Some black faces after build illumination

Development Rendering
1

The object of the image has black faces after building the ilumination (Production mode).

Example:

  • screenshot_1: the black faces of the object
  • screenshot_2: marked seams of UV in Blender
  • screenshot_3: UV Map in Blender
  • screenshot_4: normals
  • screenshot_5: tangents
  • screenshot_6: binormals

Does anyone know why this happens?

2

I recalculated the Normals and it seems that everything was correct. The problem persist.

Attached screenshot of the lightmap UV of the object. In this UV I can’t see the polygons that are dark in the screenshot_1. But this UV is automatically calculated by UE4 during the import of the FBX.

Thanks for the help!

3

Yes, the black faces are unwrapped. Attached image of the UV (channel 0) of the object. I marked in red line the polygons of these black faces.

4

I have created the UV manually from Blender with 0.04 of margin between uvs islands and it looks like it looks better now.

Is a margin of 0.04 sufficient?

5

If some leaves have dark zones (image attached), because it can be? lightmap resolution too low (64)? margin between uvs islands too low?

6

I’m trying to optimize the UV lightmap and it’s frustating :frowning:

I think that the UV lightmap has few uvs islands now. But when I build the lighting the object has dark zones. I tested with lightmap resolution to 64, 128 and 256, and the result can be seen in the images :frowning:

screenshot_1: UV lightmap
screenshot_2_64: lightmap resolution 64
screenshot_2_128: lightmap resolution 128
screenshot_2_256: lightmap resolution 256

The size of the texture of the object is 32x32 pixels because it’s a solid color. I tested with a 2048x2048 pixels but the result it’s the same.

I am doing something wrong?

7

I tested it with 20x and 100x bigger, but the result it’s the same.