Setting Rendering Options

The table below gives some useful ranges for some Radiance 2.4 parameters. The "min" value gives the fastest, crudest rendering. It is not necessarily the smallest value numerically. The "fast" value gives a reasonably fast rendering. The "accur" value gives a reasonably accurate rendering. The "max" value gives the ultimate in accuracy.
Param   Description             Min     Fast    Accur   Max     Notes
=====   ====================    =====   =====   =====   =====   =====
-ps     pixel sampling rate     16      8       4       1
-pt     sampling threshold      1       .15     .05     0
-pj     anti-aliasing jitter    0       .6      .9      1       A
-dj     source jitter           0       0       .7      1       B
-ds     source substructuring   0       .5      .15     .02
-dt     direct thresholding     1       .5      .05     0	C
-dc     direct certainty        0       .25     .5      1
-dr	direct relays		0	1	3	6
-dp	direct pretest density	32	64	512	0	C
-sj	specular jitter		0	.3	.7	1	A
-st	specular threshold	1	.85	.15	0	C
-ab	ambient bounces		0	0	2	8
-aa	ambient accuracy	.5	.2	.15	0	C
-ar	ambient resolution	8	32	128	0	C
-ad	ambient divisions	0	32	512	4096
-as	ambient super-samples	0	32	256	1024
-lr	limit reflection	0	4	8	16
-lw	limit weight		.05	.01	.002	0	C

        A) This option does not affect the rendering time
        B) This option adversely affects image sampling (ie. use -ps 1)
	C) Maximum value disables optimization and can be very expensive



Param Artifact Solution ===== =================================== ========================= -ps "missing pieces" to objects decrease value by 50% -pt some soft edges are very jagged decrease value by 50% -pj diagonal edges are like staircases increase value to 0.9 -pj edges look too erratic decrease value to 0.4 -dj shadows are unnaturally sharp increase value to 0.7 -ds large sources cast unnatural shadows decrease value by 50% -dt some shadows disappear decrease value by 50% -dc inaccurate values with many sources increase value to .75 -dr missing multiple mirror reflections increment value -dp incorrect mirror reflections double value -sj specular reflections too fuzzy decrease value to 0.2 -sj specular reflections too sharp increase value to 1 -st some specular highlights missing decrease value to 0.02 -ab lighting in shadows too flat increment value -av overall light level seems too high/low decrease/increase value -aa uneven shading boundaries in shadows decrease value by 25% -ar shading wrong in some areas double or quadruple value -ad "splotches" of light double value -as "splotches" of light increase to half of -ad setting -lr some multiple specular reflections gone increment value -lw some specular reflections gone decrease value by 50% -------------------------------------------------------------------------


Param Effect on Execution Time ===== ================================================================== -ps inverse, halving value increases rendering time up to four times -pt minor, decreasing value causes modest increase in rendering time -pj no effect -dj indirect, increasing value requires -ps parameter to be reduced -ds inverse, halving value causes rendering time to approximately double -dt inverse, halving value causes rendering time to increase about 50% -dc direct, affects rendering time up to 50% over its 0 to 1 range -dr direct, depending on the scene each new reflection can double time -dp minor, affects start-up time only, higher values take longer -sj no effect -st minor, a value of zero may increase rendering by 50% over maximum of 1 -ab direct, doubling this value can double rendering time -aa direct, doubling this value approximately quadruples rendering time -ar direct, effect depends on scene, can quadruple time for double value -ad direct, doubling value may double rendering time -as direct, effectively adds to -ad parameter and its cost -lr minor, increase causes very slightly longer rendering time -lw minor, decrease causes very slightly longer rendering time