I am currently reading Christer Ericson's Real-Time Collision Detection Book. The topic I'm particularly interested in, is the chapter about Discrete-orientation Polytopes (k-DOPs). In his words "...k-DOPs are convex polytopes, almost identical to the slab-based volumes except that the normals are defined as a fixed set of axes shared among all k-DOP bounding volumes. The normal components are typically limited to the set {−1, 0, 1}, and the normals are not normalized... Only the min-max intervals for each axis must be stored." So for example a Cube of side-length 2 can be written as a 6-DOP with face-normals [(1,0,0),(0,1,0),(0,0,1)] and the min intervals would be [-1,-1,-1] and the max intervals [1,1,1]. Another example would be a octahedron (8-DOP) with face-normals [(1,1,1),(1,1,-1),(1,-1,1),(-1,1,1)].

Given the face-normals and the min-max intervals, I'm interested in calculating the vertices of the polytope. My first intuition was to calculate the linear equation system of every combination of 3x3 Matrices (face-normals) with every combination of 3x1 Vectors (corresponding min-max values). This works very well for the 6-DOP example, since there is only one 3x3 Matrix and exactly 8 combinations of Vectors, leading to exactly 8 linear equation systems. The result of these equations, are the Vertices of the cube. In other words, I just calculate the intersections of all groups of three faces that are not parallel to each other. However, this approach fails for higher values of k, like the 8-DOP, since there are intersections out of the k-DOP and therefore far too many Vertices calculated.

I am looking for a simple algorithm, to calculate the vertices of every given k-DOP. The algorithm can be a brute-force approach, as computation time is not relevant to me. What is important to me is an approach that is easy to understand. In another question (Finding a bounding volume (line segments) from a kDop definition.), a fast approach was suggested. As embarrassing as it is, the suggested approach is currently way over my head. In his question the author said he used a "Brute force method. Intersect each plane with each other plane to get a set of lines and then intersect these lines with each plane to find the correct line segment (or discard the line)." I'm not sure how to determine whether a line segment should be discarded or not.

Thanks to everyone helping in advance!