[Radiance-general] rcalc if, else, then

[Dan Fitzpatrick]

HI Group,

This is bugging me and possibly easy to resolve but I'm struggling.  I am testing materials and their reflectance and need to use rcalc to help me identify which materials my ray is hitting.

Using a simple mirror material I have created a blue material with close to 0 red and green.  I have fired a ray in the direction of this material and now I need to determine whether it is a hit.  Using -ab 0 I get the following result:

5.475634e+01	5.475634e+01	2.737817e+02

My material is below:

void mirror wall
0
0
3 	0.2 0.2 1

I'd like to use rcalc to tell me whether I am hitting the material or not.  I was thinking of something like 

rcalc -e 'if($1=$3,$1=1,$1=0)' test.dat > test_res.dat  simply to give me a Boolean dat file of either 1 or 0.

But obviously that doesn't work so can someone help me with a possible solution?  I've trawled the mailing list to no avail so far.

Many Thanks

Dan