[Radiance-general] obj2rad splitting planar surfaces?

[Greg Ward]

Hi Randolph,

Seems obj2rad has an initial test to determine if a polygon has specified normals.  If it does, then it breaks it into triangles.  Once it looks at the triangles, it then sees if the normals actually require interpolation or not.  If they don't, then it doesn't specify a texture, but they still get output as triangles.

Is it a problem?  Just take off the normals if it is.

Best,
-Greg

> From: "Randolph M. Fritz" <RFritz at lbl.gov>
> Date: March 22, 2012 11:14:31 AM PDT
> 
> Am I missing something?  It looks like obj2rad is splitting a planar rectangle into two triangles.
> 
> I think this OBJ file describes a single vertical rectangle:
> -----------------------
> # Rhino
> 
> mtllib one_plane.mtl
> g IllumSrc__Center
> o FirstIllum
> usemtl Default
> v 81.44685363769531 1 42
> v 81.44685363769531 1 90
> v 35.44684982299805 1 42
> v 35.44684982299805 1 90
> vt 0 0
> vt 0 1
> vt 1 0
> vt 1 1
> vn 0 1 0
> vn 0 1 0
> vn 0 1 0
> vn 0 1 0
> f 4/4/4 2/2/2 1/1/1 3/3/3
> -----------------------
> 
> And this obj2rad file describes two triangles:
> -----------------------
> # obj2rad one_plane.obj
> # Rhino
> 
> Default polygon FirstIllum.1
> 0
> 0
> 9
>     35.446849823                  1                 90
>    81.4468536377                  1                 90
>    81.4468536377                  1                 42
> 
> Default polygon FirstIllum.1
> 0
> 0
> 9
>    81.4468536377                  1                 42
>     35.446849823                  1                 42
>     35.446849823                  1                 90
> 
> # Done processing file: one_plane.obj
> # 19 lines, 18 statements, 1 unrecognized
> -----------------------
> 
> 
> Meantime, I'd better come up with a script that produces the proper output.
> -- 
> Randolph M. Fritz