@jgonzalez
thanks for your answer, the problem ist like here described in the video but solution for 3d max…
https://youtu.be/1QbpCZuGe7M
and I tried to paint with vertex color the mesh on the base. it has 3 planes with grass alpha textures. I wanted to paint as mesh detail for a landscape. But it still slides…I tried export as fbx, as obj, as blend file directly….