looks like vray wont read negative values in a dispmap if i use a composite node to combine two maps…
disp_test.rar here the maya file…
image_39003.rar (4.64 MB)
Try setting explicit displacement bounds in the “Displacement control” extra attributes to the displacement node. When the texture is not directly passed from a file but goes through other nodes (incl. if it’s a sequence or uses texture tile tags like UDIM/UVTILE) V-Ray is not able to automatically compute the bounds and it’s necessary to set them explicitly especially when there’s negative values. Try settings something like -5 to +5 and see if it helps. Btw, since Maya 2016 (I think) the HSV color picker does not allow negative values, so you’ll need to switch to RGB 0-1 and set the negative minimum value for R, G and B.
thanks that does work…