[Sidefx-houdini-list] rectangular pbr area light

Pablo Giménez pablogipi at gmail.com
Tue Dec 11 15:30:30 EST 2007


2007/12/11, Robert Magee <rmagee at sidefx.com>:
>
> You can also parent the light to a null object and scale the null object
> non-proportionally.
>
> The reason that Scale is not on lights by default is that scaling lights
> can cause big problems for shadow generation when using depth map
> shadows (the same for cameras). People often scale lights and cameras to
> make them more visible in the scene and then the renderings don't work
> correctly. The scale icon parameter therefore lets you change the icon
> without affecting the shadowing.
>
> If you choose to scale your lights (using null object or edit parameter)
> it should therefore only be used with raytracing and PBR style
> renderings. The null object will do the trick and should be used only
> when you are not using depth map shadows.


Yes I remember getting crazy renders due to a camera scaling.
So here is the question is there any way to scale cameras and lights without
having problems with micropoligon rendering?
I know is not usual to scale these kind of things but only in case ....

We will put an RFE in to offer a rectangle shape in the area light and
> offer two parameters for its size.
>
> Robert
>
> Luc Froehlicher wrote:
> > Fred here show me the trick to do it:
> > Edit Parameter - > create a new vector parameter called Scale (l_s)
> > and in the Channels Tab -> Linked Channels type ./sx ./sy ./sz . it
> works
> >
> > another question about environment light :
> > I noticed that NoAttenuation and HalfDistanceAttenuation  gives
> > different illumination.(this is without PBR)
> > Physically correct is always black.
> > is this correct ?
> >
> > Pablo Giménez a écrit :
> >
> >> 2007/12/11, paul simpson <paul at realisestudio.com>:
> >>
> >>
> >>> you welcome.  from what i remember mark telling me - you have to
> create a
> >>> new light asset with scaling enabled.  however, it's bit of a hoop to
> jump
> >>> through for such a common need.  i think that new users would find
> this
> >>> unnecessarily complex.  maybe this is a good reason to have scaling
> >>> allowable as default (MarkE)?
> >>>
> >>> i may be missing something obvious here.  i'd be keen to hear from
> sesi
> >>> about "best pratice" on this issue - specifically dealing with area
> >>> lights.
> >>> i'm hoping that we'll have a nice suite of lighting tools and shaders
> for
> >>> 9.1.  ie, uberlights, magic lights, and some bullet proof uber shaders
> >>> (made
> >>> out of lots of v useful mini shader assets).
> >>>
> >>> the quicker the power of mantra is opened up to the masses - the
> sooner
> >>> houdini will receive the attention (and sales) that it deserves...
> >>>
> >>>
> >> Complitely agree
> >>
> >> On 11/12/2007, Luc Froehlicher <lulu at alamaison.fr> wrote:
> >>
> >>
> >>>> effectively if i parent the light under a null and scale the null it
> >>>> works as expected
> >>>> how do you add a scaling properties directly on the light ?
> >>>> thanks paul.
> >>>>
> >>>> Mario Marengo a écrit :
> >>>>
> >>>>
> >>>>> On December 11, 2007 06:14 am, paul simpson wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>> ....or, just scale the light in x.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> Heh... goes to show how much I use area lights... didn't even think
> to
> >>>>>
> >>>>>
> >>>> try
> >>>>
> >>>>
> >>>>> that! :)
> >>>>>
> >>>>> Thanks Paul.
> >>>>>
> >>>>> P.S: hmmm... the H9 lights don't have scaling properties available
> by
> >>>>> default... I wonder why?... anyhoo... back to work
> >>>>>
> >>>>>
> >>>>>
> >>>>>
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> >>>>
> >>>>
> >>>>
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> >>>
> >>>
> >>
> >>
> >>
> >
> >
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> >
>
>
> --
> Robert Magee
> Product Marketing Manager
> Side Effects Software Inc.
> www.sidefx.com
> 416 504-9876 x327
>
>
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-- 

Un saludo
Best Regards
Pablo Giménez



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