PDA

View Full Version : Mental ray shadows problem


Ryan_M_Mccalla
07-14-2005, 04:55 AM
hi guys, im using mental ray with raytraced lights....
im trying to blur out my shadows, at the moment raytraced lights just cast a really crisp sharp shadow... how can I adjust it so the shadow blurs out the further it is from the object casting them?

-Vormav-
07-14-2005, 05:23 AM
The easiest way is to just use an MR Area light. Play with the radius or height and width, along with the U and V samples settings to get a good balance between detail and render time. Although, even without optimizing the settings, MR's area lights still render out pretty damn fast for area lights, and they automatically have that behavior with raytraced shadows.
You can also fake this effect with shadow shaders on a standard mental ray material. For a quick example, put 'material to shader' as your shadow shader (note: you apply this shader to the object that is casting the shadows, not the objects that are receiving them), and then apply a new standard material to the material slot for the 'material to shader.' On this new standard material, apply a gradient ramp as an opacity map. Set the gradient type to "normal." Or another quick one - instead of the gradient map, use a falloff map, with a falloff type of towards/away, and a falloff direction as your shadow casting object.
Both of the last two examples certainly won't produce results that are as realistic as what you'd get from using raytraced shadows with an MR Area light, but they can get the general idea across, and may be good alternatives if you need to speed up your renders.

Ryan_M_Mccalla
07-14-2005, 05:25 AM
Thanks alot.... its been bugging the heck out of me.. will check it this afternoon.

CGTalk Moderation
07-14-2005, 05:25 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.