Normal Maps and Bump Maps in V-Ray 5 for Cinema 4D

[JeremyLondonMDL]

I've got a few issues / questions about normal maps and bump maps in V-Ray 5.

1) I can't see an option inside the V-Ray material to flip the red and green channels of normal maps, as per the V-Ray Standard Material in 3.7. Do these tick-boxes still exist somewhere? Other options I've come up with so far include (1) set the normal map colour profile to Linear, place it inside a C4D Filter shader, activate Gradation Curves, and reverse the slope of the Red or Green curve, or (2) Manually create a flipped version of the normal map in Photoshop by inverting the red or green channel. These two methods produce visibly different results, so I'm interested to know what the recommended method is now.

2) Black & white bump maps seem to be inverted in V-Ray 5, i.e black = high, white = low, and there doesn't appear to be an Invert option. Is this as intended? So far the best way I've found to invert my bump maps inside C4D is to load them into a C4D Filter shader, enable the Gradation Curves, and reverse the slope of the RGB curve.

3) With Bump Type set to Normal Map in Tangent Space, the Bump Amount value appears correct if the Project Scale is Centimetres, but when the Project Scale is Metres the Bump Amount needs to be multiplied x 100 to get the same visual result (eg. 0.005m needs to be increased to 0.5m). When Bump Type is set to Bump Map (and a black & white bump map is used), this doesn't occur - a bump amount of 0.005m renders the same, regardless of whether the project scale is Centimetres or Metres. Is this normal / expected behavior, or am I doing something wrong?

Thanks in advance for your feedback.

[sirio76]

1- I’m pretty sure that if you load the normal map inside a Vray normal map shader you should be able to flip color channels
2- no need to use filter shader, just set a negative value or invert the 1-0 values inside the black/white point of the image

[aleksandar.kasabov]

Hello JeremyLondonMDL,

1) I can't see an option inside the V-Ray material to flip the red and green channels of normal maps, as per the V-Ray Standard Material in 3.7. Do these tick-boxes still exist somewhere? Other options I've come up with so far include (1) set the normal map colour profile to Linear, place it inside a C4D Filter shader, activate Gradation Curves, and reverse the slope of the Red or Green curve, or (2) Manually create a flipped version of the normal map in Photoshop by inverting the red or green channel. These two methods produce visibly different results, so I'm interested to know what the recommended method is now.

You can load your normal map through the VRayNormalMap shader. You will then be able to flip the red and green channels. You can find more information about VRayNormalMap here.

2) Black & white bump maps seem to be inverted in V-Ray 5, i.e black = high, white = low, and there doesn't appear to be an Invert option. Is this as intended? So far the best way I've found to invert my bump maps inside C4D is to load them into a C4D Filter shader, enable the Gradation Curves, and reverse the slope of the RGB curve.

As sirio76 mentioned, you can use negative values if you wish to switch the highs and lows.

3) With Bump Type set to Normal Map in Tangent Space, the Bump Amount value appears correct if the Project Scale is Centimetres, but when the Project Scale is Metres the Bump Amount needs to be multiplied x 100 to get the same visual result (eg. 0.005m needs to be increased to 0.5m). When Bump Type is set to Bump Map (and a black & white bump map is used), this doesn't occur - a bump amount of 0.005m renders the same, regardless of whether the project scale is Centimetres or Metres. Is this normal / expected behavior, or am I doing something wrong?

Upon testing on my end, I didn't see any differences when changing the Project Scale. Could you send us some screenshots demonstrating the issue? Also, it would be helpful if you can share a test scene. Thank you.