I tried every solution I know of ; baked with the a cage and without it , used different uv maps , deferent baking settings , applied all transforms , used non color image , 32 bit , used 8k image . and same result every time .
and I also noticed the baking is so fast ; it use to take 2min to bake one 4k normal map ,now it bakes in seconds and its lower quality .
do anyone know the solution I would really appreciate the help
Yes, sharp edges do appear in normal maps. This is expected behavior and it happens in all 3D software to my knowledge.
The usual solution in most cases is to have the low-poly model entirely shaded smooth and let the normal map deal with the shading (so the model will look incorrect when it’s untextured, but the normal map is going to fully compensate for the shading and make the model look like the high-poly version).
For the baking speed, it’s based on the number of rendering samples you have in your render settings. Blender’s baking system doesn’t support anti-aliasing, so a normal map baked with 1000 samples will look the same as one baked with 1 sample, so don’t bother using lots of samples, the quality is determined entirely by your image’s resolution.
When you mean Cycles is not casting enough rays, are you talking about these pixelated edges?
If yes, that’s a problem caused by Blender not supporting anti-aliasing / multiple samples in normal map bakes. Even if you use multiple samples, they are all sent to the same spot of the pixel, so it doesn’t make a difference.
This can be improved by baking the normal map at double (or better, triple) resolution and then shrinking it back in an image editing program. This manually fakes anti-aliasing by allowing more than 1 sample per pixel.
An other alternative is to do the bake in an external program which supports this feature. Usually, texturing programs like substance can do it. Or, for a free option, Xnormal, which is a little free app just for baking textures.
