I posted this a few days ago on a different thread but didn't get any response, so instead of highjacking that thread I thought it best to start a new one. The issue is very simple, I created two 2D polygons and wanted to combine them (using the menu command, Compose) and then extrude it.
PROCEDURE Test;
VAR
poly1, poly2, polyOut : HANDLE;
TF : BOOLEAN;
BEGIN
Poly( 0,0, 10,0, 10,10, 20,10 );
poly1 := LNewObj;
Poly( 0,0, -10,0, -10,10, -20,10 );