[Sidefx-houdini-list] rectangular pbr area light

paul simpson paul at realisestudio.com
Tue Dec 11 06:14:03 EST 2007


....or, just scale the light in x.

On 07/12/2007, Erika Salatiello <tictacer at hotmail.com> wrote:
>
>
> what was the highest you tried for a pixel sampling rate? it's possible
> you may have to go higher - i've had to use values above 60 before.  By
> default, in less you really go crazy with it, I think you're always going to
> have a  bit more noise with pbr> Date: Fri, 7 Dec 2007 18:03:44 +0100> From:
> lulu at alamaison.fr> To: sidefx-houdini-list at sidefx.com> Subject: Re:
> [Sidefx-houdini-list] rectangular pbr area light> > Mario Marengo a écrit :>
> > On December 7, 2007 09:13 am, Luc Froehlicher wrote:> > > >> is it
> possible to have rectangular area light (H9 PBR) ?> >> luc> >> > >> > If
> what you want is a *square* area light (not rectangular), then you can use >
> > an area light set to "Grid". You can choose among several basic
> symmetrical > > shapes with this approach, and it works in every rendering
> engine.> > > well I need to mimic kino flo's type of light.> I noticed that
> if I edit the interface there's a parameter vm_areasize > in Mantra/Light>
> (2 floats array) but it doesn't seem to have any influence.> > If you want
> an actual rectangle, or some other arbitrary shape, then create > > the
> emitter geometry and assign it a constant shader (vex_constant will do), > >
> then make sure your ROP's "Diffuse Limit" is set to 1 or higher, else you >
> > won't get a diffuse contribution (Glossy Limit defaults to 1 I believe, so
> > > you'll get one bounce of specular, but no diffuse, by default).> >
> Anyway, I guess the main point is: assigning a constant value (as opposed to
> > > bsdf) to the global F in a shader is equivalent to defining an emitter
> with > > the given value as its power.> > Also, you'll likely need to raise
> "Pixel Samples" in the ROP to something > > higher than default to reduce
> sampling noise.> > > I tried that and increased the diffuse value but , as
> you say , it's > very noisy :(> thanks for helping.> luc> >> > > > >
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