   Another Frustum Detection Question
  Thanks for the replies on my previous post with regards to this... but it turns out that knowing whether a point is in a frustum is not sufficient for my needs.Say, I have a cube of arbitrary size, composed of 12 triangular faces. How would I go about detecting whether any part of any face of this cube is within a frustum? In this case its possible parts of the faces are within the frustum, while none of the 8 corner vertices are within it.If you'd like me to supply any more specific info to help frame this question, I'll be available to do so for the next several hours.   
  I think you mean 8 corner vertices. In any case, you can test for the corners of the frustum being within the box. [ after some thought ] Unfortunately, that won't detect the particular case where the bottom and top of the box are below/above the frustum and the sides are all within the frustum.Sorry about that.   ;  Create a axis aligned bounding box for your cube and transform it in to viewspace and check those vertices aswell.[attachment=1111:frustum aabb.png]If you are using huge models and that's the problem then you could subdivide some faces for frustum checking   ;  No per-vertex checking should be necessary. Instead, test the box against each plane by computing the orthogonal projection of the box onto the plane normal (which can be done very cheaply). This form of the AABB-frustum test is conservative in that it can return false positives in some cases, but that's fairly standard (the rationale, I would guess, being that the greater efficiency of the AABB test tends to make up for any false positives that might occur).   