest a way to do this ... even if it is radically different from what I tried.  :)
Thanks
![die]https://ibb.co/Twyzj6v

How does your setup differ from throwing a normal die and parenting the different parts to the box collider?

A screenshot of the die setup would be useful to understand exactly what is going on.

@Sazerac      https://ibb.co/0yVqRjC   ...   (tell me if there is a better way to show an image in comments)   I made this image in Photoshop to show the settings of Dé (the die ... which is not a cube as you see) and Vitre (one of the small parts

Edit your post and include the image.

create a cube the size of the die, make the cube not rendered and then use it as a rigid body physics and parent the die pieces to it

Thanks, but won't Blender use the envelope of the cube to calculate the physics ?


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0 ->1 Soft Transition node : Steepness is clamped along a curve
I often need a soft 0 -> 1  transition function. So I made it using this mathematical fuction :
(a) parameter determines the speed of the transition ( its steepness )
(b) parameter determines where the transition occures.

Here it is turned into a node :

Then I tried to use it to compute the radius of a curve to make it softly transition between 0 & 1 :

Strangely, it is as if the "Transition Speed" parameter was clamped. All I get is a very slow transition. And I couldn't debug it :

If I increase the "Transition Speed" parameter, it stops having any effect above 9.
In fact it is a very useful node ( and it could be native ) ... so solving this would be great.
File :

Thanks for your help !

You have a default Bezier Curve which has only 2 control points. Check it in Edit mode. Since the x shift is 0.5 (=center of the curve), the first point gets a radius of 0.0 and the end point gets a radius of 1.0. It works as designed! :-)
I guess you expect something like the following. For this you need more control points (=more x values):

Try a Resample Curve node with Count 50. To see the effect more clearly, you can also add a Map Range node to scale the 0.0-1.0 range to a wider range. (A curve with a radius of 0.0 is not visible).

Thanks Blunder !  Now my question seems ridiculous.   ... the radius is evaluated on control points and only there ...


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Link : Use ojects and baked simulation in another .blend
I made a simulation with a bunch of objects and rigid body constraints in file1.blend.
I would like to use it in another file (file2.blend).
I guess I need to link the object and the baked simulation. ( Note that I couldn't find the bake options in my 2.82 version, for instance the Use Library Path option ).
I could use some help ...
Thanks !

You are right Jachym. Sorry for the delay.

You can use Collection Instances for that.

Put all your simulation objects inside a Collection
Link that Collection into another file (using File > Link). That will create an Instance.
Move your linked Collection Instance as one object

Linked simulation from another file then behaves like one object.

Thanks for your answer Jachym, Points 1, 2, 3 are ok. But the linked object is motionless in File2, although simulation works and is baked in File1.

Hi :). Would you mind sharing the files? I'd like to take a closer look at what might be wrong :).

That's really kind of you. First file with the simulation :     Second file that imports the simulation :     ( It was too big, I had to remove almost everything ... except the important for us ) ... one minute please ...

Here is the second file :

Hello :). Please post it as a new question, add the files and somebody will surely help :). There are many people waaay more skilled than me.


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Geonode : Display instances scales as text
I need to display a bunch of fish instances with randomized scale.

They are generated with geonodes.
Under each fish, I need to display its ( randomly generated ) scale.
As you may know using a random value to feed a  {value to string} node generates an error.

Here, the string to curve would generate a text instance to be displayed under its corresponding fish.
Now I still can enter all scales manually ... but ... but ... you know.
Any idea to solve this problem ?
Thanks !

Since the Value to String Node only accepts a single value, this currently does not seem to work in GN. But there is at least a solution with the (free) Animation Nodes Addon, which can be linked to GN: https://blender.stackexchange.com/questions/251470/is-it-possible-to-generate-a-row-sequence-of-numbers-with-text-nodes-without-hav

Thanks Lars, but my problem is not to display a random number only. This number must also be the scale of my fish. Ad I don't see how I can use your solution to connect scale and text

Yes, I had assumed that there is some way to pass a 'scale' value/field/attribute from AN to GN and back, but I must admit I didn't check it thoroughly. Maybe my answer below is of some use?

Here is another solution...
This may look cumbersome (to be honest it is), but basically this solution is relatively simple.
Since Geometry Nodes can only create text with the String to Curves node, which does not accept fields as input, you would have to do the following:

Since the String to Curves node outputs each digit as an instance, simply create the numbers $0-9$ as well as the dot and reset their position to $(0,0,0)$.
Then simply instantiate curves at the desired points, which themselves consist of as many points as the number of digits of your numbers (in this example I use four digits, as this allows numbers with two decimal places to be represented).
At the points of these curves then instantiate the previously created numbers. By using the index of the points of each spline, and additionally the option Pick Instance as well as Instance Index you can then pick the desired number.

This could look something like this:

Useful note: In case you are wondering why this works when I use a float value as Instance Index: Funnily enough, when using the Instance on Points node, the float value is not rounded up or down, but always rounded down, so all decimal places are truncated.
(Blender 3.4+)

Update 1
...and here is a further development of this approach, which can also handle different and multi-digit numerical values (currently no negative values though).
I'm working on it, but I thought it would be good to share this variant:

(Blender 3.4+)

Great solution to instance the digits 0-9! Good to see there is actually a fully automatic solution.
Btw: Nice trick, doing 'text formatting' with a curve line... I bet this will come in handy sooner or later :-)

I found a decent solution, or let's call it a workaround :

It is based on the Animation Nodes addon :
It creates a collection of 100 texts : 0.0  ; 0.1 ; 0.2 ;   ...    10.0.
The collection is named : "Animation Nodes Object Container"  (sorry not very self explanatory ...)

Then in Geonodes, we calculate the which text must be displayed, in fact, its index. Off course the collection of texts are well ordered and index order corresponds to number order !
Here is this calculus :
My scales vary from 0 to 1.5. I want to map this interval to my set of indexes : [ 0 ; 1 ; 2 ... 99 ].

