[Sidefx-houdini-list] instance light + light mask

Larry Giunta larry at gcreativestudios.com
Thu Jul 7 19:04:07 EDT 2011


Thanks for the feedback Skk,

I'll need to wrap my mind around that a bit. Gotta love the warning  
in the description on that node under help.

Man, I thought there would have been a more straight forward way to  
control light masks for instanced lights.

Larry

On Jul 7, 2011, at 6:30 PM, Szymon Kapeniak wrote:

> Hey Larry, the trick mentioned by Peter seems to work, but not in  
> light masks on objects. Try masks in illuminance loop instead.  If  
> I recall correctly this is because an instance name is treated in  
> Houdini as an error (since such light doesn't exist yet), and never  
> get passed to IFD file. Shaders parms are sent as such, so they can  
> work with light's names valid only for Mantra.
>
> skk.
>
> Dnia 7 lip 2011 o godz. 23:27 Larry Giunta  
> <larry at gcreativestudios.com> napisał(a):
>
>> Thanks Peter. I guess this is not as easy as I had hoped.
>>
>> ok, I do find this syntax for the light name in the IFD.
>> ray_property object name "/obj/light1:/obj/instance1:0"
>>
>> However, I'm trying all kinds of variations of that name in the  
>> light mask and still no luck.
>> Looks like it might be time to hit up support for thoughts on this  
>> unless the above info provides any clues to you.
>>
>> Thanks again for your help and feedback.
>>
>> Larry
>>
>> On Jul 7, 2011, at 3:49 PM, Peter Bowmar wrote:
>>
>>> Hi Larry,
>>>
>>> As I recall, this is tricky but possible. The issue is that the
>>> instanced lights get renamed by the instancer. I think you have to
>>> look inside the IFD file to get the "actual" name of the instanced
>>> light... If the light is "MyLight" in the Houdini file, it might
>>> become "MyLight-1" or something but I forget exactly. Sorry I can't
>>> help more...
>>>
>>> Cheers,
>>>
>>> Peter B
>>>
>>> On 7 July 2011 09:55, Larry Giunta <larry at gcreativestudios.com>  
>>> wrote:
>>>> hello all. I hope this is a simple question.
>>>>
>>>> I'm instancing a light to an object with one point ( because the  
>>>> light needs
>>>> to be placed inside/stay with a translucent object animated in  
>>>> DOPs)
>>>> I also have other lights in the scene.
>>>>
>>>> I want this one object to only be illuminated by the instanced  
>>>> light and not
>>>> any other lights in the scene.
>>>> However, I'm not sure how to enter this in the light mask.
>>>>
>>>> It seems that if I enter anything other than * I don't get any  
>>>> illumination
>>>> on that object.
>>>> I've tried entering the instanced object and the source light  
>>>> explicitly.
>>>> I've also tried entering * and then eliminating lights with  a ^  
>>>> string ....
>>>>
>>>> but unless I enter a wide open * I don't seem to get any  
>>>> illumination on
>>>> this surface.
>>>>
>>>> Any thoughts??
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Larry
>>>>
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>>>>
>>>
>>>
>>>
>>> -- 
>>> Cheers,
>>>
>>> Peter B
>>>
>>> --No, I am not on Facebook.
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