ray3.exe outputs to STDERR, so you cannot simply do this:
ray3 -v 6 test.mi > out.txt
You have to do something like this:
ray3 -v 6 test.mi 2>out.txt
In the above command, 2>out.txt redirects STDERR to the file out.txt.
Or you can do this, which redirects all output (STDOUT and STDERR) to out.txt:
ray3 -v 6 test.mi >out.txt 2>&1
References: