Mirror reflections and anti-aliasing question

nowefg

When rendering a scene with a mirror, the reflection in the mirror renders as if it's not anti-aliasing, (if that's the correct term when the outlines of all objects in the reflection are jagged, not matching the actual outlines of the reflected objects in the main scene.) Since the primary objects being reflected in the foreground render perfectly, I'm unsure about what parameters need changing to get the reflections to match.

Any ideas?

nowefg

Hi,

Using 4.6, 3Delight. I keep forgetting to ask this question, which I did post on Nuts-N-Bolts earlier:

Whenever I render a scene with a mirror in it, the reflections in the mirror show very jagged edges, while the main objects being reflected in the main scene render perfectly. No idea, then, what parameter or other needs adjustment to get the reflections to match the main scene object resolution (or anti-aliasing or whatever it's called.)

The upshot of this is I don't render scenes with mirrors, but better to get it figured out, eh? Does anyone have an idea about how to get accurate reflections to render in 3Delight?

Richard Haseltine

Merged threads.

Is your Shading rate, in Render Settings, still set to the default value of 1? Reflections (and specular highlights) are more sensitive to shading rate than direct rendering, so it is usually necessary to lower the value. Try .5, and if that fails .2. If even .2 doesn't give smooth results please post a screenshot of your render settings here.

nowefg

Thanks, Richard,

I'll try that lower rate, and post if needed.

mjc1016

Also for reflections,  you may need to increase the pixel samples slightly...if the default is 4, take it to 6.  If you are using the default sinc filter the 4 to 6 range is fine for most things (DoF being an exception). 

nowefg

Thanks, Richard and mjc1016,

Pixel samples is set to 24, my usual setting...

I tried shader rate as low as .1 with little appreciable improvement, but, I also tried changing the filter from sinc to box, and that cleared up most all of the difficulty. Something to do with my specific graphics card, perhaps.

In any case, much better renders, now. Thanks for the responses.

mjc1016

Unless you are doing a bunch of DoF or motion blur, pixel samples of 24 AND sinc is NOT a quality improvement, it's just a time waster.  PS of 4 to 8 is all you need. with 8 being used for ligh to moderate DoF.  Higher is not always better.

Each filter has a 'sweet spot' and none of them are particulary 'high'.