[Radiance-general] replmarks and mirroring

[Jack de Valpine]

Hi Lars,

If you mirror a marker triangle in cad (for example autocad), then the 
normal ends up pointing the opposite direction. Thus in radiance if you 
use a set of markers that include mirrored and unmirrored triangles then 
some of your instance objects will actually point down. One way to 
resolve this is to use two sets of markers (as previously pointed out in 
another email). If you create a mirrored instance of the object, then 
you are actually reusing the object geometry and conserving memory. The 
way to do this is create an compiled octree version of the object and 
then create an instance that mirrors it appropriately around x y or z as 
follows:

void instance foo.mirror
6 foo.oct -m<x,y, or z> -t xt yt zt
0
0

Since you are simply resuing foo.oct then you conserve the memory. I 
must admit that I have to play around with -m<x,y,z> to figure out how 
the object mirrors correctly and you may need to transform the object to 
get the position to work out with respect to your marker.

-Jack

Lars O. Grobe wrote:

> Hi,
>
> yes, of course you are right. However, the idea is to reuse geometry 
> when possible (and I have hundreds of objects which are placed by 
> replmarks) and stay as close as possible to the cad packages. I wanted 
> to ask as replmarks seams to be just for that goal ;). The integration 
> of CAD and radiance without the need of writing radiance scene files 
> manually is sometimes important... That's why I wonder if it would 
> make sense to use surface normals of the triangles in replmarks - and 
> add mirroring functionality that way.
>
> Thanks+CU Lars.
> -- 
> Lars O. Grobe
> grobe at gmx.net
>
>
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-- 
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