I’ve built a critter in blender and rigged it using rigify.
The critter has some non-standard mouth parts that I would like to squash and stretch when the lower jaw moves. I’m pretty new to Blender so am struggling to figure out how to get the mouth danglers to behave in the way I would like them to. Here’s a picture of the model, the bones and the current squash/stretch behaviour.
I would like the fleshy strips to compress and stretch in a linear manner, rather than bending.
I tried using weight painting, but i’m not sure that’s the correct approach. I also tried adding a bone for each of the danglers and then parenting that to the lower jaw, but then they all just moved together. If I could anchor the tip of those dangler bones to the upper jaw, then the bones would scale and I suspect it would give me the effect I desire, but I don’t even know if that is possible.
Any advice on how to make them squash stretch correctly would be most appreciated.
This is an example of the bones that I created for the fleshy danglers (i’ll refer to them as flanglers from now on). Constraining the movement of the bone tips would result in them scaling when the lower jaw moved (as that is their parent).
You can add a couple of ‘anchor’ bones to the ends of the bones that you want to stretch, and parent them to the upper and lower jaw bones.
Give the anchor bones the skin.anchor Rigify Rig type, and tick the Suppress Control option for them (unless you want an extra control to adjust things).
Set the Rigify Rig type for the stretchy bone to skin.basic_chain.
As long as the anchors are positioned at the head and tail positions of the stretchy bone, it will all get hooked together when you generate the rig.
Whilst your instructions were absolutely spot-on, my lack of rigify knowledge hampered me. I hadn’t actually generated a Rigify rig and was trying to just use the Armature rig.
Once I’d spent a few hours skilling up on Rigify, I was able to dissect the example file you provided and understand it fully. The flanglers now stretch as they should.