xenial (1) pmdblur.1.gz

NAME

       pmdblur - generate views for combined camera motion and depth blurring

SYNOPSIS

       pmdblur speed aperture nsamp v0file v1file

DESCRIPTION

       Pmdblur  takes  two  viewfiles  and generates nsamp views starting from v0file and moving towards v1file,
       simulating an aperture of diameter aperture in  world  coordinate  units.   When  rendered  and  averaged
       together,  these  views  will  result  in  a  picture with motion and depth-of-field blur due to a camera
       changing from v0 to v1 in a relative time unit of 1, whose shutter is open starting at v0  for  speed  of
       these  time units.  Either pinterp(1) or rpict(1) may be called to do the actual work.  (The given v0file
       must also be passed on the command line to the chosen renderer, since pmdblur provides supplemental  view
       specifications only.)

       For  pinterp, feed the output of pmdblur to the standard input of pinterp and apply the -B option to blur
       views together.  In most cases, two pictures with z-buffers at v0 and v1 will get a satisfactory  result,
       though the perfectionist may wish to apply the -ff option together with the -fr option of pinterp.

       To  use  pmdblur  with rpict, apply the -S option to indicate a rendering sequence, and set the -o option
       with a formatted file name to save multiple output pictures.   When  all  the  renderings  are  finished,
       combine  them with the pcomb(1) program, using appropriate scalefactors to achieve an average.  Note that
       using rpict is MUCH more expensive than using pinterp, and it  is  only  recommended  if  the  scene  and
       application absolutely demand it (e.g. there is prominent refraction that must be modeled accurately).

       For  both  pinterp  and  rpict,  the  computation  time  will be proportional to the number of views from
       pmdblur.  We have found a nsamp setting somewhere between 7 and  15  to  be  adequate  for  most  images.
       Relatively larger values are appropriate for faster camera motion.

       The  -pm  and/or -pd options of rpict may be used instead or in combination to blur animated frames, with
       the added advantage of blurring reflections and refractions according to their proper  motion.   However,
       this  option will result in more noise and expense than using pmdblur with pinterp as a post-process.  If
       both blurring methods are used, a smaller value should be given to the rpict  -pm  option  equal  to  the
       shutter  speed  divided by the number of samples, and the -pd option equal to the aperture divided by the
       number of samples.  This will be just enough to blur the boundaries of the ghosts which may appear  using
       pmdblur with a small number of time samples.

       To  simulate  a  particular  camera's aperture, divide the focal length of the lens by the f-number, then
       convert to the corresponding world coordinate units.  For example, if you wish to simulate a 50mm lens at
       f/2.0  in  a  scene  modeled  in meters, then you divide 50mm by 2.0 to get 25mm, which corresponds to an
       effective aperture of 0.025 meters.

EXAMPLES

       To use pinterp to simulate motion blur between two frames of a walk-through animation, where  the  camera
       shutter is open for 1/4 of the interframe distance with an aperture of 0.1 world units:

         pmdblur  .25 .1 8 fr1023.hdr fr1024.hdr | pinterp -B -vf fr1023.hdr -x 640 -y 480 fr1023.hdr fr1023.zbf
         fr1024.hdr fr1024.zbf > fr1023b.hdr

AUTHOR

       Greg Ward

SEE ALSO

       pcomb(1), pdfblur(1), pinterp(1), pmblur(1), rcalc(1), rpict(1), vwright(1)