why the light leaks

[salty_dogs]

ok, this is a simple box with architectural units, a couple of window size openings. i've a photometric sun light going with raytrace shadows. whats with the light leaks at the edges? its an acad model. i've tried welding/no welding vertices and other geometery foolishness, flipping normals, etc. arggg!

[DennisHolland]

Set your shadows to 'shadowmap'. At last, you can build a lightblocker (just a box) outside the model and the lightleaks are history....

[sardesign]

looks like your walls are paper thin... i bet they are just regions... am i right? try solids or architectural walls.

[kdavenport]

You could also try making the material on them double-sided; it might be an issue with backface culling. You can do that by clicking on the "Double-Sided" checkbox at the top of the shader rollout in the materal editor.

[salty_dogs]

ok... got rid of the leaks with a little geometry and colinear edges. now how about this reflective floor? the material is a raytrace, with a falloff in the reflector slot. i've got a cloud jpg for a background. a photometric sky and photometric sun. its architectural units.

1. i guess i don't understand how the falloff parameters work, i want the reflections to dissipate as they get further from the window.

2. the sun light is also troublesome. i'd like the edges of the shadow to soften as they move away from the opening.

any ideas?

[pixelperfectg]

1) Try setting the falloff to "fresnel".

2) That's called area shadows. Run a search in the help file for "area shadows" and it will explain them. But in nutshell, you need to use one of the MR area lights or a photometric area light.