So I was going to create my normal map and noticed that my straight lines became crooked when I placed the map on my model. I then zoomed in on the UVs in blender and saw the crooked lines.
The top part of the image is the model, and the bottom part is the UV editor.
Why do my UV come out crooked when the UV is straight!?
The model is a sphere. The weird part is that the lines on the edged of the map are straight when I put it on my model but the lines between the edges are crooked like below…
No I just tried it myself with the default UV sphere and this happens without subdivision and regardless of Smooth/flat shading. Very strange thing. I can see seams on the diagonals that would get triangulated if you perform a Face>Triangulate, but why this happens ? Picked my curiosity.
Wow ! Just create a plane, scale one edge and this happens ! Crazy. It’s clearly because of the triangulation now. I’m not sure there’s a way out of this except subdividing.
But it’s pretty understandable actually. Backdoors, Blender is just dealing with triangles, you can’t do much about that.
I wonder if other programs have found ways to fix this.
So the answer would be to use subsurface on my sphere to make the triangles smaller and make the lines in the model and then bake the normal map. Then use a lower resolution sphere in the game with the high res normal map?
Yes, using Selected to Active in the Baking options (the high poly is selected and the low poly is active). Also enable Smooth shading or you will get artifacts on the edges. It still gets weird around the poles, I dunno how to fix that yet.
Oh, I got it. It’s because you don’t want to use a subdivision modifier on your sphere but instead create a new sphere with more divisions (the subdivision modifier makes a different topology around the poles)
So I made a LowPoly version of my “sphere container”. Before I made all the little details on it, I unwraped it and saved that model as LowPoly. I then copied the LowPoly and added Subsurf on that and made all the details on that. Saved that as HighPoly and used xNormal to make the normal map. The result was crappy, but I filled in the lines and stuff and at the end, it came out great. I used Quixel Suit NDO to make the normal map details better : Results down below with highpoly normal map on my lowpoly sphere
