On 2/19/26 19:18, Bald Eagle wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> 
>> I'll try perspective and maybe sturm when I get back in.
>> The really puzzling thing about it, is that all of the other tori render just
>> fine.
> 
> Changing to perspective helped - but there was still a thin line of cruft around
> the perimeter.
> Sturm didn't do much to remedy that, but shifting the camera up a little bit
> did.
> 
> The shadows still look weird.
> 
On the shadows.

First a disclaimer. In not completely understanding the geometry of your 
scene, seeing what you see as wrong about your shadows is not completely 
clear.

That said, one of the things which can happen is that the shadow test 
rays can resolve to surfaces different than do the camera rays.

For example, sometime last year I posted about the sor example used in 
our documentation being problematic for our solvers - especially those 
in the official POV-Ray releases. There were cases there where shadow 
test rays in some set ups were causing solver problems while those from 
the camera were OK.

I'll also mention the 2.5 issues in the shadow cache mechanism of 
official POV-Ray releases which are fixed in the yuqk fork. Those shadow 
cache issues can cause strange shadow artifacts - depending on 'stuff'.

I'm busy today, but I'll put on my todo list testing with your 
orthographic camera(*) and zoom set up. My generic orthographic camera 
set up is somewhat different.

Aside: An interesting test would be to replace the torus{} shapes with 
isosurface f_torus() shapes. The isosurface mechanism (so long as the 
max gradient is large enough for all ray approaches) is often more 
robust / stable with respect to resolving surfaces from varied ray 
approaches.

Bill P.

Post a reply to this message