Normal Map Confusion (images Included)

Trevor

Over the last couple of months I have been learning the basics of 3d modeling and im stuck on Normal maps. Im trying to figure out the high to low poly workflow as im making a gravestone but the normal map is a giant obstacle for me :poly127:.
I am running into problems with my normal maps at every turn. Im getting extremely different rendering results in different programs with the same normal map.

My confusion stems from the rectangular part of my normal map where there is a noticable color transition in the center of what is supposed to be a flat surface. This confusion doubles when I look at the results in Blenders render and Mudboxes render. Blenders looks just fine but Mudboxes looks aweful.

Im positive that is has something to do with my geometry but I dont know where the problem is. Are there too few polygons? Adding control loops on the low poly seems to make the problem worse by skewing the normal map. Is my geometry too dirty and uneven?

Im really lost here so any help would be amazing!

Quack!

The green channel looks inverted in the Mudbox screen.

Those large gradients in the normal map are occurring because your low poly has little detail. When you have edges at 90 degrees on 1 uv island, the normal is generated to compensate in game for that. As long as it looks good in your engine of choice, it is ok. If you are getting issues with mipping and / or artifacts, you can add chamfers at your hard angles to give ease the normal map. You could also break your uv's at those hard edges on the uv island and smoothing groups. I prefer to add the small chamfer as it is similarly cost efficient most of the time and adds detail to the model.

Trevor

Thanks For the tips ill give them a shot. You also inadvertently answered a question I had about Mudbox, which was the inversion of channels.

Thanks Quack!!