More jiggle

I wanted to try and make additional jiggling and surface deformation, without making the mesh denser for the physic simulation to handle. Having more jiggle is always nice when the belly gets squeezed or slapped.

This can be done with dynamic paint. With dynamic paint, you have a canvas (one canvas per effect), which in this case is the body, and a brush which is the hands. When the brush gets in contact with the canvas it does something. It has a bunch of options, and I want to use two of them, one is the deformation and the other is wave. I did test it a long time ago with a ball colliding with the fat wolfs butt, the results looked pretty nice.

This time it’s the hands that need to collide with the body.

I duplicated the hands to use as brush for the dynamic paint with the wave and deform brush. But the hands immediately started to go crazy. I thought it would work as the collider mesh is outside of the hands but it does take the volume of the brush into account, so the hands would be affected.

 I tried to search for a way to exclude the part of the mesh that shouldn’t be affected, but I could not find anything.

Initially I tried to cut the hands off and remove the option for them to be affected by the dynamic paint brush. That works, but I don’t like separating the mesh in a destructive way.

Maybe I could use a modifier called 'Mask' on the body instead. This allows you to exclude the mesh and be hidden from renders, but I didn’t know if it would exclude the mesh completely, it was worth a try.

I duplicated the character hands, removed their dynamic paint option and masked the hands on the body. I gave the duplicated hands the dynamic paint modifier and made them a brush. Now it only spikes at the wrist where the body mesh meet the hand mesh. Sometimes it works though, and it won’t spike. The mask excludes the mesh from everything, this is excellent!

I removed the dynamic paint option on the hand mesh, just to keep them as colliders for the cloth physics to interact with. Then I duplicated the hands again, making them invisible form the renders, removed their colliders and gave them dynamic paint brush option. The hands are finally still.

Now I just need to make a small animation to see how it looks in motion. I hope it wants to stay stable. The dynamic paint started to misbehave when using a subdivision modifier with 2 subdivisions. It seems to be stable by activating cloth modifier. This is how the initial slap test looks x).