# Questions tagged [convex]

"Convex" describes a shape whose interior angles are all less than 180 degrees - it has no concave valleys anywhere. Convex polygons and convex polyhedra are often used in collision detection, because they're simpler to evaluate than concave shapes.

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### What is the minimum number of points in a convex hull in most engines?

A convex hull shape in a 3D game engine defined by vertices needs at least 4 points in order to have volume, since that would make it a tetrahedron. However, some game engines may support fewer points,...
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### Shrink a convex polygon

Shrinking a concave polygon is quite hard, to do well. But I expect shrinking a convex polygon would be easy. The naive approach of moving each vertex a certain distance to the centre gives me poor ...
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### How do I test for collisions between two concave shapes decomposed into collections of convex polyhedra?

I am using convex decomposition with SAT (separating axis theorem) and I generate two arrays of convex pieces, How do I submit my arrays to my collision detection method which only takes two arguments....
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