57 minutes ago, Sword7 said:

Interesting.  Where is Heli Engine?  That did not provide any information but just video clips.

Well, I found a book called "Physics Engine" book provides a lot of information about collision detection. I recommend two books - "Collision Detection" and "Physics Engine" for collision detection.  I think that they explains  can detect collision when hit a rendered tile.

Haha dude, its my own engine I did during my phd,  you can also find this in my projects. So I pretty sure about what this engine does))

Btw I thought not about physics but just raycasting, so terrain in my heli demos not more than just a box with height map projected on its bottom, and actual rendering is in pixel shader.

It seems I understood the question not 100% perfect but I thought the question is about raycasting e.q. visualising sperical terrain without polys, ok, almost,  just using 6 polys per box-like patch