On 07/03/2017 at 12:51, xxxxxxxx wrote:
User Information:
Cinema 4D Version: R18
Platform: Windows ;
Language(s) : C++ ;
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I was wondering about detecting reversed UVs, and tried the following:
Using a UserArea I draw the UVs (color coded by island) and check the winding of the UVW edges. When winding is counterclockwise I draw a dot at the barycenter of the polygon.
Now I have this sphere which I unwrapped into 3 islands, and see that the blue one is reversed.
The white edges (candidate selections) in the viewport and the UV view clearly indicate that the island in the UV view is reversed. Also the textured version of the screenshot (see below) show that this blue island has reversed UVs.
But when I look at the dots, I only see some of the polygons of the blue island being detected as having a counterclockwise winding. I would have assumed that all polygons are reversed, since the textured screenshot clearly show all the texture parts assigned to the polygons of the blue island being reversed.
Strangly, also the non reversed (red) island does have a single UV polygon detected as reversed, while its texture is not reversed.
So, is this just a wrong assumption to try and use this winding to detect an UV polygon being reversed, or am I missing something?
I thus far have noticed that "reversed" UV islands have more than 50% of its UV polygons detected as having counterclockwise winding, while a non reversed island has less then 50% UV polygons detected as having counterclockwise winding. So, would this be the criteria to detect if an UV island is "reversed" ???