Explanation of "normal map"

Raylectron (https://Raylectron.com) is a 3D rendering engine for Trimble Sketchup (https://sketchup.com)
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PreVision
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Joined: Fri May 17, 2013 9:19 pm

Explanation of "normal map"

Post by PreVision »

New user here--I have a general question about how the "normal map" is used--I looked elsewhere on the site and can't seem to find an explanation.

On other rendering programs I've used, there is often an option to load separate bump maps, specular maps, transparency maps, etc. but Raylectron just appears to have an option for a "normal map". The examples of these maps I see posted to the forum also show them to be somewhat rainbow colored rather than greyscale like other maps used in other rendering engines--is this significant?

I guess I'm just after a bit of a rundown of how the normal map is used, tips, limitations, etc. If this is already posted elsewhere, can you direct me to where it can be found.

Thanks,
Adam
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Support
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Re: Explanation of "normal map"

Post by Support »

The bluish rainbow normal map file is the best one to use because it contain the data of the surface orientation rather than elevation or fake bumps. Basically, a surface has a normal vector, for a flat surface, the normal vector is perpendicular to the face. The bluish normal map alter this normal vector to point into a new direction, and that is what makes it bumpy without changing the geometry.

We do not use other maps because...

specular maps are fake, Raylectron compute true Shininess instead.

transparency maps, Raylectron handle material transparency such as those from PNG images.

bump maps do not contain vector information, that's why they are gray. Normal maps used RGB values for the vector and that's why they appear bluish and are much better quality for bumps.
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Dknight
Posts: 92
Joined: Fri Aug 17, 2012 12:07 pm

Re: Explanation of "normal map"

Post by Dknight »

I've had some really good renders with normal maps.

There is a free plugin for photoshop so you can make them yourself too if you need to.

https://developer.nvidia.com/nvidia-tex ... -photoshop
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