"Correct" normal maps? Left handed and right handed normal maps?

[videl]

Hi

I was just wondering with which programs I get the same correct results when creating normal maps.

As far as I know by now, a normal map can either be right handed or left handed, depending on the green channel (and you can switch between the two tangent spaces by inverting the green channel).

I think (I am not sure) that I get left handed normal maps with the nvidia photoshop plugin from photos and right handed with xnormal from a highpoly mesh.

Is it true that I get different spaced normal maps with xnormal and the nvidia plugin? What ist more common, right or left handed?

regards
videl

[Steppenwolf]

Always depends which normal tangent the game uses that you do your textures/models for. If the green channel is wrong just invert it before you save the texture or before you mix them with normals from another program. It's not much hassle once you know how it's supposed to look correctly for your game.

I haven't heard the terms left or right handed normals. I always check if the "green light" comes from above or below. This for example is how its supposed to look for Source Engine and CryEngine:

[videl]

That's exactly what I mentioned with right or left handed tangent space.

So both ways are equally good, depending on the engine? We are writing the shaders for our game, so we can actually decide what we want to use. I think we will stay with left handed tangent spaced normal maps, in your example the right picture.

[Steppenwolf]

Quality wise it shouldn't make a difference which tangent you choose for your game engine. It's only important that your artists stick with it otherwise brightend and shadowed edges are inverted ingame which looks wrong.