If you download vaa3d directly and run it, you will get some version errors. This can be done as follows: first download the pre-compiled Qt 4.7.1 from https://home.penglab.com/tmp/qt7.tar.gz and extract it to the /usr/local/Trolltech directory; download Vaa3D 3.458 from GitHub; go to vaa3d64.app package contents, go to macOS and run vaa3d64 inside. This will allow you to run vaa3d.