   Plz help me find normal vectors...
  Hi I'm new here. I always got great helps from gamedev.net. This time I just couldn't find the solution to my problem anywhere, and I was stuck for so long... so I just registered here hoping someone can plz help me! :(I downloaded a human head mesh data from a website, but it just has vertices and triangles connecting them (no normal vectors). So I did the old fashioned way (multiplying two vectors to get normal vector) to get them, but here's the problem. The guy who made the mesh didn't seem to care about the left or the right hand rule when he's connecting vertices, so normal vectors are wrong, some going in and some going out.There are too many triangles to fix by hand. Is there a way to make the vectors point to only outwards? Like, if you could set a point (inside the head) and from two possible normal vectors of the triangles, you could choose the one pointing away from it...Any support will be appreciated. Thank you for reading.Or if you know a good human head mesh for sharing, that would be equally appreciated :)   
  I don't know of any algorithm that can correct the normals but there probably are some.Nevertheless, maybe you can do something like this to get most of the triangles wound correctly:1. Generate some adjacency information for your triangles, so that you can find a triangle's neighbors2. Somehow iterate over the triangles, starting at one triangle and continuing with its neighbors. You could set a flag on processed triangles and only add neighboring triangles on the to-be-process list if they are not flagged yet.2a. for each triangle (except for the first) check the angle between that triangle and its already processed neighbor and the angle between their normals. If the angle between the normals is the angle between the triangles - 180°, then both triangles are wound in the same direction, otherwise not.Hope that helps.   ;  Check Trimesh2. The tool "mesh filter" can correct normals.http://www.cs.princeton.edu/gfx/proj/trimesh2/   ;  Thank you guys so much for your feedbacks. I haven't tried out yet, but I think both methods will work great :D I knew gamedev.net has some coding gurus who can help me! TY!btw, for anyone curious or anyone who was looking for a head mesh and googled upon here, here is where I got it:http://grail.cs.washington.edu/projects/realface/geo.txt   