This is very odd and I can't figure it out.
The model is an explode/breakable object. The base is a lathed cylinder shape with 3 Newton_ groups defining the density. The bottom group is the heaviest and set to a density of 9. The group above it is 6. The long thin part is 1. Above that is the sign board and all the letters.
It is all resting on the ground plane (static object) very close but not touching. The ground is a large grid. I replaced the original 1 patch ground with a grid to see if it made any difference... no difference. A cube (dynamic object) in the chor hits the top of the sign causing it to rock and roll a bit. It usually works fine but every once in a while you can see that the base will penetrate the ground plane causing the "wobble" to increase and continue. I tried everything. I even increased the bounding hull to 16. I checked the bounding hull models and they do match the shape but are not "round". It is made up of flat edges. Could this be what is happening? Some of those "pointy" areas are getting "under" the ground?
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Any advice or input would be appreciated.