Answered: DDO to Redshift roughness problem

DigitalMechanik

Hello, I used the Metalness disney exporter in DDO and connected the maps to redshift in Maya. Here ist the result. The main problem I have right now, is that the roughness doesn't seem to be the same. I set the colorspace to raw, alpha is luminance and BRDF is GGX. Do you have any idea what is wrong? By the way its the same HDRI.

Synaesthesia

I honestly have no idea. I work with game engines primarily, not with offline renderers. I'll have our in-house artist Billy take a look at this - he's significantly more experienced in offline rendering than I am.

Billy Lundevall

Hello. The reason you are seeing a difference is because DDO does not display a GGX roughness profile properly. Setting your project as "Specular GGX" doesn't change the appearance in the viewport at all compared to "Specular Default" and your are left with an offset between what you see in the Suite vs what you get in your render package. Using Arnold, I get around this by setting my "alpha offset"  option to something around -0.25.

DigitalMechanik

Thank you.
nIf I set the "alpha offset" in maya to -0,25 it gets even more shiny. so I guess you meant +0,25? Thats the result and I think its pretty close:

I only have to do change the alpha offset for the roughness map right?

Also I had to change the domelight exposure to 0 instead of 1 otherwise I get clipping highlights. But now The asphalt ist too dark. Is the dynamic range of the maya camera lower than 3DO's or is this something else?

Is there anything else you can think of that I have to change to get the most matching result? I set every grayscale map to raw and "alpha is luminance" and the albedo map to srgb.

Billy Lundevall

I am very new to Redshift, I have only rendered on thing in it so far but I got a very close match on all other maps, so sadly I don't have much more input in this. The model I used was the reflection + edge tint workflow which worked nicely with a diffuse + specular map, leaving the edge tint as is. The light intensity will of coarse change the perceived brightness of your material, and if you are using the same HDRI in both Maya and 3DO the intensity should be left at 1. I tend to use camera exposure as a brightness controller instead of changing the intensity of HDRIs, making them brighter in particular can cause very odd behavior.

And no, I actually usually use -0.25, but that is in Arnold. So it may differ. The roughness is the only part I need to tweak there.

DigitalMechanik

The light intensity will of coarse change the perceived brightness of your material

I am not sure if you got me right. If I set the HDRI to 1 the asphalt looks fine but the metal part is too bright and therefore clipping. So my only explanation is that the dynamic range of the camera is different in 3DO. Like in real world cameras. But maybe this isn't even a think in the 3D world. This is how it looks with HDRI exposure back to 1. The Asphalt is more like in 3DO but the metal is clipping.



Can you tell me more about your edge tint workflow? Which export preset did you use? Do you only connect the diffuse and specular map? Really appreciate your help