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trs79

normal map not smooth, hard edges in shading

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trs79    126
Hi All,

I'm trying to use transfer maps in Maya and a simple test case with a low-res cylinder and high-res cylinder. However, when I generate the tangent normal map it comes out flat, i.e. all one shade of purple, see here:

[img]http://img836.imageshack.us/img836/9286/cccnormal.gif[/img]

I would expect to see some smooth gradient or something else. When I render in Maya you can see the edges on the low poly model (I added an arrow in photoshop). On the left is the high poly cylinder.

[img]http://img715.imageshack.us/img715/2293/ccccccct.jpg[/img]
the edges look like slight white-ish lines. I've noticed that phong shading in general shows some trace of hard edges, I assume that's due to the interpolated normals? However with the right normal map shouldn't it be possible to eliminate those hard edges in the shading, i.e. my understanding is something like this is possible(from bencloward.com):

[img]http://www.bencloward.com/images/tutorial_normals34.gif[/img]

Thanks for any help.

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Burnt_Fyr    1665
I would expect that a cylinder would have a normal map exactly as the one you posted, as at every point on the surface, the normal is pointing directly out from said surface. how are your UV's being applied along the cylinder?

I'm not sure if this exists in the original, but in ms paint I'm getting a black line across the top row of pixels.

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rouncer    294
that normal map is just pointing forwards at every pixel, that wouldnt result in any output even if you did the whole thing right, thats poor data.

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trs79    126
Thanks all for the replies.

@rouncer:
Ok that confirms my suspicion that the normal map wasn't having any effect

@Burnt_Fyr:
That makes sense for the low-poly cylinder by itself, but I thought in relation to the high poly cylinder shouldn't there be a gradient-like normal map since the high poly mesh will have a much "rounder" surface then the low poly? Below is a uv snapshot of the uv layout:

[url="http://img709.imageshack.us/i/uvs.gif/"][img]http://img709.imageshack.us/img709/3383/uvs.gif[/img][/url]

Uploaded with [url="http://imageshack.us"]ImageShack.us[/url]

About the black line in MS Paint, that is odd but I don't see it on my end. I appreciate the help, do I need to reorganize the uv's to get the normal map generation process to work as expected?

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