Normal map/cage problem

[Piflik]

The problem are coplanar faces between the Highpoly and Lowpoly. I don't know why, but they do pose a problem...at least for Max' RTT. Apply a Push Modifier with minimal Value to the Highpoly (~ -0.001), or try a different program for normal map baking, e.g. xNormal (http://www.xnormal.net/1.aspx).

[biggestkid]

Ok im guessing the very minimal value is so its not visible in the actual model?

Also, could you please explain co-planar, i like to understand the concepts im working with lol? And thanks for the quick reply Piflik.

[Piflik]

Coplanar Faces are Faces that occupy the exact same space (for example two simple Planes, both at z=0). Those Faces are constantly fighting each other for visibility (depending on your Z-Buffer these fights can also occur for faces that are not coplanar, but very close to each other).

When baking normal maps, each ray has to decide if it is seeing the Highpoly or the Lowpoly, if there are coplanar Faces, so there are errors (although it doesn't really make much sense, since the ray wouldn't have to see the Lowpoly at all...AFAIK, it would only need the cage and the Highpoly to bake normal maps...but how would I know...I started Normal Map Baking about a week ago ;)...however, experiments show that it works with the Push Modifier and errors without...).

You would want to keep the Push value small, since you don't want too much difference between the Highpoly and the baked Map.

If you want more information on Normal Maps and Lowpoly modeling, you could visit some of the Game Artists' boards like Polycount.net, Nextgenhardsurface.com or the CGSociety-sponsored Game-Artists.net.

[biggestkid]

Yeah im on polycount but the replies there are very slow, limited and not very useful as i dont have as much technical knowledge, so i then have to spend another week finding out what they meant.

But anyway back on topic. Your push idea worked on the rails of my rail gun, but now ive got another problem on the handle of the gun. I think its coz of missing poly's or something. Im 99% sure its not the co-planar faces any more. This is because when i did the push it eliminated a lot of the red, but now there is just little odd spots of red.

Here is a pic of the render-to-texture.
http://img196.imageshack.us/img196/3244/newrendertotexture.th.png (http://img196.imageshack.us/i/newrendertotexture.png/)
(Click to enlarge)

Can you give me any ideas on how to fix this?

Thanks for all the help btw Piflik.

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