POV-Ray : Newsgroups : povray.binaries.animations : Mysterious vanishing isosurface : Re: Mysterious vanishing isosurface Server Time: 26 Feb 2021 21:45:24 GMT
  Re: Mysterious vanishing isosurface  
From: Mike Horvath
Date: 9 Dec 2016 13:25:46
On 12/9/2016 12:02 AM, clipka wrote:
> 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.
>

What's weird is that the "missing" area perfectly fits the dimensions of 
the bottom face of the cube used in the contained_by clause.

Anyway, I tried max_gradient 1000, and am now trying 10000. Not usre how 
long it will take however.

:(

Mike


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