Comments on: Two-Sided Drawing and Up-Normals https:/2010/04/two-sided-drawing-and-up-normals/ Developer resources for the X-Plane flight simulator Tue, 01 Feb 2011 19:01:08 +0000 hourly 1 https://wordpress.org/?v=6.6.1 By: rca_guy https:/2010/04/two-sided-drawing-and-up-normals/#comment-409 Sat, 10 Apr 2010 02:50:11 +0000 http://www.x-plane.com/dev_blog/?p=87#comment-409 I recently converted a scenery with FS2XPLANE and it created trees with "correct" normal vectors, which looked completely "wrong", just as you say. I experimented a bit and found that there is a way to get some better lighting:
http://sites.google.com/site/omsipanos/Home/tree_demo.jpg

The normal vectors are up, but 45 degrees outward bent and still in the plane of the texture – allowing for some directional lighting. In this case, the "incorrect" backside lighting of the two-sided triangles is just fine.

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