Rounded tetrahedron

Download rounded_tetra.inc.

This is a simple macro that creates a tetrahedron with rounded edges and vertices. It takes two parameters: a, the size of the tetrahedron, and b, the radius of curvature. The tetrahedron is fitted into a box with edges of length 2*a as shown below:

As can be seen, the curvature stands proud of the container. By default the macro is a union; if you need to use transparent textures this keyword should be replaced with a merge. When manipulating the tetrahedra, the angles f_f and f_e (the angles between two faces, and a face and an edge, respectively) are useful when aligning a face with a plane - for example, the following code will align the tetrahedron's base with the x-z (ground) plane:

Since these angles are declared locally in the include file it may be useful to copy them into your scene file.