Isoptic surfaces of polyhedra

The theory of the isoptic curves is widely studied in the Euclidean plane $\bE^2$ (see \cite{CMM91} and \cite{Wi} and the references given there). The analogous question was investigated by the authors in the hyperbolic $\bH^2$ and elliptic $\cE^2$ planes (see \cite{CsSz1}, \cite{CsSz2}, \cite{CsSz5}), but in the higher dimensional spaces there are only a few result in this topic. In \cite{CsSz4} we gave a natural extension of the notion of the isoptic curves to the $n$-dimensional Euclidean space $\bE^n$ $(n\ge 3)$ which are called isoptic hypersurfaces. Now we develope an algorithm to determine the isoptic surface $\mathcal{H}_{\cP}$ of a $3$-dimensional polytop $\mathcal{P}$. We will determine the isoptic surfaces for Platonic solids and for some semi-regular Archimedean polytopes and visualize them with Wolfram Mathematica.