CAD tip # 898:

  
 
(c:rpref "ropt" STYPE ALIAS RSRVD TSAMP MINB MAXB
  TOSSBACK BACKNORM RAYDEPTH)  
 
STYPE= "ascan" or "aray"  
ALIAS= 1 NHNV  
2 AHNV  
3 AHSV (2x2)  
4 AHSV3 (3x3)  
5 AHSV4 (4x4)  
RSRVD= 0 !MUST be zero  
TSAMP= 1 Point  
2 Linear  
3 Mip map  
MINB= real !Shadow map min bias  
MAXB= real !Shadow map max bias  
TOSSBACK= 0 FALSE !Off  
1 TRUE !On  
BACKNORM= 0 FALSE !Off  
1 TRUE !On  
RAYDEPTH= int !Number of bounces a ray can take  
 
BUGS:  
You must turn off the Render Information Dialog while using this API.  
 
Bringing up the Rendering Information or  
Rendering Preferences dialogresets these values  
to their database values if a rPlus renderer is  
the current renderer.  
 
Calling the API will set all values except  
RAYDEPTH which is set only if STYPE == "ARAY".  
 
EXAMPLES:  
 
(c:rpref "TOGGLE" "SKIPRDLG" "OFF") !Turn off Rend Info Dlg  
(c:rpref "ROPT" "ARAY" 2 0 2 2.0 4.0 0 1 3) !Defaults, raydepth set  
(c:rpref "ROPT" "ASCAN" 2 0 2 2.0 4.0 0 1 3) !Defaults, raydepth not set  
(c:rpref "ROPT" "ASCAN" 2 NIL 2 NIL NIL 0 1 3) !Shows values skipped  
(c:rpref "ROPT" "ARAY" 2 NIL 2) !Shows values skipped & quick end