As you guess, I haven't invented anything here myself. Sources :
Animation nodes

In fact, this can be used to display many kinds of values. So I think that the title of this post is too restrictive. Is there a way to change it to : Geonode : "Display varying values as texts" ?  ... or too any better title you could suggest ?

"I would like to share the .blend with this nice logo but how ??"
See here: https://blend-exchange.com/

Thanks lars ! Now my .blend is available ( although it is not so interesting compared to the others ...)

Oh, I wouldn't say that. I think we all learned something while exploring your issue. And later, hopefully, others can profit from the variety of solutions here :-)

There is actually some way to do this in GN, but it only works for a limited number of objects, since you have to manually connect a sub-group for every instance. It's still more flexible than typing numbers by hand (especially when these numbers are changing dynamically):

The trick is to extract from the Random Value's field data a single value via Sample Index Node, convert it into a string and join the digits (and letters) together into one 'dimension instance'. Don't forget to check Pick Instance in the Instance on Points node.
This is how it looks inside the 'Sampler' group:

I know, it's a bit clumsy. But afaik, it's the closest we can get for now.
Here's the file for reference:

Thanks again Lars, good idea ! My problem is that there is many more fish in this project than can be seen in my screenshot. So I am going to try something else. One option is Python script instead of geonodes that may not be quite mature yet ...


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How to Avoid/Correct Circular Dependencies on IK Rigs with Drivers?
In reference to this report on mis-behaving IK rigs--
https://developer.blender.org/T76158
The answer is, IK rigs with dependency cycles have undefined (glitchy) behavior.
My follow up questions are:
1: How are these dependencies created?
It can't be just from creating a simple IK rig.  Is it created by complex IK rigs such as the 'overlapping/cascading' ik controls as shown here: https://www.youtube.com/watch?v=p0htATi5tpA  ?
Is it created by creating drivers for my IK controls?  Is it created by placing the controls for the drivers on a bone that is the antecedent of the bones with IK constraints on them?
2:  How can I remove/fix them?!
FILE 282+ only (if you can't get it from the developer page)
https://pasteall.org/media/5/2/52b156a866b10f79670d4d4c8f4c1862.blend
Construction:
The horse front and hind limbs have IK chains of 5 joints each.  They are using ITaSC solvers.
Each Leg has an IK toggle switch, located on the COG bone (the root of the movable skeleton, but child of the origin bone).  These are keyframable, so IK can be turned on and off during an animation.
In addition, there is a switch to turn off/on "Snap IK to FK rig," which activates the IK control bones' constraints to copy the loc/rot of their respective hoof bones.  This is inactive, and only used when the IK controls are off, to snap the IK bones back into place when the animation is ready to keyframe the IK back on.
This is certainly a circular dependency, but one that I believe is a 'false' dependency, because it is not active.  Maybe.
Oh... there are also targetless IK chains that can be used to move the whole limb by dragging its descendents.  I don't use those, i could delete them...
Okay, I just saved the file with all those deleted, and i got TWELVE dependency cycles detected instead of 10.  I cannot explain those results.
Anyway, this is what the 282 console tells me about the dependencies...  I have no clue what the heck it is talking about :/
What is an 'IK Chain Overlap'?
Blender Console Info:   (is there a spoiler tag?  this is so spammy.  oh, it doesn't actually fold it up.  sorry.)

  Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Target Front
 R/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Target Front
 R/BONE_READY() via 'Ready ->! Done'   OB_HorseMainRig/IK Target Front
 R/BONE_CONSTRAINTS() via 'Constraints ->! Ready '
 OB_HorseMainRig/ElbowRight/BONE_DONE() via 'Copy Location'
 OB_HorseMainRig/CollarRight/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Torso/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver'

 Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Front
 R/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Front R/BONE_READY() via
 'Ready ->! Done'   OB_HorseMainRig/IK Front R/BONE_CONSTRAINTS() via
 'Constraints ->! Ready'   OB_HorseMainRig/HandMiddle1Right/BONE_DONE()
 via 'Copy Rotation'   OB_HorseMainRig/HandMiddle1Right/BONE_READY()
 via 'Ready ->! Done'
 OB_HorseMainRig/HandMiddle1Right/BONE_CONSTRAINTS() via 'Constraints
 ->! Ready'

   OB_HorseMainRig/HandMiddle1Right/BONE_POSE_PARENT() via 'Pose ->
 Constraints S tack'   OB_HorseMainRig/HandMiddle0Right/BONE_DONE() via
 'Parent Bone ->! Child Bone'
 OB_HorseMainRig/HandMiddle0Right/BONE_READY() via 'Ready ->! Done'
 OB_HorseMainRig/HandMiddle0Right/BONE_POSE_PARENT() via 'Pose ->
 Ready'   OB_HorseMainRig/WristRight/BONE_DONE() via 'Parent Bone ->
 Child Bone'   OB_HorseMainRig/CollarRight/POSE_IK_SOLVER() via 'IK
 Solver Result'   OB_HorseMainRig/Torso/BONE_DONE() via 'IK Chain
 Overlap'   OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver'

 Dependency cycle detected:
 OB_HorseMainRig/HandMiddle1Right/BONE_CONSTRAINTS() depends on
 OB_HorseMainRig/IK Front R/BONE_DONE() via 'Copy Rotation'
 OB_HorseMainRig/IK Front R/BONE_READY() via 'Ready ->! Done'
 OB_HorseMainRig/IK Front R/BONE_CONSTRAINTS() via 'Constraints ->
 Ready'   OB_HorseMainRig/HandMiddle1Right/BONE_DONE() via 'Copy
 Rotation'   OB_HorseMainRig/HandMiddle1Right/BONE_READY() via 'Ready
 ->! Done'   OB_HorseMainRig/HandMiddle1Right/BONE_CONSTRAINTS() via 'Constraints ->! Ready'

 Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Target Front
 L/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Target Front
 L/BONE_READY() via 'Ready ->! Done'   OB_HorseMainRig/IK Target Front
 L/BONE_CONSTRAINTS() via 'Constraints ->! Ready '
 OB_HorseMainRig/ElbowLeft/BONE_DONE() via 'Copy Location'
 OB_HorseMainRig/CollarLeft/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Torso/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver'

 Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Front
 L/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Front L/BONE_READY() via
 'Ready ->! Done'   OB_HorseMainRig/IK Front L/BONE_CONSTRAINTS() via
 'Constraints ->! Ready'   OB_HorseMainRig/HandMiddle1Left/BONE_DONE()
 via 'Copy Rotation'   OB_HorseMainRig/HandMiddle1Left/BONE_READY() via
 'Ready ->! Done'   OB_HorseMainRig/HandMiddle1Left/BONE_CONSTRAINTS()
 via 'Constraints ->! Ready'
 OB_HorseMainRig/HandMiddle1Left/BONE_POSE_PARENT() via 'Pose ->
 Constraints St ack'   OB_HorseMainRig/HandMiddle0Left/BONE_DONE() via
 'Parent Bone ->! Child Bone'
 OB_HorseMainRig/HandMiddle0Left/BONE_READY() via 'Ready ->! Done'
 OB_HorseMainRig/HandMiddle0Left/BONE_POSE_PARENT() via 'Pose ->! Ready'
 OB_HorseMainRig/WristLeft/BONE_DONE() via 'Parent Bone ->! Child Bone'
 OB_HorseMainRig/CollarLeft/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Torso/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver' Dependency cycle detected:
 OB_HorseMainRig/HandMiddle1Left/BONE_CONSTRAINTS() depends on
 OB_HorseMainRig/IK Front L/BONE_DONE() via 'Copy Rotation'
 OB_HorseMainRig/IK Front L/BONE_READY() via 'Ready ->! Done'
 OB_HorseMainRig/IK Front L/BONE_CONSTRAINTS() via 'Constraints ->
 Ready'   OB_HorseMainRig/HandMiddle1Left/BONE_DONE() via 'Copy
 Rotation'   OB_HorseMainRig/HandMiddle1Left/BONE_READY() via 'Ready ->
 Done'   OB_HorseMainRig/HandMiddle1Left/BONE_CONSTRAINTS() via
 'Constraints ->! Ready'

 Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Target Hind
 L/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Target Hind L/BONE_READY()
 via 'Ready ->! Done'   OB_HorseMainRig/IK Target Hind
 L/BONE_CONSTRAINTS() via 'Constraints ->! Ready'

   OB_HorseMainRig/AnkleLeft/BONE_DONE() via 'Copy Location'
 OB_HorseMainRig/KneeLeft/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/HipLeft/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/HipLeft/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/PelvisInv/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/PelvisInv/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/COG/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver'

 Dependency cycle detected:   OB_HorseMainRig/Pose
 Component/POSE_INIT_IK() depends on   OB_HorseMainRig/IK Target Hind
 R/BONE_DONE() via 'IK'   OB_HorseMainRig/IK Target Hind R/BONE_READY()
 via 'Ready ->! Done'   OB_HorseMainRig/IK Target Hind
 R/BONE_CONSTRAINTS() via 'Constraints ->! Ready'

   OB_HorseMainRig/AnkleRight/BONE_DONE() via 'Copy Location'
 OB_HorseMainRig/HipRight/POSE_IK_SOLVER() via 'IK Solver Result'
 OB_HorseMainRig/PelvisInv/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/PelvisInv/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/COG/BONE_DONE() via 'IK Chain Overlap'
 OB_HorseMainRig/COG/POSE_IK_SOLVER() via 'IK Chain Result'
 OB_HorseMainRig/Pose Component/POSE_INIT_IK() via 'Init IK ->! IK
 Solver'

 Dependency cycle detected:
 OB_HorseMainRig/ToeLeft/BONE_CONSTRAINTS() depends on
 OB_HorseMainRig/IK Hind L/BONE_READY() via 'Copy Rotation'
 OB_HorseMainRig/IK Hind L/BONE_CONSTRAINTS() via 'Constraints ->
 Ready'   OB_HorseMainRig/ToeLeft/BONE_READY() via 'Copy Rotation'
 OB_HorseMainRig/ToeLeft/BONE_CONSTRAINTS() via 'Constraints ->! Ready'
 Dependency cycle detected:
 OB_HorseMainRig/ToeRight/BONE_CONSTRAINTS() depends on
 OB_HorseMainRig/IK Hind R/BONE_READY() via 'Copy Rotation'
 OB_HorseMainRig/IK Hind R/BONE_CONSTRAINTS() via 'Constraints ->
 Ready'   OB_HorseMainRig/ToeRight/BONE_READY() via 'Copy Rotation'
 OB_HorseMainRig/ToeRight/BONE_CONSTRAINTS() via 'Constraints ->! Ready'

 Detected 10 dependency cycles

TESTING:
i'm using 2.79, as it has readable console messages.  following standard ik creation instructions.
1: extrude ik target and ik pole.  no circular dependencies.
2: set parent of target/pole to root bone.  no circular dependencies.
3: add ik constraint to the limb, chain length 2.  Circular Dependency Created!
Dependency cycle detected:
IK.Target.Leg.L depends on Origin through Parent Relation.
Origin depends on IK.Target.Leg.L through IK Constraint.
how is my origin (the root bone in this rig) dependent on the leg ik target, when the ik chain doesn't even come anywhere near it?
what should i be setting the ik target parent to, if it isn't the root bone?

