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Rendering Parameters Rollout (Radiosit y) 71
and shadows. This second option is usually
slower but more accurate. With Render Direct
Illumination, the radiosity solution provides only
the indirect lighting.
When Render Direct Illumination is the method
you choose, you can turn on regathering to correct
artifacts and shadow leaks. Regathering provides
the slowest but the best-qualit y rendering .
Note: Regatheringisextremelyintensiveforyour
CPU and uses a lot of RAM, so it might not be
practical for print-resolution images (for example,
4000 x 4000 pixels).
Inter face
Re-Use Direct I llumina tion from R adiosi ty
Solution—
3ds Max doesn’t render direct lights,
but uses the direct lighting stored in the radiosit y
solution. If you turn on this option, the Regather
Indirect Illumination option is disabled. The
quality of shadows in the scene depends on the
mesh res olution. Capturing fine shadow det ails
mightrequireafinemesh,butinsomesituations
this option can speed up overall rendering time,
especially for animations, because the lights don’t
have to be recalculated by the scanline renderer.
You should use this option if you are using the
Assign Vertex Colors utility (page 2–1544) .
Left: Direct light only is stored in the radiosity mesh.
Middle: Indirect light on ly is stored in the radiosity me sh.
Right: Direct and ind irect light both stored in the radiosity
mesh(theshadowsareusuallyverycoarse).
Wa rn in g: If you choose this option but haven’t
generated a radiosity solution, rendering generates a
completely black image.
Render Direct Il lumina tion—
3ds Max renders
shadows from the lights at each rendering frame,
and then adds indirect light from the radiosity
solution.Thisisthedefaultrenderingmode.
Left: Direct light calculated only by the scanline rendere r.
Middle: Indirect light calculated only by the radiosity mesh.
Right: Direct and indirect light combined.
Regather Indirect I llumination—In addition to
recalculat ing all the direct lighting, 3ds Max
recalculates the indirect lighting at each pixel by
regather ing illumination data from the existing
radiosity solution. Using this option can produce
themostaccurate,artifact-freeimages,butitcan
add a considerable amount of rendering time.
Note: If you know that you want to use the
regathering option, then typically you don’t need
as dense a mesh for the radiosity solution. Even
if you don’t subdivide the surfaces at all and do
an Initial Quality of 0%, the regathering will
work, and might provide an acceptable visual
result (useful for quick tests as well). However,
accuracy and subtle details depend on the quality
of the radiosit y s olution stored in the mesh.