# rtrace -o adds direction to origin

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).