JSR wrote:

> Hi,
> I'm trying to improve aliasing in my small images. The problem is that when
> I render at small resolutions (< 800x600) the result always has aliasing in
> the thin lines, but when I render at high (> 3000x1500) the problem is
> solved.
> 
> I've tried with:
> Option 1: +a0.1
> Option 2: +am2 +r8 +a0.01
> And the problem persist in both images (as you can see in attached file).

It's simple.  At the lower resolution, one pixel will be to one side of 
the thin line of grout, and the other pixel will be to the other side of 
the thin line of grout.  Both pixels hit the tile instead, and because 
they come out with very close rgb values, the renderer sees no reason to 
anti-alias further.

At the higher resolution levels, the thin line gets hit at least once by 
a pixel, and the aa settings see it through to the right result after that.

Your solutions are:

1.  Set the aa threshold to zero, and the sampling method and depth so 
that every primitive gets hit when it is part of any pixel.  This will 
make things take longer.

2.  Render at a much higher resolution with no aa at all, and then use 
some kind of post-processing to combine each block of pixels into a 
final pixel.

3.  Patch POV-Ray so that you can specify a higher level of aa for 
certain regions, and lower settings for others.

Regards,
John

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