Serious problem with normal maps

[Rikk The Gaijin]

Hi, I don't know if this problem has been reported before, if so I apologize.
I don't know since when this issue is happening, I never really noticed it before, but I went back to version 1.0 and is still happening, so I guess it just went unnoticed.

Long story short, if I apply a normal map with power of 1 (which should be 100%) I get horrible black spot all over the place, it seems that when the range of brightness goes too high, Octane clips it out and make those areas black! If I reduce the power of the normal map to something very low, like 0.1, the black goes away, but obviously the normal map details are very weak.

Here some example, please note that this issue happens with any object, and any normal map.

Just for the sake of the test, I did the same render in Vray, and it comes out correctly.

[Rikk The Gaijin]

I forgot to say that I'm on a GeForce GTX 670
nVidia drivers ver. 314.22
tested on Octane version 1.0, 1.11, 1.12 and 1.13, it happens on all versions.

Any idea on why this is happening?

[Refracty]

Could it be that you use a 16 or 32 bit Normal map?
I had similar issues and converted my Normal map to 8 bit and then it worked like expected.
So check the bit depth.

[bicket]

I experience the same problem with normal map and bump maps on glossy materials.
I think it's a bug : dark edges on glossy materials.

here an example of dark edges on glossy mat with normal map

[kavorka]

I've been noticing this too, just thought I was doing it wrong

[César]

I agree, Rikk, and it seems to have the same dark artefacts with bump maps, I thought it was me too.

[manalokos]

I've noticed that since very early on when I got octane... but never thought it could be a bug... it is definetly a limitation....

[Rikk The Gaijin]

Could it be that you use a 16 or 32 bit Normal map?
I had similar issues and converted my Normal map to 8 bit and then it worked like expected.
So check the bit depth.

The normal maps I tried were all 8 bit.
Does anyone on the Octane team have a thought about this?

[roeland]

We have solved this problem a while ago for shading normals, but not yet for normal and bump maps. The problem occurs when the shading normal deviates too far from the face normal. For now you can only avoid this problem by avoiding too strong normal maps or by baking the bumps as geometry.

You shouldn't get different results if you use a 16-bit map vs an 8-bit map.

--
Roeland

[Rikk The Gaijin]

Ok, so it's a limitation of the current version. I look forward for the fix in the (hopefully not to distant) future.