   2D collision detection with polygons and silhoutte creation
  This is actually two questions in one.1) How do I do collision detection on 2 random polygons in a 2D environment?What I would do, I would loop through every point of Poly1 and check if its inside Poly2 by checking if the sum of the angles from Poly1.point to any point of Poly2 is 360 degrees.Would this work? I can think of a situation where no points intersect but a collision is happening. What other methods are there? Are they too expensive to apply compared to the "see if point is in poly" method?My second question:2) How do I create a silhouette of a 3D model?If I want to do collision detection in a 2D plane, I need a 2D shape. I plan on using 3D models, so I need to calculate the silhouette somehow. What methods are there? Any pointers to concepts/articles that describe this?Thanks for your help. 