| 8 |
|
.B "\-n spp" |
| 9 |
|
][ |
| 10 |
|
.B "\-h|\-q" |
| 11 |
+ |
][ |
| 12 |
+ |
.B "\-l maxlobes" |
| 13 |
|
] |
| 14 |
|
[ |
| 15 |
|
.B "bsdf.sir .." |
| 37 |
|
][ |
| 38 |
|
.B "{+|-}backward" |
| 39 |
|
][ |
| 40 |
< |
.B "\-e expr |
| 40 |
> |
.B "\-e expr" |
| 41 |
|
][ |
| 42 |
< |
.B "\-f file |
| 42 |
> |
.B "\-f file" |
| 43 |
|
] |
| 44 |
|
.B bsdf_func |
| 45 |
|
.SH DESCRIPTION |
| 62 |
|
option may be used to reduce this number to 41 patches. |
| 63 |
|
Neither option is recommended unless the distribution is known to |
| 64 |
|
be approximately diffuse. |
| 65 |
+ |
The |
| 66 |
+ |
.I \-l |
| 67 |
+ |
option may be used to specify the maximum number of lobes in any |
| 68 |
+ |
interpolated radial basis function. |
| 69 |
+ |
The default value is 15000, which generally keeps the interpolation tractable. |
| 70 |
+ |
Setting the value to 0 turns off this limit. |
| 71 |
|
.PP |
| 72 |
|
Normally, multiple samples are taken from random points on each input |
| 73 |
|
and output patch to improve accuracy. |
| 98 |
|
In the third invocation form, |
| 99 |
|
.I bsdf2klems |
| 100 |
|
takes a functional specification of a BSDF. |
| 101 |
< |
The named function must accept 6 parameters corresponding to the |
| 101 |
> |
The named function should accept 6 parameters corresponding to the |
| 102 |
|
normalized incident and exiting vectors, respectively. |
| 103 |
|
By convention, these vectors point away from the surface, and a positive |
| 104 |
|
Z-component corresponds to the front side. |
| 105 |
|
The Y-component corresponds to the "up" orientation of the surface, |
| 106 |
|
as specified in the eventual scene description that references the XML |
| 107 |
|
output. |
| 108 |
+ |
If the function only takes 3 parameters, then the variables "Dx", "Dy", |
| 109 |
+ |
and "Dz" will be assigned to the reverse of the outgoing direction at |
| 110 |
+ |
each evaluation. |
| 111 |
+ |
(I.e., the vector will point into the surface and |
| 112 |
+ |
Dz will be negative on the front side.)\0 |
| 113 |
+ |
This simplifies conversion of functional BSDF specifications using the |
| 114 |
+ |
legacy material primitives "plasfunc", "metfunc", and "transfunc". |
| 115 |
|
.PP |
| 116 |
|
The function is defined by one or more |
| 117 |
|
.I \-e |
