Can you rotate an area light?

All the examples are just perpendicular, ex:

<0,5,0>,<5,0,0>

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Le 09/12/2013 04:16, Andy a écrit :
> Can you rotate an area light?
> 
> All the examples are just perpendicular, ex:
> 
> <0,5,0>,<5,0,0>

you can specify the 2 vectors as you want, but you must rotate them
before hand.

You can also have a look at "reorient", but that's not the same effect.


-- 
Just because nobody complains does not mean all parachutes are perfect.

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> Can you rotate an area light?
>
> All the examples are just perpendicular, ex:
>
> <0,5,0>,<5,0,0>
>
>
>

Normaly, you use perpendiculat dimention vectors, but they can have any 
orientation you want and don't need to be strictly perpendicular.

If you rotate the whole light_source, it will cause an equivalent 
rotation of the area light's axis.

They can also be made to reorient themselve using the orient option that 
must be used with circular 2 vectors must have same lenght and the same 
number of elements in each directions.


Alain

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Alain <kua### [at] videotronca> wrote:

> > Can you rotate an area light?
> >
> > All the examples are just perpendicular, ex:
> >
> > <0,5,0>,<5,0,0>
> >
> >
> >
>
> Normaly, you use perpendiculat dimention vectors, but they can have any
> orientation you want and don't need to be strictly perpendicular.
>
> If you rotate the whole light_source, it will cause an equivalent
> rotation of the area light's axis.
>
> They can also be made to reorient themselve using the orient option that
> must be used with circular 2 vectors must have same lenght and the same
> number of elements in each directions.
>
>
> Alain

ah.. should have figured that out myself. Sorry for such a not-thought-out
question.

So, we'd end up with something like this:

light_source {
 <0, 24, 10> color rgb<0.88, 0.88, 0.88>
 area_light
 <0,0,10>,<10,0,0>,10,10
 adaptive 1
 jitter
 rotate <25,0,0>
}

it would rotate it 25 degrees on the X axis.

Thanks, guys... once again.
-andy.

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Since I have your attention... Is there any difference between this:
<0,0,10>,<0,10,0>
and this:
<0,10,0>,<0,0,10>

And does this make any difference and/or is it legal:
<0,0,-10><0,-10,0>

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> Since I have your attention... Is there any difference between this:
> <0,0,10>,<0,10,0>
> and this:
> <0,10,0>,<0,0,10>
In most cases, the two are equivalent. If the dimentions are different, 
there will be a difference. It also make a difference if the sublights 
array don't have the same size in both dimentions.
>
> And does this make any difference and/or is it legal:
> <0,0,-10><0,-10,0>
>
>
It should'nt mather if the dimentions are positive or negative. It only 
change the order that the aray of sublights is filled. Just try using a 
negative dimention to see if it work.

When using adaptive, an array of 10 by 10 is not effecient as it can't 
be subdivided correctly, and will be silently changed to 9 by 9 OR 17 by 17.
adaptive will use those dimentions: 3, 5, 9, 17, 33, 65, 129,...
adaptive can take the following values: 0, 1, 2, ...
The value following adaptive is NOT a boolean value, but the minimal 
subdivisions steps to be used.
adaptive 0 start with the 4 corners: 4 samples. No appreciable gain 
under a 5 by 5 array.
adaptive 1 start with the corners and the mid points of the edges and 
the center point: 9 samples. No appreciable gains under a 9 by 9 array.
adaptive 2 use at least 25 samples and adaptive 3 at least 81.



Alain

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