How to change the length of a bone?

Development Character & Animation
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1

I’m making a character creator and was wondering if it’s possible to change the length of individual bones in a rig? For example, if the player wanted a tall character with short arms, would it be possible to manipulate a rig with average proportions in realtime?
I’m proficient in Blueprint but haven’t plumbed the depths of animation/rigging yet, so I’m unsure what search terms to use to find the info I need. Any help would be much appreciated!

Edit: Important extra info: Ideally I need a solution that effects clothing and props too (basically any other skele mesh I want to add). Otherwise I’ll have to create and implement morph targets for hundreds of items.

Edit 2: So Bizmark gave me the answer of using the “Transform (modify) Bone” node which is almost perfect. I just wish the scale change didn’t effect children. If anyone knows a way around this please let me know!

2

I Have seen examples where people have used Scale to achieve this effect.

As for bone modification itself I dunno.

3

you may want to look into using morph targets.

4

Thanks for the ideas guys. Scale works but effects the whole skele mesh as far as I can tell.
Morph targets are great for different body shapes (Fat thin, etc), but I don’t think they can be used to change proportions?

5

What i meant was to scale the bone itself. Longer arms etc but there are things about that that I am fuzzy on. Thompson is really good at explaining things I m sure he can muster a solution for ya.

6

First of all, I would second using blend shapes/morph targets. But…

Have you tried the “Tranform (Modify) Bone” node in the animation blueprint?

I have never used it in production but have found it fairly decent in prototyping.

7

Aah I see thanks Exonfluxx. I’ve experimented with scale before and seem to recall it messing up the pivot points.

I’m trying morph targets now and it seems to have roughly the right effect; is there a way to have the morph somehow effect clothing/props without having to make morph targets for each of them? I should have mentioned there are going to be a lot of customisation options clothing-wise.

8

Ah that looks promising, thanks Bizmark I’ll look into that. The issue I’m having with morph targets is that they require new targets for each clothing item (which is lots). It’d be ideal if there were a way to effect the rig and have that change translate to any skinned items, rather than having to create hundreds of different blendshapes for all my objects.

Edit: Looks like Transform (modify) Bone was just what I needed, although now I need a way to stop scale changes affecting child bones. Thanks again Bizmark!