2. Global Parameters - These affect everything

Global parameters specified in the scene file affect the whole render. A sample scene file listing of the global parameters is given below. The
paramemters can occur anywhere in the scene file and in any order, though specifying them on the top together is a good idea.
A sample scene file listing -

resolution 1
max_depth 4
min_weight 0.001
antialias_samples 9
shadow_feelers 3
ambient_color 1.0 1.0 1.0
ambient_coeff 0.2

1. Image Resolution (a `Progressive Trace' ??) -
   The resolution parameter allows the user to get a quick preview of his render at a lower resolution. A resolution of 2 means that 1 ray is shot for a evert
   block of 2x2 pixels. Whenever resolution is more than 1, anti-aliasing is automatically turned of even if the anti-aliasing samples parameter is specified.
   The default resolution is 1.
   
   

   Resolution : 8	Resolution : 4	Resolution : 1

   
   
2. Maximum Depth of Recursion (a bound on adaptive depth control ) -
   The maximum depth is a absolute higher bound on the depth of recursion. The recursion depth is otherwise controlled adaptively using the minimum weight
   parameter. This parameter is not optional so it has to be specified by the user.
   
   

   Maximum depth : 1	Maximum depth : 2	Maximum depth : 5

   
   
3. Minimum Weight -
   The minimum weight parameter is responsible for the adaptive depth control of recursion. When the accumulated light intensity (due to secondary rays)
   at any level of recursion falls below this weight, the recursion stops. The default value of minimum weight is 0.001.
   
   
4. Number of Anti-aliasing samples -
   These are the number of samples used to anti-alias the generated image. The default value is 1, which means that no anti-aliasing is being done. This
   parameter ceases to have any effect if the resolution parameter is more than 1. More information about anti-aliasing is available here.
   
   
5. Number of Shadow Feelers -
   This parameter governs how many shadow rays are shot out from a point for producing soft-shadows when using area-light sources.The default value
   is 1, which means that no soft-shadows are produced. More information about soft-shadows is available here.
   
   
6. Ambient Illumination Parameters -
   These are two parameters which control ambient illumination in the scene. One is the color of ambient light to be specified as a RGB triad. The color
   values can range from 0.0 - 1.0 for each component. The other parameter is the coefficient of ambient illumination which governs its strength.
   This can also range from 0.0 - 1.0. These parameters are not optional so they have to be specified by the user.

Page last updated on 04 October, 2005.	AT cse.iitd.ac.in	© Parag Chaudhuri , 2009