Apply cloth simulation to a rigged character that already have shape keys?

What i’m trying to get here is pretty complex. I have an already fully rigged and animated dragon and added some shape keys to it to make it more natural, blink etc.

Now i would like as a final touch to add cloth simulation to it, to make some body parts jiggle. It works pretty well for the moment in viewport and viewport rendering but when i try to apply it, it’s not possible because “we can’t apply modifiers to a mesh with shape keys!”.
So i try to apply it as shape keys, it’s not possible because the modifier is not first, because there is the armature first. So i try to apply the armature, but, “we can’t apply modifiers to a mesh with shape keys!”.

I’m also constating that i no longer can modify shape keys on the moments with cloth simulation (that is not necessarely a problem, if i complete them before)

Lastly; i did a lot of fast bakes for different tries and it just made my blend crash.

So i’m asking if it’s possible to make this work, and is it ok for Blender for a long animation (+8000 frames) or is it a bad idea and should i stay with my shape keys? thanks by advance for any infos about the shape keys / cloth sim relation!

Why do you want to apply the cloth ?
There is a way to get to what you want , but it’s quite tedious…

You can duplicate as many dragons as you’ve got shapes keys, then erase the shapes, if you want to keep the blink, you just erase the shape blink once everyother are ereased.
The idea is to have every models with different shapes, but without shape keys.
Then you do you cloth stuff, convert it as shape, and finally join all the mesh as shape keys.

I’d personnaly would try to keep the cloth as a modifier and try to make something good from it without applying it.

So you want to apply the cloth as shape keys to avoid the crash ? are you using disk cache ?
Maybe you’re not and when baking the memory get full ?
8000 frames is a big number, it should eventually be working but maybe you miss an important point.

2 Likes

Hi, i wanted to apply the cloth sim because i have the sensation that it make the scene quite instable and also very slow. It regulary totally waste the mesh when i’m moving on timeline, also it make shape keys not work some times, made my blender crash etc… But i’ll try that you said to keep it as a modifier, i’ll apply it only at the very end when all my movements and shape keys will be done.
With some patience it should work. Normally I have some disk cache applied but i’ll recheck.
Also here the duplicating dragons tips will not fits because of the too high number of shape keys, but i keep it in mind for future projects. THanks YOU

I don’t think you want to apply the modifier. Applying the modifier makes it so that it assumes the position it has on the frame that you applied the modifier. Once you apply the modifier, it will no longer be physical, it will be static.

The slowness of cloth physics, and its need to be recalculated every time anything changes for accurate timeline scrubbing, is just a fact of life of physics. The most that you can do is reduce vert counts (or occasional cloth parameters) to improve speed.

If you want to apply cloth physics, try the “apply as shapekey” operation from the modifier’s dropdown, which, instead of applying the physics, will create a new shapekey with the physics (only) applied. You can set this new shapekey to 1.0 if you want. This might help you see if you really do want the physics applied.

Yes as bandages pointed out, and given what you’ve said applying the cloth modifier isn’t a good idea…

Alright thanks you, then i think i’ll wait to finish my whole scene / anim and then maybe apply a cloth simulation at the end when all will be ready for final render, to make it still usable before without being ultra slow. Considering there will be other simulations (mantaflow) too i’ll have to go with learning compositing probably to keep my scene usable. ty again for the infos!

Again, I don’t think that applying the modifiers is what you want to do. You might want to bake your physics, which isn’t the same thing, and which can be done regardless of the presence of any shapekeys on physics meshes. I would recommend doing a few simplified tests in order to understand exactly what the difference is between these two things. But if you don’t want to, you’ll see when you get to it, that’s fine.

1 Like