PMBLUR(1)                                                            PMBLUR(1)



NNAAMMEE
       pmblur - generate views for camera motion blurring

SSYYNNOOPPSSIISS
       ppmmbblluurr ssppeeeedd nnssaammpp vv00ffiillee vv11ffiillee

DDEESSCCRRIIPPTTIIOONN
       _P_m_b_l_u_r  takes  two  viewfiles  and  generates _n_s_a_m_p views starting from
       _v_0_f_i_l_e and moving towards _v_1_f_i_l_e_.  When rendered and averaged together,
       these  views  will result in a picture with motion 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 _s_p_e_e_d of these time units.  Either _p_i_n_t_e_r_p_(_1_)
       or _r_p_i_c_t_(_1_) may be called to do the actual  work.   (The  given  _v_0_f_i_l_e
       must  also  be passed on the command line to the chosen renderer, since
       _p_m_b_l_u_r provides supplemental view specifications only.)

       For _p_i_n_t_e_r_p_, feed the output of _p_m_b_l_u_r to the standard input of _p_i_n_t_e_r_p
       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 _-_f_f option together with
       the _-_f_r option of _p_i_n_t_e_r_p_.

       To use _p_m_b_l_u_r with _r_p_i_c_t_, apply the _-_S option to indicate  a  rendering
       sequence, and set the _-_o option with a formatted file name to save mul-
       tiple output pictures.  When all the renderings are  finished,  combine
       them  with  the  _p_c_o_m_b_(_1_)  program,  using  appropriate scalefactors to
       achieve an average.  Note that using _r_p_i_c_t is MUCH more expensive  than
       using  _p_i_n_t_e_r_p_, 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  _p_i_n_t_e_r_p and _r_p_i_c_t_, the computation time will be proportional
       to the number of views from _p_m_b_l_u_r_.  We  have  found  a  _n_s_a_m_p  setting
       somewhere  between 5 and 10 to be adequate for most images.  Relatively
       larger values are appropriate for faster camera motion.

       The _-_p_m option of _r_p_i_c_t 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 _p_m_b_l_u_r with _p_i_n_t_e_r_p as
       a post-process.  If both blurring methods are  used,  a  smaller  value
       should  be  given  to  the  _r_p_i_c_t _-_p_m option equal to the shutter speed
       divided by the number of pmblur views.  This will  be  just  enough  to
       blur  the boundaries of the ghosts which may appear using _p_m_b_l_u_r with a
       small number of time samples.

EEXXAAMMPPLLEESS
       To use _p_i_n_t_e_r_p 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:

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

AAUUTTHHOORR
       Greg Ward

BBUUGGSS
       Changes in the view shift and lift vectors or the fore and aft clipping
       planes are not blurred.

SSEEEE AALLSSOO
       pcomb(1),  pdfblur(1),  pinterp(1),  pmdblur(1),  rcalc(1),   rpict(1),
       vwright(1)



RADIANCE                            3/3/98                           PMBLUR(1)
