Without anti-aliasing
POV-Ray has several anti-aliasing techniques: (see POV-Ray tutorial for more details)
When anti-aliasing is turned on, POV-Ray attempts to reduce the errors by shooting more than one viewing ray
into each pixel and averaging the results to determine the pixel's apparent color. This technique is called super-sampling
and can improve the appearance of the final image but it drastically increases the time required to render a
scene since many more calculations have to be done.
Type 1 is adaptive because not every pixel is super-sampled. POV-Ray initially traces one ray per pixel.
If the color of a pixel differs from its neighbors (to the left or above) by more than a threshold value then the
pixel is super-sampled by shooting a given, fixed number of additional rays. The default threshold is 0.3.
Type 2 is recursive because the pixel is sub-divided and sub-sub-divided recursively. It starts by tracing
four rays at the corners of each pixel. If the resulting colors differ more than the threshold amount additional
samples will be taken. This is done recursively, i.e. the pixel is divided into four sub-pixels that are separately
traced and tested for further subdivision. The advantage of this method is the reduced number of rays that have
to be traced. Samples that are common among adjacent pixels and sub-pixels are stored and reused to avoid re-tracing
of rays. The recursive character of this method makes the super-sampling concentrate on those parts of the pixel
that are more likely to need super-sampling (see figure below). The depth determines the maximum number
of subdivisions allowed.
Another way to reduce aliasing artifacts is to introduce noise into the sampling process. This is called jittering and works because the human visual system is much more forgiving to noise than it is to regular patterns. The location of the super-samples is jittered or wiggled a tiny amount when anti-aliasing is used. Jittering is used by default
Antialias=bool |
Turns anti-aliasing on/off |
+A |
Turns aa on with threshold 0.3 or previous amount |
-A |
Turns anti-aliasing off |
Sampling_Method=n |
Sets aa-sampling method (1 or 2) |
+AMn |
Same as Sampling_Method=n |
Antialias_Threshold=n.n |
Sets anti-aliasing threshold |
+An.n |
Sets aa on with aa-threshold at n.n |
-An.n |
Sets aa off (aa-threshold n.n in future) |
Jitter=bool |
Sets aa-jitter on/off |
+J |
Sets aa-jitter on with 1.0 or previous amount |
-J |
Sets aa-jitter off |
Jitter_Amount=n.n |
Sets aa-jitter amount to n.n. If n.n <= 0 aa-jitter is set off |
+Jn.n |
Sets aa-jitter on; jitter amount to n.n. If n.n <= 0 aa-jitter is set off |
-Jn.n |
Sets aa-jitter off (jitter amount n.n in future) |
Antialias_Depth=n |
Sets aa-depth (1 <= n <= 9) |
+Rn |
Same as Antialias_Depth=n |