Hair strands do not scale with model #38559

New Issue

Zauber Paracelsus · 2014-02-09T16:17:06+01:00

Zauber Paracelsus commented

2014-02-09 16:17:06 +01:00

System Information
64bit Linux Mint 16, kernel 3.11.0
GeForce GTX 650 Ti, driver version 319.32

Blender Version
Broken: 2.69.0 r60991

Short description of error
When a character model is scaled up or down, the hair strands on the character are not scaled with it. They retain the same size and orientation.

Additional Note
I am using blender to make a fantasy-themed comic, and it will have multiple cases of growth or shrinking spells being used. So, this issue impacts what I'm planning on doing and prevents me from using the hair simulation in place of ugly mesh hair.

Exact steps for others to reproduce the error

Download this file: HairScalingBug.blend
In pose mode, scale the single armature bone. The hair does not increase in size with the emitter mesh
Alt-S to scale back down.
Go into Particle Edit mode on the emitter mesh, and style the hair a bit.
Go back into pose mode with the armature bone. Scale up, and see the hair styling get ruined.

**System Information** 64bit Linux Mint 16, kernel 3.11.0 GeForce GTX 650 Ti, driver version 319.32 **Blender Version** Broken: 2.69.0 r60991 **Short description of error** When a character model is scaled up or down, the hair strands on the character are not scaled with it. They retain the same size and orientation. **Additional Note** I am using blender to make a fantasy-themed comic, and it will have multiple cases of growth or shrinking spells being used. So, this issue impacts what I'm planning on doing and prevents me from using the hair simulation in place of ugly mesh hair. **Exact steps for others to reproduce the error** 1) Download this file: [HairScalingBug.blend](https://archive.blender.org/developer/F76588/HairScalingBug.blend) 2) In pose mode, scale the single armature bone. The hair does not increase in size with the emitter mesh 3) Alt-S to scale back down. 4) Go into Particle Edit mode on the emitter mesh, and style the hair a bit. 5) Go back into pose mode with the armature bone. Scale up, and see the hair styling get ruined.

Zauber Paracelsus commented

2014-02-09 16:17:06 +01:00

Changed status to: 'Open'

Zauber Paracelsus commented

2014-02-09 16:17:06 +01:00

Added subscriber: @ZauberParacelsus

Brecht Van Lommel commented

2014-02-10 14:34:12 +01:00

Changed status from 'Open' to: 'Archived'

Brecht Van Lommel closed this issue

2014-02-10 14:34:12 +01:00

Brecht Van Lommel self-assigned this 2014-02-10 14:34:12 +01:00

Brecht Van Lommel commented

2014-02-10 14:34:12 +01:00

That's by design unfortunately. I think it was a mistake, the particle/hair system has been designed to work in world space, while it really should work in object space. We don't consider that a bug at the moment, it will require a major refactor to fix that.

Zauber Paracelsus commented

2014-02-10 15:07:45 +01:00

Do you have any suggestions for workarounds?

Brecht Van Lommel commented

2014-02-10 15:11:12 +01:00

You could perhaps parent the particle object to another object, then the hairs do scale I think, though for thickness etc. you may need to create a driver as well.

Zauber Paracelsus commented

2014-02-10 15:12:20 +01:00

Yeah, I've tried that already. Doesn't work, sadly.

Zauber Paracelsus commented

2014-11-16 19:29:03 +01:00

Added subscriber: @brecht

Zauber Paracelsus commented

2014-11-16 19:29:03 +01:00

@brecht I figured out a solution to this one. Instead of making the scale driver apply to the armature's root bone, I apply it to the scale of the armature itself. Doing it that way, nothing gets messed up at all.

EDIT: I think what's going on is that hair doesn't get properly affected by scaling with the armature modifier. Whereas if I just scale the armature itself, everything gets scaled through parenting relationships instead.

@brecht I figured out a solution to this one. Instead of making the scale driver apply to the armature's root bone, I apply it to the scale of the armature itself. Doing it that way, nothing gets messed up at all. EDIT: I think what's going on is that hair doesn't get properly affected by scaling with the armature modifier. Whereas if I just scale the armature itself, everything gets scaled through parenting relationships instead.

👍 1

shaun kreider commented

2014-12-13 20:51:39 +01:00

Added subscriber: @ShaunKreider

shaun kreider commented

2014-12-13 20:51:39 +01:00

@ZauberParacelsus thanks for that work-around! This scaling issue has been getting in the way of using multiple characters in one scene that weren't exactly created proportionately to each other.

VKumarV commented

2023-10-03 18:47:20 +02:00

hey, i do have this same issue. When scaling down the armature works, but i want to scale down the root Bone. I tried by adding drivers to root bone to the armature scale, but it doesn't work. But i found one solution, convert the particle system into mesh, after that, convert it into curve and give some thickness, then decimate the hair as now it will be having a heavy number of polygons(something like around 50 Million! But your solution sounds more good and it will keep the polygons never increase, so that will help. It would be great if you can tell me how did you do it?

Thank you

hey, i do have this same issue. When scaling down the armature works, but i want to scale down the root Bone. I tried by adding drivers to root bone to the armature scale, but it doesn't work. But i found one solution, convert the particle system into mesh, after that, convert it into curve and give some thickness, then decimate the hair as now it will be having a heavy number of polygons(something like around 50 Million! But your solution sounds more good and it will keep the polygons never increase, so that will help. It would be great if you can tell me how did you do it? Thank you

shaun kreider commented

2023-10-04 01:03:20 +02:00

That was 9 years ago... but I think my work around was to append the character into a scene and scale everything together in object mode to the needed size before working in pose mode.

VKumarV commented

2023-10-05 12:59:24 +02:00

hey. thank you for your reply, can't we do it any other way? the way it told you is very laggy

shaun kreider commented

2023-10-05 22:29:15 +02:00

Scaling the root bone has the same effect as scaling everything in object mode though. Usually. Can't help you any further I stopped using bender hair years ago.

VKumarV commented

2023-10-06 16:53:14 +02:00

ok, thank you! now everything seems fine! thank you for your help

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Hair strands do not scale with model #38559