What I want to achieve : 2-5 meshes all of which have soft-body modifier. I needed them to bounce onto each other, flop off each other, etc.

What I have done so far : Created 2 meshes. Have a plane right below them acting as a surface to bounce on. All 3 of them have a collision modifier. The initial 2 meshes have a soft-body modifier in addition. Soft-Body self-collision has not been enabled, as this itself took an hour to bake. I'm planning to apply this to 5 meshes, rather than just 2, so bake times are crucial for me

Problem : Even when I delete every bake in the scene, re-add a collision modifier + soft-body to the 2 meshes in the scene, the sim starts off with the 2 meshes wrapping around each other, intersecting and clipping into each other, all whilst remaining in the same place, not falling to the ground.

Here is a link to my file : the file

Here is a video of my issue, apologies for bad video trimming and quality :

enter image description here


As with all simulations, start by ensuring you have ‘applied scale’ on each mesh and that the Normals are pointing in the correct direction.

Next, check the ‘cloth and soft body’ settings on each collision modifier - turn the Inner and Outer right down. If you still get intersections, turn the Inner up slightly until it is resolved (but not too high).

Also, you should avoid starting the simulation with intersecting meshes since this can cause very large forces at the start of the simulation.

  • $\begingroup$ I have already done applying scale and normals, and even rebaked with the meshes far away from each other. The issue still continues to happen $\endgroup$ – Hash Jun 27 '20 at 20:59
  • $\begingroup$ I have tried turning down inner and outter down like you said. It stops that horrid wringing effect, but now, there is zero collision between both meshes. They only collide with surface, Is there any way to know the optimal inner and outer values for each mesh? $\endgroup$ – Hash Jun 27 '20 at 21:10
  • $\begingroup$ Looking at your .blend, the meshes appear to be non-manifold, which can cause problems with soft body and collision. Typically, you should set Inner to not more than half of the narrowest part of the mesh. eg, if mesh is 0.1 blender units at its narrowest the. Make sure you don’t set Inner less than 0.05 or you risk the collision from the opposite face dragging vertices through the mesh. Also, you get a better simulation if the faces are approximately square and of similar size to each other - so either retopologise or apply a remesh modifier after you’ve made it “manifold”. $\endgroup$ – Rich Sedman Jun 27 '20 at 23:43
  • $\begingroup$ Nonmanifold means it isn't a closed shape right? Both meshes look close to me. Also, how do I know how thick the thinnest part of the mesh is. Anyway to measure it? $\endgroup$ – Hash Jun 28 '20 at 15:17
  • $\begingroup$ Quite right - I’ve just reopened them on a different computer and they do look manifold now (I think I have a problem on the system I opened it on first). You don’t need to be too accurate with the distance - so just estimate and then subtract a bit to be sure... it’s just to ensure the ‘inner’ region doesn’t protrude through the opposite face. I believe there an addon to measure distances. $\endgroup$ – Rich Sedman Jun 28 '20 at 18:37

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