V-ray maya ptex displacement only partially working

[dre4mer]

Hi there,

If I can get this figured out properly I will write a nice tutorial detailing how to do it for everyone. However, I have a little problem I can't figure out. Below is a screen shot which should give you a lot of information as to what might be happening. I am using a 32bit floating ptex displacement file exported from mudbox 2014 in a displacement node on a vraymtl in maya. It's working. But as you can see from the Mudbox image on the right side to the V-ray Maya render, some amount of the detail is lost or "filled in" so it's only kind of working. Anyone know what might be causing this issue?

Thank you so much for any help!!



-Ethan

[Morbid Angel]

I think this means that the negative values are being clipped off. There is a few things you can check. In your displacement where the clipping bounds are set to auto, can you see if you set them to explicit and set the value to be -1/1 or whatever your highest / lowest displacement is. If that doesn't work, check if there is allow shader negative color checked in misc ui, in render globals.

[dre4mer]

THANK YOU! Setting the displacement node displacement bounds to "explicit" and then min value to -1 in the V did the trick! It looks to be performing correctly now. I wonder why the "auto" didn't work though.... this kinda thing makes these things difficult for some people to figure out and decreases the plug and play ability of v-ray.

[Morbid Angel]

Auto won't work. To get automatic bounds you need to first search the entire image to get the values of min max. But like mipmapped image, ptex is vertex based so I don't think it will be possible to get the automatic bound from it.