Arnold Render issue

ozzy310

I'm new using Arnold and still learning how to use it. Everytime im doing a single render image on the oil drum I get an issue where the normal does not look good, it seems inverted like 3 and sharp shadows or reflection 1, 2. In the viewport 4 it looks fine but not when rendering. Im using aistandard surface shader, in bump2d tangent space normal is set, under arnold I flip both R and G channels with different results but none that I want. R channel result is 1, G channel result 2. Also, Color space is set to RAW. Im beginning to suspect is just the normal and it just a bad bake. Unless, there is something missing im not aware. Any help will be appreciated, thank you. 

sprunghunt

If you're rendering something I wouldn't use normalmaps like this. I'd just make a hipoly subdiv version of the barrel with about 10k polys in it.

Eric Chadwick

Agree.

Why you're seeing this problem... Normal maps are baked using something called a Tangent Basis. If the renderer doesn't use the same basis, you'll get lighting errors.

http://wiki.polycount.com/wiki/Normal_Map_Technical_Details#Tangent_Basis

Eric Chadwick

Also, in the future it will help you if you indicate the 3d software you're using, in the title. 

e.g. Maya and Max use different material setups for Arnold, so knowing which software matters for the answer.