Physics Engine Terminologies (Noob Question)

[doc_180]

As you might have understood from the title of the question, I am a newbie to Game Programming and Physics Engines. I was reading through the Bullet SDK Manual and could not understand some of the terminologies used. For instance, I could not understand what a collision shape is ? ( and my google search results were not very revealing).

I apologize if this question is very basic and please do not mistake me for a lazy programmer. Its been a long day and I have had too much information loaded in to my primitive brain. > Thank You.

Edit: Immediately after typing in, my brain gave me a cryptic clue. ( I remember reading this in an article, during this long day). I assume that to simplify the physics calculation, complex objects like a meteor will be internally represented by a simplified geometric model and this internal representation is probably what the collision shape is? Please correct me If I am wrong.

[Dirk Gregorius]

Exactly! Don't make things more complicated as they are

[Karrok]

Collision shapes are the shapes that Bullet uses to calculate its collisions with.
It's kinda in the name .

And yes, usually these are simplified versions of their visual counterparts. Ranging from the most simple convexhulls to more complex trimeshes or even compound shapes.

If the physics engine had to handle exact model copies of extremely detailed and complex models the collision detection could slow down significantly.

ie, a world filled to the brim with 10.000+ vertice trimeshes as collision models is probably a bad idea