Decimated parts falling into each other I created a plane, subdivided and decimated it. After that I edge split the plane to create multiple triangle. To give them a 3rd dimension solidify was used. 
When I now want to animate the triangles falling down on a rigid plane, everything works fine so far except that the triangles fall into each other. Is there a way to prevent this? I played around with self collision but nothing I did helped. Do you have any tips?
Since you are using a single object, you have to enable Self Collision to allow parts of itself to collide with itself.



However, you will need a lot of accuracy and samples. The situation of many rigid pieces would be better suited with a Rigid Body Simulation.