Custom Collision for Sims

This is something I have not seen in any software as far as I know say for game engines.

When it comes to creating sims you have use mesh or a preset but sometimes the mesh option is too slow and the preset is off.

I was thinking maybe you can custom model a collision box for it lp but better fits the shape.

I am the type of modeler who likes using a lot of sims to naturally scatter stuff, stack stuff etc however it can be a pain if you have a HP model that you want to behave a certain way but not take all day.

For instance you want it to fall into place as if it was of the shape it is, but to do that you have to use the mesh's collision which if HP can take forever. However the other option that can be faster does not have an accurate shape aka primitives, now you may go well you have the other option which tries to make the shape, yes it does but it fails quite often. If you can make a mesh that is half-decently LP that fits the shape better and apply it a collision it could be a middle ground better results with slightly faster times.

I had a crinkly log that could have used this method once upon a time. I do not have a render of this one though. It was somewhat HP due to the crinkles however it was shaped like a cylindrical pizza slice round outer edges triangular sorta inner with some lips in it as well. It did not behave well.

Sorry to flood this place with so many suggestions but these guys could make a huge difference. Who knows maybe my suggestions will spark something in others. Thanks for your time.