| 7 |
|
[ |
| 8 |
|
.B "\-n nprocs" |
| 9 |
|
][ |
| 10 |
+ |
.B \-V |
| 11 |
+ |
][ |
| 12 |
+ |
.B \-fo |
| 13 |
+ |
| |
| 14 |
|
.B \-r |
| 15 |
|
][ |
| 16 |
|
.B "\-e expr" |
| 20 |
|
.B "\-o ospec" |
| 21 |
|
][ |
| 22 |
|
.B "\-b binv" |
| 23 |
+ |
][ |
| 24 |
+ |
.B "\-bn nbins" |
| 25 |
|
] |
| 26 |
|
{ |
| 27 |
|
.B "\-m mod | \-M file" |
| 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 |
| 106 |
|
If a destination begins with an exclamation mark ('!'), then |
| 107 |
|
a pipe is opened to a command and data is sent to its standard input. |
| 108 |
|
Otherwise, the destination is treated as a file. |
| 109 |
< |
An existing file of the same name is clobbered, unless the |
| 109 |
> |
An existing file of the same name will not be clobbered, unless the |
| 110 |
> |
.I \-fo |
| 111 |
> |
option is given. |
| 112 |
> |
If instead the |
| 113 |
|
.I \-r |
| 114 |
< |
option is specified, in which case data recovery is attempted. |
| 114 |
> |
option is specified, data recovery is attempted on existing files. |
| 115 |
|
If an output specification contains a "%s" format, this will be |
| 116 |
|
replaced by the modifier name. |
| 117 |
|
The |
| 122 |
|
specification if present. |
| 123 |
|
The actual bin number is computed at run time based on ray direction |
| 124 |
|
and surface intersection, as described below. |
| 125 |
+ |
If the number of bins is known in advance, it should be specified with the |
| 126 |
+ |
.I \-bn |
| 127 |
+ |
option, and this is critical for output files containing multiple values |
| 128 |
+ |
per record. |
| 129 |
+ |
Since bin numbers start from 0, the bin count is always equal to |
| 130 |
+ |
the last bin plus 1. |
| 131 |
+ |
Set the this value to 0 if the bin count is unknown (the default). |
| 132 |
|
The most recent |
| 133 |
< |
.I \-b |
| 133 |
> |
.I \-b, |
| 134 |
> |
.I \-bn |
| 135 |
|
and |
| 136 |
|
.I \-o |
| 137 |
|
options to the left of each |
