I've installed program qcad to /opt/qcad-dir directory. Binaries are in /opt/qcad-dir at all in one place. I had to change native qcad.sh script to use program as alternative (update-alternatives). I added DIR=/opt/qcad-dir to run the program with its libs, otherwise, qcad that run from another directory isn't saw its' libs.
So. I moved all program files into /opt/qcad-dir, then I change qcad.sh to make it possible to run from another directory. I created symlink to alternative. And now it is available to run qcad from anywhere.
Is it more correct way to install program (which stores all binaries in the same dir) system widely?