When you first add an IK constraint to a bone chain, the chain will include ALL the bones right back to your root bone. If your control bone or pole target are parented to the armature at this point you will have a cyclic dependency, which cannot be resolved. The code calculation fails and the armature is then broken.
If you set up the IK constraint first, shortening the chain to only the bones you want the IK to affect, and only then parent the controller or pole target to the root bone, the cyclic dependency doesn't happen. There is a "gap" between the last IK bone and the root bone.
The same is true (with a proviso) of any constraint you have added to a bone chain to "connect" a non connected bone. The moment you add an IK constraint to it you will get a cyclic dependency.
Dependency is directional. The child of another bone or object depends on it's parent. But the parent does not depend on the child. Similarly, every relational constraint has a "source" bone or object and an "owner" bone or object. The behaviour of the "owner" bone (which is the one that has the constraint applied to it) depends on the behaviour of the "source" bone or object.
If you imagine an arrow representing the direction of dependency, so that the information from the base of the arrow affects the object the arrow is pointing at, then any constraint that does not violate this directionality with regard to other constraints on the same armature will not create a cyclic dependency.
The same is true of drivers and actions that create relationships between objects. If you add a driver on a parent object that takes values from it's child object, you will have a cyclic dependency which will fail.

I think I have figured it out.
If you create the IK Target/Pole and parent them to the Root before you create the IK control, it doesn't work.
If you clear the IK Target/Pole parent, then set up the IK constraints, then parent the Target to the Root, it's fine.
Proper Steps:

Extrude/Create your IK control bones.
Clear their Parents.
Set up the IK constraints on your rig.
Set the actual Parents of your IK control bones.


text:
Python- Panel and Redo Panel Hooks and Method
i'm using  2.83.4
and if someone could point me to a tutorial on hooking controls from a panel and how to get the redo panel to work right, that would help immensely!
HalfKill is basically the same as the native blender Symmetrize command, but i want to have the option to not remove the mirror modifier at the end.
i have three parameters for it:
x_pos tells it to delete the left side or the right side
do_mir tells it to add a mirror modifier (in case i just wanted to delete a side)
app_mir tells it to apply the mirror modifier, like symmetrize
my problems:
A: checkboxes for these parameters do NOT appear in the panel, although i have created them there.
B: those checkboxes DO appear in the redo panel, but when i toggle them, only the first change has any affect
also when i change the checkboxes i get this in the info:
bpy.data.window_managers["WinMan"].(null) = True
i... have no idea what that is trying to tell me.
** i have figured this out:  when i turn a checkbox on, the winman null is True, and when i turn a checkbox off, the winman null is False. so... it's telling SOMETHING that i'm checking/unchecking things.  (how it knows what things, i don't know.)
code:  i have updated the code to have both operators and the panel in one script.  oh, let me take out 'mirror and split' because that is simple and works fine...
## Select faces on the Right (X neg) half of the model, and delete them.
## Also, add a Mirror Modifier, if desired.  And apply it, if desired.

import bpy
import bmesh

################ HALF KILL
class HalfKill(bpy.types.Operator):
    """Delete half the mesh, add Mirror Modifer"""
    bl_idname = "object.half_kill"
    bl_label = "Half Kill"
    bl_options = { 'REGISTER', 'UNDO'}

    ## need some properties (variables) for the panel switches
# https://blender.stackexchange.com/questions/159321/give-a-variable-to-an-operator

    x_pos : bpy.props.BoolProperty(name="Delete Left",
                                   description="Remove X+ side or X-",
                                   default = False) ##if TRUE, delete X POS side
    do_mir : bpy.props.BoolProperty(name="Add Mirror",
                                    description="Add Mirror Modifier",
                                    default=True) ##if TRUE, add the mirror mod
    app_mir: bpy.props.BoolProperty(name="Apply Mirror",
                                    description="Apply Mirror when done",
                                    default=False ) ##if TRUE, apply the mirror mod

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    def execute(self, context):
        print('executing')
## Error 1: is object selected?
        ob = context.active_object
        if not (ob.select_get()):
            self.report({'WARNING'}, "No Object Selected.")
            return {'CANCELLED'}

        ## Error 2: is there already a mirror on it?
        if (any([m for m in bpy.context.object.modifiers if m.type == "Mirror"])):
            self.report({'WARNING'}, "Object already has Mirror Modifier.")
            return {'CANCELLED'}

        ## reference the properties with a variable
        xpos = self.x_pos
        domir = self.do_mir
        appmir = self.app_mir

        ## Grab the Middle Line
        bpy.ops.object.mode_set(mode = 'EDIT', toggle = False)
        bpy.ops.mesh.select_all(action = 'DESELECT')

        ## use bmesh to access select history and manipulate object
        mesh = ob.data
        bm = bmesh.from_edit_mesh(mesh)

        ## Select Middle Vert
        bpy.ops.mesh.select_mode(type = 'VERT')

        vtest = False ##check for center vertex
        for vert in bm.verts:
            if(vert.co[0] == 0):  #coordinate 0 (x) is zero (center)
                vert.select = True
                ## to make it active, you need to add it to sel history in bmesh
                bm.select_history.add(vert)
                vtest = True
                break

        if(vtest): ##we found a center vert!
            # select side of ative, based on x_pos
            if(self.x_pos):
                bpy.ops.mesh.select_axis(sign='POS')
            else:
                bpy.ops.mesh.select_axis(sign='NEG')
            ## switch to face mode and delete; don't forget to flush :X
            bm.select_mode = {'VERT', 'EDGE', 'FACE'}
            bm.select_flush_mode()
            # activate face select mode
            context.tool_settings.mesh_select_mode = (False, False, True)
            # Delete
            bpy.ops.mesh.delete(type='FACE')

        else:
            print("no centerline found, using bisect")
            # No Center, make one!  use Bisect
            # need to select all first
            for vert in bm.verts:
                vert.select = True
            # co = position, it is global, not local. no(rmals) 1,0,0 = face X+
            ## clear_inner=True (delete X- side)  clear_outer=True (delete X+ side)
            ## USING BOTH AT ONCE CANCELS IT!
            ## start and end x/y are...??? wtf??? default = -inf:inf
            if(xpos):
                print('clear inner')
                bpy.ops.mesh.bisect(plane_co=(0, 0, 0), plane_no=(1, 0, 0),  clear_inner=True) #,threshold=0.0001) ##, xstart=463, xend=462, ystart=144, yend=509)
            else:
                print('clear outer')
                bpy.ops.mesh.bisect(plane_co=(0, 0, 0), plane_no=(1, 0, 0),  clear_outer=True)
            print("well, did it bisect?")
            ## i think you need to update the thing? :/

