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.SH SYNOPSIS |
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.B bsdf2ttree |
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[ |
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.B "\-pC" |
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][ |
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.B "\-g Nlog2" |
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][ |
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< |
.B "\-t pctcull |
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.B "\-t pctcull" |
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> |
][ |
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> |
.B "\-l maxlobes" |
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] |
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[ |
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.B "bsdf.sir .." |
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.B bsdf2ttree |
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.B "\-t{3|4}" |
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[ |
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+ |
.B "\-pC" |
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+ |
][ |
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.B "\-g Nlog2" |
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][ |
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< |
.B "\-t pctcull |
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> |
.B "\-t pctcull" |
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][ |
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.B "{+|-}forward" |
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][ |
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.B "{+|-}backward" |
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][ |
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< |
.B "\-e expr |
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> |
.B "\-e expr" |
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][ |
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< |
.B "\-f file |
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> |
.B "\-f file" |
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] |
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.B bsdf_func |
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.SH DESCRIPTION |
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A complete XML description is written to the standard output, |
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which is normally redirected to a file. |
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.PP |
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The |
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.I \-p |
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option by itself turns off the progress bar, whose length may be set |
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by an immediately following integer argument. |
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(The default progress bar length is 79 characters.)\0 |
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.PP |
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The maximum resolution of the tensor tree may be controlled by the |
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.I \-g |
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option, which defaults to a value of 6. |
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the four components, and if the first component |
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is isotropic, all components must be isotropic. |
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A similar rule holds for anisotropic inputs. |
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The |
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.I \-l |
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option may be used to specify the maximum number of lobes in any |
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interpolated radial basis function. |
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The default value is 15000, which generally keeps the interpolation tractable. |
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Setting the value to 0 turns off this limit. |
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.PP |
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In the second invocation form, |
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.I bsdf2ttree |
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takes a functional specification of a BSDF. |
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< |
The named function must accept 6 parameters corresponding to the |
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> |
The named function should accept 6 parameters corresponding to the |
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normalized incident and exiting vectors, respectively. |
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By convention, these vectors point away from the surface, and a positive |
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Z-component corresponds to the front side. |
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The Y-component corresponds to the "up" orientation of the surface, |
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as specified in the eventual scene description that references the XML |
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output. |
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If the function only takes 3 parameters, then the variables "Dx", "Dy", |
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and "Dz" will be assigned to the reverse of the outgoing direction at |
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each evaluation. |
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(I.e., the vector will point into the surface and |
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Dz will be negative on the front side.)\0 |
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This simplifies conversion of functional BSDF specifications using the |
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legacy material primitives "plasfunc", "metfunc", and "transfunc". |
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.PP |
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The function is defined by one or more |
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.I \-e |
