Updating this for future travelers because this thread gets linked a lot, some complementary info to my post in the first page of this thread.
Things changed a bit with PTVS 2.2 and VS2015, I couldn't get it to work by attaching to motionbuilder.exe alone, only by remote debugging to my localhost:5678. Like this:
And you need to click "Refresh" in the bottom, NOT "Find..." right next to the address field. Yes, I lost quite some time just because of that...
Lastly, a little sample code:
I couldn't get a small script with a for loop to trigger a breakpoint without ptvsd.wait_for_attach(), but maybe bigger script/tool with an UI waiting for some kind of input might work without it.
For intellisense on the other hand nothing changed. BUT, PTVS currently does not support a huge library of modules, tools, etc. If you add too much stuff into your project or search paths, intellisense might just stop working without any error whatsoever. Links to logged bugs in github: