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Freemorpheme

Seam on baked normal map

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After I posted this last question:

 

...I went away and unwrapped my blood cell to try to bake the texture and export as an fbx.

 

I had some success, but the normal map created is picking up the seam of the UV in a weird way. This is the first time I have done this, I have no real idea how it is supposed to work so if anyone could explain like I'm 5 how baking and reimporting a texture would ideally work I would be grateful. Have I unwrapped the cell in the best way?

 

Here is the file:

 

https://we.tl/t-WrWV00XhCK

 

Thanks, I have moved this over from Texturing as it is clearly more of a basic question.

cdew.jpg

Screen Shot 2018-10-09 at 13.21.26.png

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Looking at your scene file, there are these things I'd like to mention:

- About the seams in general
Before baking textures it's necessary to think about the so called pixel border (in some applications called padding).
In the texture baking dialog the default value for the pixel border is set to 1. This might be enough if the texture output size is 256x256 (default).
But if your desired texture output size is 1024 x 1024 pixel, it's necessary to increase the pixel border value to e.g. 10.

This fixes the seams issue by creating an additional, stretched to 10 pixel width, texture data padding around the UV islands.

Always provided there is enough free space which can be used on the output texture map.

The areas marked with red arrows are showing some UV polygons touching the edge of the UV space, or some are very close to the edge.
This is not good, even the largest pixel border setting can't solve this. All texture data for this areas captured by the baking process will be ignored and this might cause some texture mapping trouble. So just move the UV islands slightly away from the UV space border, increase the pixel border value and bake again to solve this.

Btw.: The Supersampling setting in the baking dialog can help to improve the output quality (Anti Aliasing) of the generated texture map(s).

Unfortunately it also dramatically increases the processing time. If your output texture map looks pretty jagged, set the Supersampling value e.g. to 2 and compare the results.

Or just choose a much higher resolution for the output file, manually optimize these areas in Photoshop and scale the whole thing down at the end.

- About the normal map
As far as I know, the normal map baking requires a second, higher resolution mesh, to capture those surface details you wanna bake.

Since I don't have access to a computer with R19 at the moment (I'm still on R12 and its baking options are unfortunately absolut outdated), I have to guess for the right baking settings. Must be something like this: for the output texture options: "Normal" checked, usually a source mesh has to be defined, and in most cases "Tangent space" for output has to be activated.

- About the UV layout: I do not see the need to cut the mesh in this "pacman style". A simple loop cut to get two "donut halves" would be enough.

illustration:   https://i.imgur.com/58QekJ6.jpg

Hope this helps

 

 

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  • Topic Author
  • Thanks for your help, I have had time to look at this again. I will change the pixel border, this is good info. But I cant see a way to unwrap this mesh into two halves without the 'pacman' shape, if I make a loop and try to relax it then C4D just makes the pacman shape anyway.  UV edit is not the most intuitive part of Cinema, can anyone else unwrap this successfully?

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