1.4.2.8 Isosurface not rendering properly?
"My isosurface is not rendering properly: there are holes or random noise or big parts or even the whole
isosurface just disappears."
The most common reason for these type of phenomena with isosurfaces is a too low max_gradient value.
Use evaluate to make POVRay calculate a proper max_gradient for the isosurface (remember to
specify a sensible max_gradient even when you use evaluate or else the result may not be
correct).
Sometimes a too high accuracy value can also cause problems even when the max_gradient is
ok. If playing with the latter does not seem to help, try also lowering the accuracy .
Remember that specifying a max_gradient which is too high for an isosurface, although it gives the
correct result, is needlessly slow, so you should always calculate the proper max_gradient for each
isosurface you make.
Note that there are certain pathological functions where no max_gradient or accuracy will
help. These functions usually have discontinuities or similar "illbehaving" properties. With those you just
have to find a solution which gives the best quality/speed tradeoff. Isosurfaces work best with functions which give
smooth surfaces.
