Ok, at last. I figure out whats heppening. Its the default bounding box set by the engine is very small and cube shape. Using c_setminmax( ) solved the problem.


Just to share experience with newbie like me:

1. We must create a very big Hollow Box (in my diagram, its in grey color) to wrap the whole game/stage/level. A Hollow Box is 6 blocks of wall placed like a cube. I'm not sure whether you can use a cube and then flip the normal to be used as Hollow Box even the engine will render correctly.

2. If you don't create a Hollow Box, collision detection for physic entity is still good.

3. The Hollow Box must not be set c_setminmax( ). Otherwise, some c_move become stuck.

4. If you plan to create a dummy bounding box like me (in my diagram, its in teal color), always set to c_setminmax( ) after the entity creation. Otherwise, the engine will set a very small bounding box in cube shape. This is known as "hull" in the manual.

5. ALWAYS press F11 twice to solve collision detection problems. The blue wireframe represent the bounding that will be calculated by the engine. If you can't see the blue wireframe, it means no bounding box or the entity is misplace.

In my earlier experience, I thought, even some of the entities got no blue wireframe, the bounding box is still exist but maybe overlap each other. But I was wrong. No wireframe means no bounding!