It would be messy and impractical in my opinion. You would have to use the Mentor translator program to convert your Altium Designer schematic (and/or netlist) and board to PADS. You would then have to do the cleanup that is always required when conversions like this are done. You could then route the board, save the file, and use the Altium Designer Import Wizard to bring the results back into Altium Designer.
You would be better off sticking with one EDA program. If you want an improved router to use with Altium Desginer, you can use either Cadence Specctra, or Electra Router (see https://www.connecteda.com/doc/Autorouting Techniques.pdf ).
It is question for us, " how much of your design is auto-routing?" Manual routing of big digital design, with many devices and many pin-count, is not a easy job! For a sample 10-layer moderate board, takes more than 3-weeks with hard working. On the other hand, we all know that autorouting will not give an acceptable result.
Checked out Electra seems like you can only auto-route and not interactively route.
Ill have a look at specctra. What do you use for auto-routing House_Cat?
Both Electra and Specctra are autorouters. You do your interactive routing in Altium Designer before and after the autorouter is run. You interactively route and lock critical signal paths, autoroute, then interactively route what the autorouter cannot properly finish.
A human being is the most efficient router ever conceived. Although it takes longer to manually route a board, the results are far superior to anything an autorouter can achieve.
In cases where there is a complex board where the customer prefers speed and there are not too many critical signal paths, I use Specctra. Altium has a direct import/export capability for the Specctra router.
Any autorouter requires carefull setup of routing rules before beginning. It can take a week or so just to set up the router instructions before starting autorouting. It isn't a tool that lets you just mindlessly route a board. The Electra link I listed above is to a document describing how to set up the router for Protel/Altium autorouting.
I usually hand route everything anyway. I have a couple larger designs I may be working on and I was interested in a fast efficient auto router for non critical signals.
When I translate the AD PCB benchmark over to PADS, pads can not only route the board with 100% completion in less than 30 mins, but also produces about 1000 less vias with better quality routes. I have yet to finish the benchmark in AD, I get too impatient and stop it, 80% completion in over 2 hours and still going on a 3+ GHz P4.
I tried the electra demo and that router is very fast as well. I can't really say it produced the same quality routes as PADS but it was still a lot faster than AD. Makes me wonder why the Situs router is lacking so much even at their own benchmark.
I guess Ill stick with hand routing until Altium decides to upgrade their router to make it more on par with the competition.