vray displacement -relative to bbox?

[super gnu]

this button isnt covered in the spot3d help page.. i was wondering if someone can explain its effect? it seems to increase the displacement amount.


my guess:

normally, the disp amount is relative to an ideal black and white disp. map, where the amount value will only be achieved if your lowest point is black and highest white.
with relative to bbox is ticked, it makes the amount relative to the brightest and darkest portions of your map (i.e. your maximum disp. depth -will- be the amount value even if your map contains no pure black or white..)

does that sound correct? ive gotta teach this stuff... lol.

[vlado]

This is actually a 3ds Max thing; when this option is enabled, the maximum displacement amount is tied to the size of the object's bounding box. So if you apply the same map to objects with different sizes, the smaller object will be displaced less. This is how the default 3ds Max displacement works.

Unfortunately this breaks down if you have deforming objects, where the bounding box changes from frame to frame. Which is why V-Ray allows you to turn off this behavior and instead specify the displacement in absolute scene units.

Best regards,
Vlado

[super gnu]

ok thanks.. i liked my explanation, but yours is good too