   D3DXComputeBoundingSphere and D3DXComputeBoundingBox
  Does anyone here knows what's the math behind this two function? I want to know how it is done.   
  D3DXComputeBoundingBox is probably something like...D3DXComputeBoundingBox( list_of_vertices ){vector min = vertices[0], max = vertices[0];for_each( vertex in vertices ){  if( vertex.x < min )  min.x = vertex.x;  if( vertex.y < min )  min.y = vertex.y;  if( vertex.z < min )  min.z = vertex.z;  if( vertex.x > max )  max.x = vertex.x;  if( vertex.y > max )  max.y = vertex.y;  if( vertex.z > max )  max.z = vertex.z;}return boundingBox( min, max );}Then from that you can compute the bounding sphere, i think something like...boundingBox box = D3DXComputeBoundingBox( my_mesh_vertices );boundingSphere Sphere;Sphere.radius = distance( box.min, box.max ) / 2.0f;My math isnt that great but it looks right to me.   ;  Hi,fitfool looks right. But just to add, bounding spheres have a Center point. And it can be calculated by dividing the sum of min and max vectors by 2. Note that min and max points are both in model space. If you want to use'em correctly, you must first multiply'em by model's World Matrix.   