thank you for your reply.
thin, I thought panda3d could make me a spherical plane natively 
Iām starting with panda3d and i have no idea how to do it 
For physic engine, i can use Bullet, thank you for your advice
Looking at the documentation of Bullet, for handle collision in a ShaderTerrainMesh i must use BulletHeightfieldShape.
i found example here :
[BulletHeightfieldShape problems with latest panda builds)