Right Angle Route/Slot in Padstack?

There is no provision to do Path Operations for routing boards in the Cadence tool so you will have to go another route instead.

Create the pad using a shape on all layers you need. Inside the pad you could do a void to represent what the actual slot will look like.

Call out on your Fab Drawing what you wish to have routed out. At the board house what they will do is basically create a path for a specific bit so your board can be routed out.

Hope this helps.

I have found that the best way to do this is with two pins:

You could always draw the outline of the slot using Board Geometry / Cutout then on the inside draw the actual route path using Board Geometry / NCRoute_Path. Make sure this line is drawn at the actual thickness of the slot required. Also ensure you have keeppout areas drawn to keep the slot clear of copper / tracks etc. When you post process the NCRoute_Path is included in the Manufacture - NC - NC Route file.

I think I'm going to go this route.  It creates a DRC, but otherwise, is the most straight forward and least likely to get messed up in manufacturing.  Thanks for the tip Dave!

Steve, thanks for that been along time since I used that "Foggy Memory" 

This works great. Verifying in a cam editor produces excellent results.

In the pic you can see the results of a test route in a copper pour. The area in red is the actual tool that would route out the board to create the slot.
This particular example just had a 50 mil curved line on the board geometry NC Route path layer. So yep lots of possibilities to pretty much route out any pad or area etc.

Thanks.