7 |
|
[ |
8 |
|
.B "\-n nprocs" |
9 |
|
][ |
10 |
+ |
.B \-V |
11 |
+ |
][ |
12 |
|
.B \-fo |
13 |
|
| |
14 |
|
.B \-r |
41 |
|
.B "rtcontrib [ options ] \-defaults" |
42 |
|
.SH DESCRIPTION |
43 |
|
.I Rtcontrib |
44 |
< |
computes ray contributions (i.e., color coefficients) |
44 |
> |
computes ray coefficients |
45 |
|
for objects whose modifiers are named in one or more |
46 |
|
.I \-m |
47 |
|
settings. |
56 |
|
(No search takes place if a file name begins with a '.', '/' or '~' |
57 |
|
character.)\0 |
58 |
|
.PP |
59 |
+ |
By setting the boolean |
60 |
+ |
.I \-V |
61 |
+ |
option, you may instruct |
62 |
+ |
.I rtcontrib |
63 |
+ |
to report the contribution from each material rather than the ray |
64 |
+ |
coefficient. |
65 |
+ |
This is particularly useful for light sources with directional output |
66 |
+ |
distributions, whose value would otherwise be lost in the shuffle. |
67 |
+ |
With the default |
68 |
+ |
.I -V- |
69 |
+ |
setting, the output of rtcontrib is a coefficient that must be multiplied |
70 |
+ |
by the radiance of each material to arrive at a final contribution. |
71 |
+ |
This is more convenient for computing daylight coefficeints, or cases |
72 |
+ |
where the actual radiance is not desired. |
73 |
+ |
Use the |
74 |
+ |
.I -V+ |
75 |
+ |
setting when you wish to simply sum together contributions |
76 |
+ |
(with possible adjustment factors) to obtain a final radiance value. |
77 |
+ |
Combined with the |
78 |
+ |
.I \-i |
79 |
+ |
or |
80 |
+ |
.I \-I |
81 |
+ |
option, irradiance contributions are reported by |
82 |
+ |
.I \-V+ |
83 |
+ |
rather than radiance, and |
84 |
+ |
.I \-V- |
85 |
+ |
coefficients contain an additonal factor of PI. |
86 |
+ |
.PP |
87 |
|
The output of |
88 |
|
.I rtcontrib |
89 |
|
has many potential uses. |
98 |
|
.I Rtcontrib |
99 |
|
calls |
100 |
|
.I rtrace(1) |
101 |
< |
with the -oTW option to calculate the daughter ray |
101 |
> |
with the -oTW (or -oTV) option to calculate the daughter ray |
102 |
|
contributions for each input ray, and the output tallies |
103 |
|
are sent to one or more destinations according to the given |
104 |
|
.I \-o |