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Decal Normals casting wrong/weird shadows

Posted: Wed Apr 15, 2020 8:29 pm
by ChaosLasse
Hello Guy,
so my problem is that the normals i made for some decals seem to look inverted or look like the light hits it from a mirrored sun vector.

Basically the shadows are flipt 180° so that the peeks look like crevices...

I got the tire marks by flipping the normals in Blender. So the peeks are now crevices and the crevices are now peeks.

When i did that to the other normal, it take the light on the flat surfice weid, when i rotate it, even the flat survice darkens, like there is a shadow getting casted.

I took a look at other normals of decals from differend creators, all have this problem an my track for some reason.

The original High Poly in Blender
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The Decal with the intended normal Map (light from the left)
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Light from the bottom left
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The tire marks
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has someone any idea?

Thanks in advance

Re: Decal Normals casting wrong/weird shadows

Posted: Thu Apr 16, 2020 1:18 am
by jlv
Try exporting a sphere to start with. The normal map should be around 128,0,128 at the top of the sphere, 255,128,128 at the left, 128,255,128 at the center, 0, 128,128 at the right, and 128,255,128 at the bottom. Flip whichever channels you have to to get the right values. Once you have a sphere working other things should export without any problems.

Re: Decal Normals casting wrong/weird shadows

Posted: Thu Apr 16, 2020 2:04 am
by aeffertz
Bake your norms as you normally would (don't invert the model).

Once you have your normal map baked from Blender, open that normal map in Photoshop (or equivalent) and invert the Red and Green Channels. Save the normal map and now it is ready to go in game and should not look inverted.

Re: Decal Normals casting wrong/weird shadows

Posted: Thu Apr 16, 2020 7:58 am
by ChaosLasse
Thank you guys,

jep, inverting the channels did the trick, thanks again. :D