please help point in concave polyhedra dear netters i am looking for c source code to test if a d point lies within a concave polyhadra i have read a few articles about this and know that two solutions exist parity counting and angle sumation both ideas are pretty simple but coding is not so i wonder if there exists public domain source code for this another rough solition don t care special cases is ray casting which is reported to be more or less independent of number of faces consisting the polyhedra if a special space indexing is used m tamminen et al ray casting and block model conversion using a spatial index computer aided designs but the prerequirement is that all the facets of polyhedra have their normal pointing outside of polyhedra how this could be done in practice i have a set of trangles consisting the polyhedra how could i ensure their normals pointing outside the polyhedra the paper mentioned above assumed this is already the case i have also read some standard computer graphics textbook about hidden line removal it says if we make the rule that the normal of a facet pointing toward viewer standing far away from the polyhedra again how to make sure any pointers are welcome yaohong jiang queen s university kingston ont jiangy qucdn queensu ca
