a slight aside, i'd like to have some simple tool (standalone even?) to convert back and forth between PTN and MID formats - i wonder what's in PTN that's not in MID?
Here's
some info on it that's nearly 10 years old. The "automation" part always intrigued me, but there was never enough documentation to fully exploit it. The audio part didn't surprise me at the time, because of the way that Project5 treated all clips equally. A pattern file was always referred to as a "superset" of MIDI in Project5-speak. I'm thinking that there may be some omissions as well (program changes? flavors of aftertouch?).
There was a rumor at one point about a standalone convertor between .ptn and .mid. Nothing ever materialized after some promising initial discussion with Cakewalk personnel. In any case, some expansion of Sonar's pattern file treatment seems like it could require minimal effort.
Instead of working in legacy P5 software, then importing / exporting back & forth with Sonar, we could use Sonar itself (and all of the current MIDI transformation features) to create a .ptn file. Since the per-track arpeggiator is now a sole property of Sonar, that only makes sense. I can tell you that it was a real PITA to swap programs (both 32-bit) while making the Alesion Arp files. I wouldn't look forward to trying that again using 32-bit legacy abandonware and 64-bit Sonar X3.
Standalone; integrated ... it really doesn't matter to me. But if a large part of the arpeggiator feature set is to create your own pattern-based .arp presets, there ought to actually be a way to do it without jumping through hoops.