Fluid simulation with animated mesh problem

The attached blend file has a dinosaur stepping into fluid on a ground plane. In the screenshot you can see that the fluid is not responding properly to the animated mesh.

For some reason the fluid sim thinks the dinosaur foot is behind where it is, and doesn’t respond to its motion at all. Any ideas?

Thanks in advance!


allosaurus_v08_footshot.blend.zip (975 KB)

Sorry, nope, no idea. I checked your file and you did all that is needed to have a mesh with armature interacting with a fluid simulation… but, for some reason, Blender only acknowledges your armature in rest position.

I made a quickie. A mesh with 2 bones which comes in and out of a cube of fluid. It works, whether the animated mesh is fully inside the fluid domain or not. (There’s a myth floating around which says that it matters.) Your scene just doesn’t work.

Applying scale to everything (NOT to the armature!) makes no difference. Changing the time of the simulation to use real time instead of slow motion, makes no difference. A bigger fluid block makes no difference.

I found nothing weird like triple unused modifiers, mind-bending shape keys, drunk drivers to take Blender off the road… You can hardly call weird a few bone constraints with no effect. So…

What did you doooooo? :confused:

The Fluid Sim modifier needs to be below the Armature modifier

Doh! How could I miss that? :no:

I’m not the OP but, thanks, Richard. :wink: Mystery solved.

That’s great! I totally forgot about the modifiers. Thanks!