Collision detection between Solid BSP tree and OBB?

as far as I remember, the fat-BSP requires only a function that outputs the support vertex of an object along a plane normal. So in that case, the beveled plane equation for a given box is

d = (N * Box.Centre) + fabs(N * Box.DirX) * Box.HalfSize.x + fabs(N * Box.DirY) * Box.HalfSize.y + fabs(N * Box.DirZ) * Box.HalfSize.Z;

(N.x * x) + (N.y * y) + (N.z * z) + (-d) = 0

Centre is the centre of the OBBox. DirX, DirY, DirZ is the orientation of the OBBox, HalfSize if the extent of the box along DirX, DirY and DirZ. N is the normal of the plane.

Thanks! I''ll try this out.

actually, I was a bit too quick on that. The way I understand the algorithm, you have a plane equation in the BSP stored as

(N.x * x) + (N.y * y) + (N.z * z) + d = 0

and you simplify the BSP/OBB collision by reducing the test to a single ray with beveled planes. Then the beveled plane becomes

r = fabs(N * Box.DirX) * Box.HalfSize.x + fabs(N * Box.DirY) * Box.HalfSize.y + fabs(N * Box.DirZ) * Box.HalfSize.Z

(N.x * x) + (N.y * y) + (N.z * z) + (d+r) = 0

and you cast a ray from the box centre along the box displacement.

I am not sure if it is (d+r) or (d-r) in the plane equation, but it should be pretty clear once you try both if aren''t sure yourself.