[Radiance-general] rtrace -oo adds direction to origin

[Axel Jacobs]

Confusing, I know

I am using 3.7.2.

I am trying something like:

cnt 2 3| rcalc -e '$1=$1;$2=$2;$3=1;$4=0;$5=0;$6=1'| rtrace -I -ab 1 -ad
64 -h -w -oov axel.oct| rcalc -e '$1=$1;$2=$2;$3=$3'
0       0       2
0       1       2
0       2       2
1       0       2
1       1       2
1       2       2

Compare this to:

cnt 2 3| rcalc -e '$1=$1;$2=$2;$3=1;$4=0;$5=1;$6=0'| rtrace -I -ab 1 -ad
64 -h -w -oov axel.oct| rcalc -e '$1=$1;$2=$2;$3=$3'
0       1       1
0       2       1
0       3       1
1       1       1
1       2       1
1       3       1

radiance 3.7.2 seems to add the direction vector to the ray's origin at
its -oo output.

Now try:

cnt 2 3| rcalc -e '$1=$1;$2=$2;$3=1;$4=0;$5=3;$6=0'| rtrace -I -ab 1 -ad
64 -h -w -oov axel.oct| rcalc -e '$1=$1;$2=$2;$3=$3'
0       1       1
0       2       1
0       3       1
1       1       1
1       2       1
1       3       1

Aha! It is in fact the _normalised_ direction vector which it adds.

I've done similar rtrace jobs lots of times before, but this behavious
seems to be newly introduced in a recent release. -oo always used to spit
out exactly the input, not (input+direction).

Please advise.

Axel