srahul nous apporta ses lumieres en ce 2007/06/22 09:11:
> I need to render the image acquired by focussing a camera (perspective) at a
> curved mirror (spherical and other shapes).
> 
> the question is:
> 
> 1/ How do I set up the exact objective focal distance (not focal length) of
> the camera to focus at a specific plane depth.
> 2/ How do I specify the depth of field so as to control how much of the
> scene is in focus.
> 
> quick help will be highly appreciated.
> 
> Rahul
> -
> 
> 
The default camera is a pinhole camera with infinite focal depth.
You can simulate a "real" camera by using the focal blur options. For that you 
need to add the folowing keywords to control it:
aperture, determine the depth. Large = small area in focus, small = large area 
in focus.
focal_point is a vector that set the plane of maximum sharpness, that plane is 
perpendiculat to the axis of the camera.
blur_samples set the maximum number of samples taken, a quality parameter.
confidance and variance control the adaptive sampling and affect the quality.
Please read the documentation in the camera section, focal blur subsection: 
3.3.1.3 in the windows version.

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 >Can you suggest a way for me to then achieve this kind of synthetic imagery?
 >If not using PovRay, is there another option?
Maybe, it depends on what application you use.

 >Also, can the depth of field be "simulated" for  given object distance
 >focus?
What do you mean by that?
If you use focal blur and the scene include lences or curved mirrors, the shape 
of those object, and ior for transparent ones, will affect the area of sharpness 
for the parts of the scene seen trough, or reflected by, those objects.
If you mean having the focal point "on" an object, you can use the trace 
function to find the position of a point on the surface of the object and use 
that as the focal_point value. The focal_point DON'T need to reside on the 
camera axis. A camera like this one:
camera{location -10*z /*or <0,0,-10>*/ look_at 0 aperture 0.1 focal_point 
<1,9,3>} is legal and the focal plane will be at +3*z or <0,0,3>.

-- 
Alain
-------------------------------------------------
I'm interested in the fact that the less secure a man is, the more likely he is 
to have extreme prejudice. (Clint Eastwood)

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