[Radiance-general] the vector of sensor in SVF calculation

[Compagnon Raphaël]

One more thing:
If you have a single surface under the sky, its SVF can easily be calculated as: SVF=(1+cos(a))/2 where a is the tilt angle of the surface (a=0 for a horizontal surface; a=90 for a vertical surface; a=180 for an horizontal surface oriented towards the ground)

You can then check your radiance calculations by comparing your results with this formula.
For instance by printing a graph like this:

bgraph | x11meta
Adata=!"cnt 181 | rcalc -e '$1=0;$2=0;$3=0;a=$1*PI/180;$4=sin(a);$5=0;$6=cos(a)'  | rtrace -h -w -I -aa 0 -ab 1 s.oct | rcalc -e '$1=recno;$2=$1'"
Bdata=!"cnt 181 | rcalc -e 'a=$1*PI/180;$1=recno;$2=(1+cos(a))/2'"
xlabel=tilt
ylabel=SVF

You should see that the two curves totally overlap!

Raphaël