# mkillum useage with large scenes

**URL:** <https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736>\
**Category:** radiance-general\
**Created:** [March 16, 2006, 5:59pm UTC](https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736 "2006-03-16T17:59:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Lars\_Grobe](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/lars_grobe/32/469_2.png) [@Lars\_Grobe](https://discourse.radiance-online.org/u/Lars_Grobe)\
**Post date:** [March 16, 2006, 5:59pm UTC](https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736/1 "2006-03-16T17:59:14Z")

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Hi group,

while I have been using mkillum for a while now, I need your advice on  
its application again.

I have a large scene, and so far, I had an external file containing only  
the illums. So I could use the external file as mkillum's input and run  
it with the (large) scene's octree:

mkillum large\_scene.oct \< only\_illum\_faces.rad \> only\_illum\_sources.rad

than, later

oconv large\_scene.rad only\_ilum\_sources.rad \> full\_scene.oct

(eh, I could have used oconv -i large\_scene.oct only\_illum\_sources.rad \>  
full\_scene.oct, right?)

But now I have to change the structure of my scene a bit, and it gets  
difficult to keep the illums in an external file. So, given that  
large\_scene.oct is made of large\_scene.rad, could I equally use

mkillum large\_scene.oct \< large\_scene.rad \> only\_illum\_sources.rad

given that I set the right -i=illummodifier at the beginning of  
large\_scene.rad? Will this use much more ressources? As I understand,  
the only difference should be file access, as the full file will be sent  
to mkillum instead of only the faces that are to be converted.

If you wonder why I do not simply try, it is because my model is build  
by some scripts I have to change, and I wonder if it is worth it and  
possible at least.

TIA+CU, Lars.

P.S.: Concering the link I sent, now I know that I REALLY missed what I  
should have seen on the workshop ☹

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**Author:** ![Greg\_Ward](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/greg_ward/32/471_2.png) [@Greg\_Ward](https://discourse.radiance-online.org/u/Greg_Ward)\
**Post date:** [March 16, 2006, 11:26pm UTC](https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736/2 "2006-03-16T23:26:46Z")

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Hi Lars,

> I have a large scene, and so far, I had an external file containing only  
> the illums. So I could use the external file as mkillum's input and run  
> it with the (large) scene's octree:
> 
> mkillum large\_scene.oct \< only\_illum\_faces.rad \> only\_illum\_sources.rad
> 
> than, later
> 
> oconv large\_scene.rad only\_ilum\_sources.rad \> full\_scene.oct
> 
> (eh, I could have used oconv -i large\_scene.oct only\_illum\_sources.rad \>  
> full\_scene.oct, right?)

(Yes.)

> But now I have to change the structure of my scene a bit, and it gets  
> difficult to keep the illums in an external file. So, given that  
> large\_scene.oct is made of large\_scene.rad, could I equally use
> 
> mkillum large\_scene.oct \< large\_scene.rad \> only\_illum\_sources.rad
> 
> given that I set the right -i=illummodifier at the beginning of  
> large\_scene.rad? Will this use much more ressources? As I understand,  
> the only difference should be file access, as the full file will be sent  
> to mkillum instead of only the faces that are to be converted.

You would have a line such as:

#@mkillum i=illummodifier

in your file. However, this would output your entire scene, only modifying the surfaces with that modifier. You could have to take the entire output of mkillum in this case as the input to your new octree. There are ways around this using the o= setting, but they're complicated.

-Greg

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**Author:** ![Lars\_Grobe](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/lars_grobe/32/469_2.png) [@Lars\_Grobe](https://discourse.radiance-online.org/u/Lars_Grobe)\
**Post date:** [March 19, 2006, 4:29pm UTC](https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736/3 "2006-03-19T16:29:32Z")

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Hi!

Thank you for the help, mkillum is somehow still one of the radiance  
secrets.

Ok, I am trying that now. I am curious about the "complicated way" using  
-o settings for mkillum. Still, now I want it to work first 😉

One question arised now. I had been filtering my scene for the  
mkillum-faces' modifier, replacing it by void, and than run mkillum with  
-i=void. I would prefer not to filter, but still, I need a modifier that  
will actually never be used to define my mkillum-faces. Can I define an  
alias to void for that? E.g. void alias mkillum\_faces void? So that  
before I run mkillum, these faces just are not visible, but I can still  
run oconv on the scene? Or should I better use a dummy material for them  
(e.g. a glass with 100% transmittance? So far I like to be able to run  
rvu on the scene before using mkillum, so I prefer not to have some  
thousand of these faces with a dummy modifier, but I guess that alias to  
void could cause problems?

Thank You, CU Lars.

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<div class="post-metadata">

**Author:** ![Greg\_Ward](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/greg_ward/32/471_2.png) [@Greg\_Ward](https://discourse.radiance-online.org/u/Greg_Ward)\
**Post date:** [March 20, 2006, 5:59am UTC](https://discourse.radiance-online.org/t/mkillum-useage-with-large-scenes/3736/4 "2006-03-20T05:59:26Z")

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Hi Lars,

The alias type demands a valid (previously defined) identifier, and will not accept "void" in the current version.

You are introducing too many artificial constraints, such as requiring your scene files to have everything intermingled, with illum surfaces visible beforehand then invisible afterwards, etc., etc. Separating the surfaces you want to render and treat differently in separate files is by far the easiest way to go. You are making life unnecessarily difficult by bundling it all together in one stream.

-Greg

> **···**
>
> > From: "Lars O. Grobe" \<grobe@gmx.net\>  
> > Date: March 19, 2006 8:29:32 AM PST
> > 
> > Hi!
> > 
> > Thank you for the help, mkillum is somehow still one of the radiance  
> > secrets.
> > 
> > Ok, I am trying that now. I am curious about the "complicated way" using  
> > -o settings for mkillum. Still, now I want it to work first 😉
> > 
> > One question arised now. I had been filtering my scene for the  
> > mkillum-faces' modifier, replacing it by void, and than run mkillum with  
> > -i=void. I would prefer not to filter, but still, I need a modifier that  
> > will actually never be used to define my mkillum-faces. Can I define an  
> > alias to void for that? E.g. void alias mkillum\_faces void? So that  
> > before I run mkillum, these faces just are not visible, but I can still  
> > run oconv on the scene? Or should I better use a dummy material for them  
> > (e.g. a glass with 100% transmittance? So far I like to be able to run  
> > rvu on the scene before using mkillum, so I prefer not to have some  
> > thousand of these faces with a dummy modifier, but I guess that alias to  
> > void could cause problems?
> > 
> > Thank You, CU Lars.