shadow mapping problem

shadow mapping problem

Post by semzo » Sat, 29 May 1999 04:00:00



basic info : Im running 3dsmax 2.5 in win98 on a PIII 450 128MB

    since the release of the new starwars movie, i wanted to do my own
animation of starwars space ships and stuff so i downloaded the *.3DS files
of the nebulon frigate and xwing from the starwars 3d modelling allince.
After importing the mesh to max, i had to reapply all maps, but they were
automatically in the corect spots on the mesh...now, when i render it
without shadows it looks perfect (i havent added any uvw mapping coordinates
to either mesh) now when i use a direct light on them with shadow mapping,
the shadows dont appear or some faces of the mesh disappear .  if fooled
around with the shadow map size parameters and sometimes it will appear, but
not correctly (do i need uvw coordinates?) .  The problem is if i add uvw
coordinates, the maps will be in all the wrong places because it will change
the original coords.   The shadows and maps are enabled in the render dialog
and under the direct light's modifier (shadow maps enabled) .  i should
mention raytraced shadows are perfect , but i dont want to wait that
long...i know i have plenty of ram for the scene because the indicator in
the render progress window show only 110MB being used. Any ideas on how to
add uvw without disturbing the perfect placement of the materials/maps or
suggestion for fixing  missing faces or bad shadow mapping?
PLEASE reply .

                                        -Derek

 
 
 

shadow mapping problem

Post by jobber » Sun, 30 May 1999 04:00:00


You should raise the map size, default is 256, depending on the scale of the
scene you should use a higher value. I ususally set the value to 1024 by
default, but sometimes I use 2048 for good crispyness. You say Raytraced
shadows look OK, so try to raise the map size as far as is needed to getr
the same crispy effect. By the way there are also tricks to speed up
raytracing: Raising the value of the quadtree depth (in the render dialog)
sometimes speeds it up by 100% (10 instead of 7) and also try to exclude all
unnescesary objects (or toggle the "cast shadows" attribute off in the
object properties).
jobbert

 
 
 

shadow mapping problem

Post by semzo » Sun, 30 May 1999 04:00:00


Thanks!! i upped the shadow map size to 4096 and its great!!


>You should raise the map size, default is 256, depending on the scale of
the
>scene you should use a higher value. I ususally set the value to 1024 by
>default, but sometimes I use 2048 for good crispyness. You say Raytraced
>shadows look OK, so try to raise the map size as far as is needed to getr
>the same crispy effect. By the way there are also tricks to speed up
>raytracing: Raising the value of the quadtree depth (in the render dialog)
>sometimes speeds it up by 100% (10 instead of 7) and also try to exclude
all
>unnescesary objects (or toggle the "cast shadows" attribute off in the
>object properties).
>jobbert

 
 
 

1. Shadow Maps Problem



There's a bug with BMRT shadow map lookups.  I've fixed it a few
weeks back on the Linux glibc2 and the Windoze versions.  You
must be using some other platform, right?  I've not yet gotten
the chance to recompile all the other platforms and get updates
out.  

      -- lg

--
Larry Gritz                                     Exluna

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