<html>Dear Christophe, colleagues,<br /><br />Recently there was a question about identifying different patches of am STL 3D surface mesh, and get the list<br />of elements on that particular surface.<br /><br />I face the same problem. I created the bounding boxes or cylinders, GMSH objects, of the surfaces of interest to me, (see the figure attached for my geometry and the bounding cylinder object<br />Cylinder(8) = {3.05, 3.05, 5.02, 0.1, 0.1, 0, 0.060, 2*Pi};).<br /><br />Can I use boolean operations somehow to find the intersection of these 2 surfaces? Or any other clever solution? I think general computational geometry methods would be overkill.<br /><br />Many thanks for reading!<br /><br />Best wishes,<br />Zuheyr<br /> </html>