            # self.report('WARNING', "No centerline found.")
            # return {'CANCELLED'}

        ## go to object mode, cuz staying in edit looks funny
        bpy.ops.object.mode_set(mode='OBJECT')

        ## in this part, i determine if the Mirror toggle is on?
        #test = self.do_mir
        if(domir):
            print("doing mirror")
            bpy.ops.object.modifier_add(type='MIRROR')

        ## and, determine if you apply it
        #test = self.app_mir
        if(appmir):
            print("applying mirror")
            bpy.ops.object.modifier_apply(apply_as='DATA', modifier="Mirror")

        #bm.to_mesh(mesh)
        #bm.update()

    ## that should do it
        print('finished')
        return {'FINISHED'}

    def invoke(self, context, param):
        #darkfall's floating panel
        return context.window_manager.invoke_props_dialog(self)

########################### PANEL
class MirrorAndSplitPanel(bpy.types.Panel):
    """Split Mirror & HalfKill"""
    bl_label = "Mirror Ops"  ##on the section header
    bl_idname = "OBJECT_PT_mirror_and_split"  ##ui name for it
## ^^set automatically if not defined here.^^
    bl_space_type = 'VIEW_3D'  ##Where
    bl_region_type = 'UI'  ##what shelf
#[‘WINDOW’, ‘HEADER’, ‘CHANNELS’, ‘TEMPORARY’, ‘UI’, ‘TOOLS’, ‘TOOL_PROPS’, ‘PREVIEW’, ‘HUD’, ‘NAVIGATION_BAR’, ‘EXECUTE’, ‘FOOTER’, ‘TOOL_HEADER’], default ‘WINDOW’
    bl_category = "Edit"  ##Name of Tab
    #bl_context = "objectmode" or "mesh_mode" ## what mode, objectmode or mesh_mode or...?
    bl_options = {"DEFAULT_CLOSED"}

    @classmethod
    def poll(self,context):
        test = False
        if context.mode in {"EDIT_MESH", "OBJECT"}:
            test = True
        if context.object is not None:
            test = True
        return test
        #return (context.mode in {"EDIT_MESH", "OBJECT"})
    #        return (context.mode in {'EDIT_MESH','OBJECT'}) or (context.object is not None)

    def draw(self, context):
        layout = self.layout  ## create a layout for yourself
        #scene = context.scene ## dunno, but checkbox examples use it
        #mytool = scene.mytool ## no idea, but checkboxes need it
        # it causes the buttons to not appear

        #obj = context.object  ## what the function is operating on: object --not yet!

        #row = layout.row()
        #row.label(text= bl_label, icon = 'MODIFIERS')

        row = layout.row()
        row.operator("object.mirror_and_split")
        row = layout.row()
        row.operator("object.half_kill")
        #sub row
        #sub = row.row()
        # layout.prop(mytool, "my_bool", text="Bool Property")
        ## where mytool = scene.mytool :X
        ##    & parameter names are in quotes

        ##Darkfall doesn't 'draw' these... they appear automatically???
        #row=layout.row()
        #what is difference between layout.prop and row.prop? neither work
        #row.prop(obj, "x_pos", text="Remove X+ Side")
        #row.prop(obj, "do_mir", text="Add Mirror")
        #row.prop(obj, "app_mir", text="Apply Mirror")
        ## why do these only appear on redo panel?  cuz undo is on?

        layout.separator()  ## small blank 'whitespace'

########################## REGISTER

def register():
    bpy.utils.register_class(Mirror_and_Split)
    bpy.utils.register_class(HalfKill)
    bpy.utils.register_class(MirrorAndSplitPanel)

def unregister():
    bpy.utils.unregister_class(Mirror_and_Split)
    bpy.utils.unregister_class(HalfKill)
    bpy.utils.unregister_class(MirrorAndSplitPanel)

if __name__ == "__main__":
    register()

PS: if you post example codes, could you please comment it.  i'm REALLY new at this and especially python/OOP, and if it's not clear where something came from, i'm lost.  thanks!

okay, i converted this back to a 2.79 script, and it works flawlessly.  the redo panel shows up, the checkboxes activate/deactivate the functions properly in real-time...  i'm astounded.
what am i doing wrong for 2.8+?


text:
Copy Bone Rotation Constraints Between Armatures with Different Initial Bone Angles
i have three horse rigs that are all built slightly differently.  i want to create one master rig to animate them all :X

left: Rig1  center: Master Rig  right: Rig2
the problem is, no matter which space to which space i choose, something screws up.
it seems a no-brainer that 'pose space' to 'pose space' means 'if the master bone is set to 0 rotation, then set the constrained bone to 0 rotation.'
however, the constrained bones point straight down, NOT at their zero rotation (which is at an angle in their respective rigs.)
the pose actually LOOKS okay, from the side, but it is not.   Rig1, for example, has the thigh bone angled out, while the master rig has it straight up and down.

you can see in this pose, that Rig1 on the left has its knee crunching into its torso.
i can fix this by changing to local space.  UNLESS i then want to rotate the rig by the pelvis.

this is the same pose as above, but with the hip rotated.  (Rig2, right, is still using pose space to pose space, so at least it doesn't start pointing an entirely different direction.)
yes, the screenshots are in blender 279, but i opened this file in 360, and none of the options in those constraints gave me any different (usable) results.
HOW can i tell these bones to just.... copy the rotation of the bone i point them to?  is this going to involve scripts and stuff??  i'll need to keyframe everything, too.  shouldn't the bone constraint be able to handle this type of situation?
HELP!
IN ADDITION.... (yes, i want the world).  some of the bones axes don't match.  i got my horizontal hip control to map to the vertical controls on these rigs.  but Rig1, for example, the hoof bone there is 'backwards' compared to the master rig.  i tried using invert on an/all X/Y/Z axes, but no combination thereof, nor offset (with Y at 180) was able to un-twist it.
in this particular instance, i think i might have to add a 'mediator' bone to Rig1, that will read the Master bone constraint, and then the Rig1 bone will be constrained to that in a different manner that will face it right way 'round.
...but i can't do that with every single bone in all the rigs :/  (in a timely manner!)
i can't possibly be the first person who's wanted to do something like this??  it SHOULD be workable... i hope!?

