How to bake softbody animation into keyframes?

Question

I am trying to bake a softbody animation into keyframes but I can't, does anyone knows how to do it? Thanks!

Answer 1

You can't bake softbody into keyframes anymore, blender uses shape keys now. So you would need to generate a shape key for every frame of animation and also keyframe that shapekey to its frame. You do that with running this script:

import bpy

obj = bpy.context.active_object
start = bpy.context.scene.frame_start
end = bpy.context.scene.frame_end

def insert_keyframe(sk, f):
    sk.keyframe_insert("value", frame=f-1)
    sk.keyframe_insert("value", frame=f+1)
    sk.value = 1.0
    sk.keyframe_insert("value", frame=f)

meshes = []
for f in range(start, end+1):
    bpy.context.scene.frame_set(f)
    meshes.append(obj.to_mesh(scene=bpy.context.scene, apply_modifiers=True, settings='PREVIEW'))

obj.shape_key_add(name="Basis", from_mix=False)
for i in range(0, end-start+1):
    key = obj.shape_key_add(name=str(i+start), from_mix=False)
    insert_keyframe(key, i+start)
    for vert_id in range(len(obj.data.vertices)):
        key.data[vert_id].co = meshes[i].vertices[vert_id].co

for mesh in meshes:
    bpy.data.meshes.remove(mesh)

Don't forget to turn your modifier off or to delete it (or it will override the shape key animation)

Also you can export your softbody animation as an New Tek's .mdd mesh cache format (export addon will do this) and load this file into Mesh Cache modifier. This allows you to for example offset the animation and further manipulate it.

Answer 2

I need to chime in, just because I had the same question - but wound up with a different take on kind of the same answer as above:

I agree with the sentiment that "you can't bake them into key frames" anymore - but you can run the script above to do so - however, (at least in my case) what I wanted to do was to tweak and better control how/when/where the animation was played back.

So in my case, merely animating the shape keys themselves was ideal. This means, after you have your softbody/cloth or whatever simulation - go into the "modifier" and "save to shape key". Then, just animate that shape key in the graph editor/dopesheet - just as you would have done to your mesh.

This is actually much cleaner than editing animations recorder through the blender game engine (which is what I thought it would be like to "export" the physics mesh animation to keyframes) - where you would have one keyframe for every frame. (This is what the script above gives you - and you wouldnt' need that either). You just have keyframe points at any time you create a keyframe for your shape key changing.

Sorry for the longwinded explanation - but now I understand why they mad you do it with the shape keys - and am happier for it!

Answer 3

Updated version of the script, that works with Blender 3.3.1:

import bpy

obj = bpy.context.active_object
# note: you can just set start and end frame numbers manually
start = bpy.context.scene.frame_start
end = bpy.context.scene.frame_end
dg = bpy.context.evaluated_depsgraph_get()

def insert_keyframe(sk, f):
    sk.keyframe_insert("value", frame=f-1)
    sk.keyframe_insert("value", frame=f+1)
    sk.value = 1.0
    sk.keyframe_insert("value", frame=f)

obj.shape_key_add(name="Basis", from_mix=False)

for f in range(start, end+1):
    bpy.context.scene.frame_set(f)
    obj_evaluated = bpy.context.object.evaluated_get(dg)
    mesh = obj_evaluated.to_mesh(preserve_all_data_layers=True, depsgraph=dg)

    key = obj.shape_key_add(name=str(f), from_mix=False)
    insert_keyframe(key, f)
    for vert_id in range(len(obj.data.vertices)):
        key.data[vert_id].co = mesh.vertices[vert_id].co

    obj_evaluated.to_mesh_clear()

Note you still need to remove the modifier afterwards.