PMAPDUMP(1)

NAME
pmapdump - generate RADIANCE scene description of photon map distribution

SYNOPSIS
pmapdump [-n nspheres1] [-r radscale1] pmap1 [-n nspheres2] [-r radscale2] pmap2 ...

DESCRIPTION
pmapdump takes one or more photon map files generated with mkpmap(1) as input and sends a RADIANCE scene description of their photon distributions to the standard output. This can be visualised with e.g. objview(1), rpict(1), or rvu(1) to assess the location and local density of photons in relation to the scene geometry.

An arbitrary number of photon maps can be specified on the command line and the respective photon type is determined automagically. The different photon types are visualised as colour coded spheres according to the following schema:

    Blue: global photons
    Cyan: precomputed global photons
    Red: caustic photons
    Green: volume photons
    Magenta: direct photons
    Yellow: contribution photons

OPTIONS
Options are effective for the photon map file immediately following on the command line, and are reset to their defaults after completion of each dump. As such they may be set individually for each photon map.

-n nspheres
    Specifies the number of spheres to dump for the next photon map. The dump is performed by random sampling with nspheres as target count, hence the number actually output will be approximate. Nspheres may be followed by a multiplier suffix for convenience, where k = 10^3 and m = 10^6, although the latter may lead to problems when processing the output geometry with oconv(1). The default number of spheres is 10k.

-r radscale
    Specifies a relative scale factor radscale for the sphere radius. The sphere radius is determined automatically from an estimated average distance between spheres so as to reduce clustering, assuming a uniform distribution. In cases where the distribution is substantially nonuniform (e.g. highly localised caustics) the radius can be manually corrected with this option. The default value is 1.0.

NOTES
The output may contain many overlapping spheres in areas with high photon density, particularly in caustics. This results in inefficient and slow octree generation with oconv(1). Generally this can be improved by reducing nspheres and/or radscale.

EXAMPLES
To visualise the distribution of global and caustic photons superimposed on the scene geometry with 5000 and 10000 spheres, respectively:

    pmapdump -n 5k global.pm -n 10k caustic.pm | oconv - scene.rad > scene_pmdump.oct

Alternatively, the dump may be viewed on its own by piping the output of pmapdump directly into objview(1) (using the default number of spheres in this example):

    pmapdump zombo.pm | objview

AUTHOR
Roland Schregle (roland.schregle@{hslu.ch,gmail.com})

COPYRIGHT
(c) Fraunhofer Institute for Solar Energy Systems, Lucerne University of Applied Sciences and Arts.

ACKNOWLEDGEMENT
Development of the RADIANCE photon mapping extension was sponsored by the German Research Foundation (DFG) and the Swiss National Science Foundation (SNF).

SEE ALSO
mkpmap(1), objview(1), oconv(1), rpict(1), rvu(1), The RADIANCE Photon Map Manual