Stefan Viljoen <rylan@ <deletehis> wrote:
> 2. How exactly to use adc_bailout?

  If I'm not completely mistaken, adc_bailout does not work in POV-Ray 3.5
due to a bug, but AFAIK this has been fixed in POV-Ray 3.6.

> 4. Pointers / hints?

http://tag.povray.org/povQandT/miscQandT.html#renderingspeed

> 5. Reasons for scanline renderers being faster - is scanline better?

  Basically scanline rendering makes tons of shortcuts to produce images
which look similar to raytraced images, but which really aren't. There
are many things which are practically impossible to do with a scanline
renderer and which are trivial with a raytracer (for example two
reflecting objects reflecting each other again and again and again).

  If a raytracer used the same tricks as most scanline renderers to
achieve certain effects (such as shadows by using lightmaps instead of
tracing, reflections using reflection maps instead of tracing, using
only triangles to build the scene, etc etc) it would speed it up
considerably. However, raytracers are usually not intended for that:
When you want a raytracer you want it because you want precise shadows,
precise reflections, precise refractions, precise mathematical surfaces etc.

  Another reason is that most effects are very easy to implement with
a raytracer but very laborious to implement in a scanline renderer.
For example the reflection calculations in a raytracer (once you have
the basic tracing function done) can perfectly be done in less than 10
lines of simple code. In a scanline renderer good-looking reflections
require thousands of lines of complicated code (in addition to the
basic triangle projection code).

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -

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