Techniques generally disclosed herein relate to computation of a guard zone of a three-dimensional object. In some examples, guard zones may be computed by identifying intersection lines that couple adjacent planes of an object, and categorizing an external angle at an intersection line between adjacent planes as concave or convex. In some embodiments, for convex angles, a cylindrical surface can be determined that is located about an outside surface of the object and centered along the intersection line between the adjacent planes. In some embodiments, for concave angles, the external angle can be bisected with a bisection plane. A guard zone may be formed by one or more of (i) providing a guard zone plane parallel to the object that is a tangent to a given cylindrical surface, (ii) providing a guard zone plane parallel to the object that intersects a given bisection plane, and/or (iii) coupling adjacent guard zone planes.