Normal map generation overlapping

Normal map generation overlapping

Postby JamesLit » Tue Mar 08, 2016 3:34 pm

Hi all,

Have Googled this issue and read a thousand articles and sadly none have solved the problem. Suggestions were offered which altered the result but did not fix it.

I am trying to generate a normal map and the result has a lot of what I can only assume is overlapping. Any suggestions to fix this would be great. I have already tried the various cage alterations suggested, push modifiers, etc.

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Re: Normal map generation overlapping

Postby AndiS » Tue Mar 08, 2016 5:45 pm

No idea what a cage alteration would be in this context, but here we go. Not having a clue never stopped me having ideas.

Am I right in thinking that what you need is a few more bits between the texture islands? I only know this from the diffuse colour texture where colours run into each others when you get farther away because of the averaging this mipmap feature does? Now for a normal map, that certainly can have stupid results. Is that what you are talking about? If not, discard the rest of the post.

Solution 1: Tell the system to always use the maximum resolution texture for the normal maps. No idea how you do it for RW, but people do work with .dds and there is a flag "don't use mipmaps" in the DDS tools I came across (for Zusi, not RW).

Solution 2: Failing (2), create the mipmaps manually. For diffuse colour, there are guides out there. I would got for a texture that produces the default normal, i.e., just solid blue/violet, whatever, the colour that most of your image is made of. Taking that for all mipmap levels except the nearest one would at least stop the trouble, would it?

Solution 3: Get a headache. From the fact that you have one, I deduct that solutions 1 and 2 don't work. Solution 3 would be to shrink all the UV islands, both in the image and in the UV mapping. That would require a rather clever script to do. And assuming that you don't have the normal map in a monster resolution, you would get stupid rounding effects. So it might not be worth the effort.

Ok, now I am really curious what the problem is in fact. :lol:
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Re: Normal map generation overlapping

Postby Pauls » Tue Mar 08, 2016 7:01 pm

You can set the object spacing for automatic mapping and pixel borders (padding) when you set up the rendering in Rendering > Render to Texture

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Re: Normal map generation overlapping

Postby JamesLit » Tue Mar 08, 2016 10:19 pm

Thanks both for your suggestions but sadly none of them quite solve the problem!

As before, it changes the result, sometimes improving it, but still not actually fully addressing the problem.
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Re: Normal map generation overlapping

Postby Pauls » Wed Mar 09, 2016 2:10 am

Perhaps having done the automatic unwrap you could manually move and resize the various faces ?

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Re: Normal map generation overlapping

Postby JamesLit » Wed Mar 09, 2016 8:27 pm

Pauls wrote:Perhaps having done the automatic unwrap you could manually move and resize the various faces ?

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Presumably that cannot be done in such a way that affects only the normal map, and not any other textures?
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Re: Normal map generation overlapping

Postby AndiS » Wed Mar 09, 2016 10:37 pm

At least in Blender, you can have more than one UV map. You certainly can in 3DSMax, if that is what you are using. However, it is an obscure feature to many, so it may well be hidden somewhere.

With some luck, you could even copy the UV map as a starting point.
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Re: Normal map generation overlapping

Postby FastlineSimulation » Thu Mar 10, 2016 3:42 pm

JamesLit wrote:
Pauls wrote:Perhaps having done the automatic unwrap you could manually move and resize the various faces ?

Cheers
Paul


Presumably that cannot be done in such a way that affects only the normal map, and not any other textures?


You can have a different UVW map for every slot available in the shader that you are using. You'll need to use UVW channels which can be set when you apply the Unwrap UVW modifer.

This post gives a good starting point: http://the-art-of-rws.blogspot.co.uk/2010/01/kuju-materials-and-shaders.html
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Re: Normal map generation overlapping

Postby JamesLit » Thu Mar 10, 2016 10:18 pm

Strangely, even moving things around on the UV map seems to do the same as most other things - it alters the result, sometimes improving it, but does not solve the problem... really don't know what else to try!
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Re: Normal map generation overlapping

Postby FastlineSimulation » Fri Mar 11, 2016 7:26 am

Are you using the default scanline renderer or mental ray for the actual rendering?
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