Please [edit] your question to correctly insert your images to your post so that we can see them. You can copy your image where you posted them, then paste them here : they should be automatically uploaded and inserted as they should be.

oh, apologies.  i didn't notice the image button.
however, it isn't accepting the lightshot urls.  and neither is imagur.  i will look for an alternate solution.

It will be probably best to upload your file on Blend-Exchange and [edit] your post to add the link, so that we can check the whole rig and see how it works. Also, have you considered that instead of trying to make different rigs match each other, it would be simpler to just animate one rig, then copy the animation to the others and do the little adaptations they might need? That's how we retarget animations usually. I doubt the rig system you are wishing for will make it so you don't need to adjust the animations for each rigs anyway.

If what you need is the bone copying the rotation of its target but ignoring the rotation inherited from the target's parent, use Local Space:

If you want to copy the rotation with the parent's inherited rotation but ignore the armature object's rotation, use Pose Space:

If you want the above but that also takes the armature object's rotation, use World Space:

these are good explanations and examples.
...
yet, in image 1, i'm using pose space to pose space.  and when the master bone is at zero rotation, the constrained bones are at some rotation to match the world angle of that bone.
...
and in image 3, if i use local space, rotating the master root bone (which rotates the constrained root bones) causes the child bone to point in a totally different direction.

what do i use, both 'from' and 'to',  to get every bone in the constrained rigs to match the actual rotation of its corresponding bone in the master rig? not the 'where it looks like it is pointing' (straight down in image one), but where it is actually rotated (zero rotation).


text:
Geometry Nodes Flower Grow - Can't get rotational control of the leaves and petals
I've watched a bunch of Geo flower tutorials and read a lot of articles, but I haven't been able to figure out how to better place and control leaves or petals at the tops of the flower stems.
I'm betting that this is a simple case of me not knowing what fields to use.
I start with a base geometry:

Then I create seeds / distribute points on faces:

Then create the stems:

Now Adding flowers is where everything collapses:
This image is one attempt. The leaves rotate correctly and they are at the top of each stem, but as you can see, they are all identical and I can't figure out how to randomize them. If I randomize this it makes them all exactly the same random amounts.To be clear, I want to randomize the X and Y of the flower petals so they aren't all exactly rotated and look the same.
(I'm using the output of the Stem's Trim Curve node to a Resample Curve node, to bring the points over) (perhaps that is a mistake?)

So I tried a different way. The leaves here are rotated correctly, but they run down the length of the stem instead of around the top point of the stem. If I try an Endpoint I get only one leaf at the top.

I know it's some simple math or something but for the life of me I can't get it right. Any assistance would be greatly appreciated.

I am pretty sure that you are looking for a setup of this kind:
(Simplified setup)
If I understand correctly, you've actually solved most of the task already, it's just that you haven't managed to rotate the petals for the individual flowers yet.
The trick here is, after instantiating the circles where you create the petals, to capture their index.
You do this with Capture Attribute in the domain Instance. This way you have a unique index per instance, and can use this value additionally to calculate the rotation of the petals.
In this example I simply used the node Random Value for this and used the previously captured index as ID.
I then add this randomly generated value here with the rotation of the petals along a circle.
With Vector Rotate and Align Euler to Vector I then create the corresponding Rotation for the individual instances.
(Blender 3.2)

Update
You can, of course, add more random angles by adding different angles to the rotation. Note that these values are in radians, not degrees.
Because of this setup, each individual point at which a petal is created has a unique index and does not represent instances, so too is the rotation created for each petal unique.

Hello! Thanks so much for your reply.  but I think I didn't specify the randomness I was looking for.. I don't need to rotate on the Z axis randomly.. because you can't tell the difference.. the flowers still look exactly the same.. what I'm looking for is a randomness to the X and Y so all the flowers have randomness. I tried to figure that out, but I don't really understand your Geo flow.. Do I need an entirely different set up to do such a thing?? @quellenform

@GorkEnterprises You would actually only have to extend this setup a little. I have changed the answer accordingly. You would just have to add additional values for the angles, and each petal would get a unique rotation. And yes, you would actually have to build the setup differently, since instances are not changeable afterwards (apart from the transformation of the mesh). Instance == Duplicate of an object.

Again, thank you for the update.. However, again, I don't think this is working.. it seems to be exactly the same random on every flower, but just a random Z rotation, which makes it seem like every flower petal is rotated randomly, but on closer inspection the flowers have identical randomness in the X and Y, but still only Z is actually random. it's even apparent in the image you uploaded.. the flowers are identical in the X and Y, but just randomly rotated on Z. You did mention that the setup would have to be build differently..? I've been trying to modify your set up, but to no avail.

@GorkEnterprises Download my example file and add another node Random Value as seen in my update. If you do it this way, you will notice that each petal gets a unique rotation on each axis. You can check it here: https://i.sstatic.net/kaVZZ.jpg

I think I was using the random node as Float instead of Vector. I think it's working now. Thanks for the assistance. Now to the task of animating it all.. oh boy.. we may speak again.. :-)


text:
Bone's constraint limit X axis rotation more than 180° doesn't work
I have a bone that I want the rotation around its own X axis limited to 220°.
I have checked "limit X", and set "min" to 0°, and "max" to 220°. Also set "convert" to "Local space".
When I rotate the bone, it is well limited as intended around its X axis, but beyond 180° it returns (jump) to the 0° position, until I rotate beyond 360° where it starts to rotate again.
How to allow the limitation to go beyond 180° ? What am I missing ?
Note : I tried different "rotation orders" (XYZ, Quaternion...) but nothing changed. And also tried to check "For Transform" in the constraint panel with no more luck.

