William F Pokorny <ano### [at] anonymousorg> wrote:

Thanks for the reply.

> I don't have a lot of experience with parametric surfaces, but I've
> found with them and some other of Pov-Ray's mathematical surfaces that
> there can be issues when the rays from the camera more or less line up
> on the axis of the mathematical axis there can be noise. I've seen this
> in more complex prisms too for example.
>
> Looks like your camera is offset some so a quick test as to whether you
> are hitting calculation noise is to try an orthographic camera by adding
> the word orhographic as the first line of your camera definition. You
> probably won't want this camera type for your final render, but if it
> cleans things up, it gives the strong hint cleaner results are possible
> by positioning your camera more off axis relative to the problem parts
> of the object. If orthographic works, with the default camera maybe go
> to a height of 1.5*height in z. Or a change to the parametric object
> itself might help if it makes the problem camera ray to object
> relationship less orthogonal.

With the orthographic camera, there is still visible noise. However, what bugged
me the most was the "slice" through the middle floor of
  https://i.imgur.com/p7ZkDTZ.png
and that could be mitigated with the orthographic camera and, indeed, by
changing the z-axis offset of the camera. So yeah, of course it's not completely
optimal but for my purposes, this should be fine; thanks.

> Other things I see. You've got a couple pigment+finish definitions on
> sub objects of the whole. This can be done if one is careful not to
> create competition between them. It would be more normal to have one
> texture in the final union/object.

Makes sense. For the pigment ones, I need to apply different ones to the ramps
and the disks; if I put the "filter" from the disks on the ramps, they turn
grainy -- is there a way to fix that?

Post a reply to this message