I’m having trouble controling the gamma of say monochrome maps for bumps to apply gamma 1.0 to them. I tend to use a script to apply auto-gamma to all maps but wanted to control the gamma through the color correct modifier for the the bump slot for example. As using G1.0 for monochrome maps leads to better results, it would be nice to control this with an external map.
See results. Beauty pass is fine but the corrected gamma has no effect on the Normal shading pass.
I just checked this. You do not need to see the element, you can see the effect on beauty. It behaves the same way with MR - it is impossible to alter bump using CC or Output node. So it looks like a Max limitation, but maybe it is possible to hack it?
However, you can always (also in Corona) alter a normal map using CC or Output.
I tried using the Corona Normal modifier map and checked the box for adding gamma but this was not a great result. I’ll try see if I can add a curve to the output map to replicate the 1.0 gamma. I post back later my result.
The Corona Bitmap Map could have a checkbox to do the same and have a gamma spinner in there too which would be great. Better solution to controlling gamma than the loader method.
I think someone on here suggested better color mapping but was shot down by Ondra. Found it:
But this would be different as it’ll act like the VrayColor2Bump in the sense it’ll be two maps combined in one. Maybe Ondra might change his opinion on this. ;]
No amount of tweaking the curve in an output map has any effect on the bump slot. The displace however is different and reflects any tweaking in an output map and a CC map. This has to be a 3ds max bug.
Here’s just a simple comparison between 2.2 and 1.0 gamma on their own. The same bump value is used (50) in each. As you can see it’s a huge comparison. The map I’m using has 128 grey background and full black and white values on the text.
Diffuse is left at auto like normal in the example, just the bump gammas are changed to show the comparison.
Shall I post on mantis or request feature, what do you guys think?
Please try the same with the ColorCorrect Map from Cuneyt Ozdas (get the link from maxplugins.de), I seem to remember this worked fine there.
AFAIR the underlying problem is that color and bump are handled independently through different channels and maps that are designed to do color transforms will work only on the color channel and dismiss bump. Hence the bump amount paramter in the maps output controls, that’s the only one affecting bump. It would be great if this would be finally changed but then again they should update and improve the whole output/CC section.
Why does even 3dsMax come into equation ? It’s Corona shader after all. Bit confused by this. I could understand it would be possible limitation of 3dsMax Bitmap loader, but bump mapping which is Renderer’s property ?
Thanks for the suggestion. I did try that before. See screenshots of proof.
The relief on the white values differs greatly from the black values if you notice using 2.2 gamma. Should this not be the same regardless of how 3ds max interprets a bump bitmap? These values are opposite ends on the scale. But it’s probably due to the fact the 128,128,128 RGB grey value is getting shifted.
Anyway nothing seems to work with changing the gamma outside of overriding in the loader. Which is a horrible way to control it.
I agree Juraj. Just because this problem lies in VRay, mental ray etc doesn’t necessarily need to be the case with the Corona Shader.
So no implementation of Help could be added to the Corona Bitmap map?
This would allow us script something like:
theCoronaBitmaps = (getClassInstances CoronaBitmap)
for m in theCoronaBitmaps where m.gammaMapValue != 1.0 then (
for m in theCoronaBitmaps do (
m.gamma = -1.0
) -- set to auto gamma
)
gammaMapValue is just a made up variable
This would change any bitmap where gammaMapValue value is not 1.0 to auto gamma.
This way you could easily manage the value outside of the loader method which sucks.
well… you would think that would work, but what if you have 2 different bitmaps with different gammas in one slot? What if one of the maps is also in diffuse slot where you want it with different gamma?
So if I use a script like in the above post it’ll ignore and maps where the gamma spinner value in the corona bitmap == to 1. so you can’t possibly mess up anything. Maybe I didn’t understand you correctly. ;] And if you want different gamma then on the same bitmap then you simply copy that and change the gamma in the spinner. This way you always keep loading the bitmaps as auto gamma and change it after the fact which in turn will change the maxes loader value.
I don’t know why Autodesk implemented the gamma overrides where they did anyway tbh. They’d be better off placed in the bitmap map.
I just think having some sort of gamma control in the Corona Bitmap would be a great asset to have. Not sure if that’s something you would like to implement though?
