I’ve made a model of a human and rigged it. What I want is to be able to change the age of the character from a child to an adult. I understand how to change shapes of particular body parts using morphs. But how can I change the character height and proportions, while still being to able to use the very same skeleton. Is changing bones length in pose mode ok? I mean will it cause any issues with pre-made animations?
Can I assign it to some kind of “age slider”? Sorry, I’m completely new to animation.
Also, I an going then to export this character to UE4 (or 5, not sure how stable UE5 at the moment), and use all animations and this “ageing feature” there.
Yes, you change character proportions with the armature, rather than with shapekeys or anything else. Changing bone lengths will affect pre-made animations, which are built around certain expectations of proportions. The details depend on the rigging style (IK legs, for example?) For example, an animation may have a character touching their face. If their forearms are shorter, they won’t reach their face; if their forearms are longer, they’ll stick into their head. But this is a problem with using pre-made animations on models with different proportions from those intended, not with changing bone lengths during an animation. Changing bone lengths during an animation is fine (other than the fact that it’s not realistic.)
You could make a custom property called “age”, which has a slider, and use it to drive any number of properties, including action constraints that changed bones’ lengths. It’s probably not the most work efficient way to do things though; I would probably make an “age” action, and use NLA to blend it in to another animation.
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