CGTalk - Area shadows and GI

Bob3D

01-09-2006, 09:46 PM

This is really hacking me off now, because I'm sure I've done it before, but now I just can't remember or find out how - I'm sure it's so simple.

I have a city scene lit with radiosity, using just a plane-coloured sky object. Of course, this doesn't produce any proper shadows, so I want a light that will cast them, but without lighting the scene.

So how do make a light do nothing more than produce a shadow using area shadows?

Thanks,

Bob

tcastudios

01-09-2006, 09:53 PM

Make two identical lights. Engage shadow on one and set the other to the equal -negative- brightness value as the one with shadow. In 9.5 it's included as a option of a lightobject.
And I think there was a plugin doing this as well.

Cheers
Lennart

Per-Anders

01-09-2006, 10:01 PM

um, on your light details->shadow caster

nutriman

01-10-2006, 10:41 AM

um, on your light details->shadow caster

that works from 9.5 up.. ;)

STRAT

01-10-2006, 11:07 AM

for earlier versions of cine you need to do as tcastudios says. just create 2 lights in the same place -

1 with a positive brightness setting emmiting your shadow, the other with a minus brightness setting of the same opposite amount not emmiting a shadow. the lights will cancel each other out, but the shadow remains.

tcastudios

01-10-2006, 11:36 AM

The plugin I was refering to is now included in LUMEN by 3DATTACK.net . It includes a Shadow only LightObject. I don't know if that is included in the free version of LUMEN or not.
Just see yourself.

Cheers
Lennart

Bob3D

01-10-2006, 07:31 PM

Aye, I'm stuck with 9.1 XL atm. The negative/positive trick works a treat :)

Thanks, guys.

Bob

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