Normal mapping question

[Nysuatro]

I think its your cage
Put shaded on and adjust your cage

[Marcel]

It's hard to say anything without seeing the low and highpoly objects. :)

[Yinn]

Well, here they are, shown in melody :3
http://img.photobucket.com/albums/v311/Yin22/melody.jpg

It's not the cage though, I've been messing around with it a lot but not had any changes. I don't see why it works so perfectly with object space and not with tangent space. Tangent space does support this kind of roundening(making a low poly cylinder appear high poly and smooth) right? Or is that something you lose because it's supposed to be deformable...?

[[Sanaloria]Snake]

This can be explained by the different type of normal maps. Look here :

http://www.codeproject.com/cs/media/NormalMapCompressor/NormalMapCompressor.jpg

This is a tangent map. The main color is blue, which represents the normal of the lo poly model, because it roughly has the shape of the HiPoly one. This blue is coded (128 128 255) in RGB with means Z+ in XYZ coords, this is the normal that cames toward you (points out from your screen to finally touch your nose ;) ). This is why an tangent space map is mainly blue :D. If I could see a better picture of your tangent map (I mean, higher resolution, 256*256 should be enough), I could tell you if the map is ok, but as far as I can see, it looks ok ! This looks like a good tangent space normal map.

=> make a test ! take the eyedropper in photoshop. All along the same line of pixels, control the color : it may oscillate very slightly as the difference of geometry between the Hi an Lo poly versions implies difference of smoothness (and then difference of normal orientation and then difference of color in the normal map). An easier test is to make a very low poly version :
- make a tube that has 24 segments
- make a tube that has only 6 ones (hexagonal section)

=> make the normal map, you will notice 6 quadrangles in your normal map with a gradient, going from a pink color to blue and then to a more purple one, then it suddenly restarts with the pink etc (assuming that the axis of the tube is along the V axis in the UVmap, like your pot).

The object space means you may have normals pointing in every direction possible, this is why you have plenty of colors (360° horizontally+360°vertically which means 4*Pi). In tangent space, you just represent 180° vertically + 180° horizontally (2*Pi).

Is that clear ? (I know that's confusing :) )

[Yinn]

Oh! I see how it works now. I also tried the cylinder thing. That makes it quite clearer, yes. Thanks a lot for taking time to explain. :)

[[Sanaloria]Snake]

No problem :thumbsup:

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