The values for the Rotation Limit Constraint are clamped 180 to -180. This is a known limitation. An example:

As soon as i try to rotate the bone beyond 180° the bone snaps back to 0°
You can find more about this in the Blender manual about Limit Rotation.
Note: There is a small chance that this limitation will be released some time in the future. You can find more about that in the bf-animsys mailing list.

Ok, thanks a lot for your time of research. I'll wait for this to be fixed... And in the meanwhile I won't limit the rotation at all :)

I found that using Local Space instead of World Space can be used to work around this limitation... provided that the bones are set up to facilitate that.

If possible consider using the values -40 (minus) to 180 to get 220 degrees of rotation.
Perhaps adding another bone may help to build up rotation in the style that suits you.
The values are clamped 180 to -180 if I read this documentation correctly.
I get the same interaction as you explained.
Here is a technical link
http://www.blender.org/documentation/245PythonDoc/Constraint-module.html

Thanks. But, in the doc you linked, I read : "Used by Limit Rotation (LIMITROT) constraint: (...) XMAX (float): clamped to [-360.0,360.0]". And using -40° here doesn't help, because I have to limit also at 0° for "min" value...

fyi: I have started a thread in the bf-animsys mailing list about that: http://lists.blender.org/pipermail/bf-animsys/2014-September/000159.html

@GaiaClary Thanks for adding that clarity to the situation


text:
Is there a way to introduce a random size for children particles?
When I create a particle system using object or group rendering I often want to make the particles' sizes slightly randomized.  I accomplish this by changing the random size spinner under physics.

Here is an example:

But then, to save memory and add more particles, I usually use interpolated children particles.

But using children particles seems to ignore the random size spinner.

The particles are now all the same size.  The value of the aforementioned random size no longer has any impact whatsoever on the look of the particles; and nothing I could find under the children settings has a similar effect to it.  All the random values on the children rollout just seem to change the location and/or rotation in some way or another, not the size.
So how can I change the random size of the children particles?
Edit:
In response to Bithur's comment, this is what I get when I adjust the length and threshold settings:

As you can see, half of the particles are the normal height and half are scaled down a specific amount.  It's slightly better, but by no means a random scale.

play with length and threshold of children. Parents are not viewed by default.

In Simple mode there is an option under Size that says Random, so if you don't need to use Interpolated mode then that should work.

@NoviceInDisguise Unfortunately most of the time I need to use interpolated.

I tried it with just one particle, and all of the interpolated ones were different heights. I can't figure out why :/

@Bithur I tried that and it seems to just scale down half the particles to an exact amount.  See edit...

I have found what appears to be a solution, however it might be a bug/unexpected (or unsupported) behavior. What you do is you pretend you are going to use the Simple mode, set the random size, and then switch back to Interpolated mode. Some reason the random size data is "remembered" and now the particles are random sizes.

This appears to render correctly, and changing other particle settings doesn't appear to affect it at all.

My hero! :) thx for this tip!

Wow, that is weird, thanks a ton!  Now if someone can figure out why that spinner is missing from the interpolated settings...

Hear hear! Seems like a very logical addition.


text:
What does the mapping type do on a mapping node?
What do the four buttons (texture, point, vector, and normal) at the top of the mapping node do?  It by default uses point and I have never changed it.  But in the answer to this question David mentioned changing it to texture (which makes intuitive sense).  But technically what do these buttons do?  I have always thought the mapping node is the same as using a vector > split XYZ and math nodes to manipulate the components, in fact I often do this instead of a mapping node if I want to plug some other nodes into the values.

The mapping node works by changing the coordinate system. This is why (when left on the default point setting) you have to put in a larger number to scale a image down. What is you are actually doing is scaling the texture coordinates up.
When set to Texture you are still changing the Coordinate system, not the texture. The only difference between Point and Texture is that for texture all the values are inverted.
Try it, when set to point a value of 2 is required to make the texture repeat 4 times.
When set to texture to get the same repeating 4 times the value must be .5.
I would highly recommend going through the cg cookie tutorial (archive) about the mapping node.

Thanks, that cg cookie series is amazing!  But for completeness could you add explanations of the vector and normal buttons?

@PGmath The only information I could find about the other two options Vector and Normal are these few lines.
""Vector Transform a direction vector.
Normal Transform a normal vector with unit length.""  I have never used either of those 2, and I could not find out much about them.

Strange, I will try to find some time to do some experimentation and see if I can figure out the difference.  Thanks again!

@PGmath I spent about an hour, and still can now write what those two do.

@cegaton I think we are saying the same thing, a value of 2 in both fields (the entire answer talks about repeating in both directions) will make the texture repeat a total of 4 times.

I know this is an old question, but maybe someone still finds useful what I found. The tooltips actually explain the difference:

Texture: Transform a texture by inverse mapping the texture coordinate
Point: Transform a point
Vector: Transform a direction vector
Normal: Transform a normal vector with unit length

If you want to understand it deeper, like I did, this might not be enough for you. I looked in the Blender source code, and I found the following comments:

Texture: to transform a texture, the inverse transform needs to be applied to the texture coordinate
Point: forward transform
Vector: no translation for vectors
Normal: no translation for normals, and inverse transpose

What does all this mean? Direction and normal vectors should not be translated because they represent a direction, and normal vectors should be transformed with "inverse transpose"
At this point you might ask (as I did...): "Hey, isn't the Vector mode redundant if all it does is that it ignores my Location values?". The answer is that the calculations are faster if one knows in advance that there is no translation. A different, faster code is called inside Blender. So yes, Vector has the same result as Point with 0, 0, 0 Location, but it is calculated faster.

