Wow!! Thanks a lot, for pointing me to the google ;) But I afraid that maybe I've not correctly describe my problem. If so, sorry for that, because my english is still kinda weak. My problem not in generating a normal maps (a textures) in blender. Not at all.
My problem is that I cannot fully correct render my already generated normal maps in my app. Because, how I mentioned in the last mail, the usual methods for this purpose (by UV coords) is not gives me desired results. So I wanted to ask for help with information about methods blender uses for generating tangents. And yes, I had searched in google but unfortunately have't found something helpful yet. If someone can point me to that kind of info, I will be very grateful! On Mon, Nov 14, 2011 at 12:08 AM, Morten Mikkelsen <mikkels...@gmail.com>wrote: > There you go buddy --> http://lmgtfy.com/?q=blender+tangent+space > > > > On Sun, Nov 13, 2011 at 8:46 AM, Eugene Minov <minov....@gmail.com> wrote: > > > Hi. > > I am sorry if I subscribe into a wrong place, I am new and I've not > > actually planned to change or to debug the blender sources yet. > > But I trying to write app that'll be render models with normal mapping > > exported from blender, and I have a question about how exactly is blender > > calculates a tangent vectors when Unwrap operation in the editing mode > > performs? > > > > Calculating tangents in my app in usual manner (using UV coords and verts > > positions) gives me different tangents for each face of the same vertex > > indexed from, and thus crumpled normal map looking. > > Then by looking into blender sources (searching by 'tangent' keyword) > I've > > found a couple of functions with tangents calculations, like: > > float axis[3] = {0.0f, 0.0f, 1.0f}; > > cross_v3_v3v3(tangent, normal, up); > > normalize_v3(tangent); > > > > After I tried same method in my program I've gotten almost perfect > looking > > model, depending on what initial axis I've used. > > To choose, which axis to use (0, 0, 1), (0, 1, 0) or (1, 0, 0) for each > > normal, I calculate max dot product of tangent calculated by each axis > with > > tangent calculated from UV coords. > > But still it seems that in some rare vertices tangent is calculates > wrong, > > maybe because of wrong initial axis. > > > > So, can anyone please give me any information about tangents calculation > > formula that blender uses while generates UV coords or some advice about > > choosing initial axis. > > Thanks for help. > > > > Eugene > > _______________________________________________ > > Bf-committers mailing list > > Bf-committers@blender.org > > http://lists.blender.org/mailman/listinfo/bf-committers > > > _______________________________________________ > Bf-committers mailing list > Bf-committers@blender.org > http://lists.blender.org/mailman/listinfo/bf-committers > _______________________________________________ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers