HQV and Normal maps

[bottleofram]

Heres a screenshot of an object and a normal map from zBrush in HQV:


And heres a mray render:


As you can see, HQV is displaying normal maps inverted. Anyone has an idea why is this?

EDIT: normalmap node settings used:

[Hirazi Blue]

There is a warning of sorts concerning Normal Maps in the User's Guide:

Bump maps, normal maps, and anisotropic effects do not appear exactly as in the rendered image because of differences in the way the basis is calculated. The discrepancy may increase with longer chains of connected shaders.

(Quoted from here)
Not sure if that helps, though...

[bottleofram]

Ok, this happens because you need to flip the red channel in order for this setup with the tangent map to work.
Tried with ultimapper, and confirmed.

I must admit, my knowledge in this area is really low, but as far as i know, this is the only method to properly render normal maps with no visible seams in XSI (and mray). You would expect it to work with HQV as well.

[j3st3r]

In my experience it depends what you are using for normal map calculation.

In many cases, I used to use flip the Y channel of the normal map, and it works perfectly. In your case it looks like that's the case also. As you might know, normal map defines the normal of the rendered pixel (more precisely the texel) if I'm not wrong. Try flipping the Y channel.

[bottleofram]

You are right. Flipped green displays properly in the HQV but it doesnt render that way, while flipped red does the opposite.

So.... humm...