Am 09.12.2016 um 03:36 schrieb Mike Horvath:
> If I rotate the camera 90 degrees around the x axis, the isosurface
> disappears.

My guess would be that on the "bottom" side of the shape, the function
has a much stronger gradient, so that when POV-Ray starts searching the
contained_by volume for intersection points starting from that side, it
finds incredibly huge values and thinks, "oh, I must still be VERY far
from the surface" -- advances a good deal, _skipping_ over the actual
body of the shape, and finds itself still outside, concluding that there
is no shape at all.

You must either increase max_gradient to fit even that portion of the
shape, or somehow find a way to get a nicer gradient down there.

Post a reply to this message