So how should you use this node? For texture transformations you can use either the texture or the point as David explained in his answer. If you are an advanced user and you want to transform direction or normal vectors, use the corresponding options, and don't be surprised when the Location values are ignored.


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Motion blur not applying to rigged propeller
For one of my projects I have a propeller rigged with an armature.  I have animated it to spin for the express purpose of getting motion blur on it (I am just rendering a still image).  However when I turn on motion blur in the render settings (shutter = 1.00) the propeller is not blurred.
Here is a simplified example scene and render.  Note the example box and cross are blurred properly but the propeller is crisp.

Thinking is was because the propeller is animated from an armature I tested a different armature-animated object but it blurs fine.

Why is the propeller not being blurred?

I can't be quite certain WHY, but Cycles isn't properly understanding the mesh distortion that your armature is doing. When I separated the moving parts of the rotor from the mast into two separate objects, and then animated the rotor object instead of the armature, the rotors blurred properly:

I suspect the armature isn't what's causing the problem, rather that it's the mesh distortion. Here's why: I also tried animating a shape-key instead of using the armature (with the whole mesh as one object), and Cycles did the same thing you're seeing. So, it must have something to do with Cycles not properly blurring meshes when they are deformed, instead of TRANSformed (LocRotScale). Even turning on "Deformation" in the motion blur settings for the mesh didn't change anything.
I suspect that you can still use the armature, so long as the moving components are a separate object from the non-moving components (or from components that move differently). I'd wager that your test rotor was also a separate object from the two cubes below it, and that's why it blurred properly.
This MIGHT be a bug. I'd recommend looking in the forums to see if it's been discovered. In the mean-time, it's somewhat more conventional to separate a mesh by moving parts, anyway ;-)
I hope that helps!

Thanks a ton!  I'll accept your answer as soon as I can get to my other computer and test it.  The strange thing is the second test I performed (3rd and 4th pics) works fine with blurring deformation.  I suspect it is a bug, I'll try to get around to looking for it and reporting it over the weekend.

It seems that this problem was caused by having Auto Smooth enabled under the Object Data properties panel > Normals rollout.  After disabling Auto Smooth and using an Edge Split modifier instead it renders as expected with motion blur.
I have no idea why enabling Auto Smooth interferes with motion blur, I suspect it is a bug.


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Can I get a new random number per ray in the node editor?
In the node editor, I am looking for a way to get a random number (in [0,1)) per ray.  The object info node's random output just gives a random number per object, the number never changes.  I am looking for a way to get a new number every time the shader is sampled.
I am aware of this question, however that is not quite what I am looking for.

Just curious.. What do you want this for?

try combining some ray outputs with some math to produce some thing that seems random. outputs like ray length,view vector and camera_uv coordinates...

@Chebhou  The problem is that I need it to give me a different value every time I sample the shader, even in the same spot.  To get a static random value I could use a noise texture with a huge scale.

@PGmath Oh I see , i don't think there's a variable related to the sample number AFAIK , check if OSL can provide such a thing

@gandalf3  Well, the thing that brought it to mind at the moment was trying to more properly roughen a fake glossy reflection.  (Blurring does work mostly but I was looking for another way.)  But I have wished there was such a feature in the past though for other reasons, mostly having to do with various tricks to speed up render times/reduce noise.

There's enough randomness in the Position from the Geometry node. It will almost never be exactly the same for two samples, but you have to apply a hash function to convert it to a random number in the [0,1) range.
The simplest solution would be to use a Voronoi or Noise Texture node with a very large Scale.
Another solution is to make your own hash function using math nodes, replicating for example this GLSL code.

I think you have to combine as many inputs as possible for Noise texture with big scale: window coordinates, per-object random, object local and global coordinates, normal vector, frame number, etc, to get higher enthropy, and maybe this way you will get something close to what you want.

I don't think this will work, I need a new random number per sample, i.e. every time the surface is sampled a new number is generated.

Ok, I understand. I mean, you have to gather many possible input factors where at least some can change between frames, inside pixel, etc, to get high enough enthropy for one noise texture with pretty big scale, so every ray will meet new value. Also I forget about one more thing: make seed driver-controlled and put random function there to get random rays for every frame and even render launch link. BTW: I tried to use this driver in shader - didn't work.

I'm not quite sure what you mean, but I think I mostly get it.  But I'm not really interested in frames/animation, what I am looking for is something that will give me a new number every time a surface is sampled, within a frame.

BTW, A sample is where cycles shoots a ray from the camera at a pixel and it bounces through the scene to determine what color that pixel should be.

Of course. When you put on surface very fine-grain noise, then every ray will get own random value, combine it with that random-seed driver and all rays became more random every time you render even same single frame.

But, according to my understanding of what you are saying, within a single render of a single frame the same spot on a mesh will always have the same number.  The point of my question is to get a new number each time the same spot on the mesh is sampled within a single render.

BTW, as of 2.75 you don't need to randomize the seed with a driver, there is a button to pick a new seed per frame.  But this doesn't apply to my question as I am not rendering an animation

It's not about animation only, with this driver you will get new random number absolutely for every render launch even for same frame number. But unfortunately this driver don't work with material nodes.


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Multiple addons using the same name
I was trying to install the add-on Blam Master and for any reason was not showing up, and didn't show any action confirming the installation. I try to run it again an this error popped out:
Multiple addons using the same name found!
likely a problem with the script search path.
(see console details)

Looking at the console nothing shows up... Also, I tried to search for the duplicate file in the Program Files folder, and the AppData folder, but there is no duplicate add-on either.
How can I get rid of the warning? Is there a statement I need to execute in the console? I'm using Windows 10 i7 processor

Check the system console https://www.blender.org/manual/interface/window_system/console_window.html , not the python console.  The offenders will be in your addons folders.

I would add @batFINGER link to the answer from cegaton. Very helpful as well.

I had the same error at one point, so I will expand on Cegaton's answer with what the solution was for my case as it may be helpful. The duplicate files may also appear in the addons_contrib folder.