That seemed to be one of the more prominent features of the new release.
Admittedly, I've never used r3d for dynamic analysis. Or really for anything other than small/non-building structures and misc frames, and wood structures (apartments) where we're comfortable using static analyses. I suspect I'm missing out on probably 50% of the capability of r3d... We've always used RAM SS for such models (steel/concrete). And double-admittedly, dynamics is probably the biggest hole in my engineering knowledge. Suffice it to say I know what you're talking about generally, but I wouldn't be able to make any meaningful assessment of what I'm looking at if I went through the exercise
I did look through the new files that came with v20 and did not see any verification problems for the new feature you're describing. But nonetheless I'd be curious to compare the results with the AISC benchmarks, and also compare against some samples in RAM SS, just for S's & G's.
Otherwise, I've been toying around with a basic catwalk model in r3d all day and have been pleased with some of the enhancements/creature comforts they've been working on. Save for a single error I keep getting about shear modulus of 'rigid-column' material. But I suspect that has to do with my heavily modified databases/redesign lists/etc.
Still waiting for the re-introduction of flexible diaphragm design in floor>3d models. They did fix a (rather massive) bug relating to flexible diaphragm load attribution in models with discontinuous diaphragms. E.g., an apartment building with a big courtyard in the middle of it where diaphragms are defined around the perimeter of the 'courtyard hole', the 'transient area load' type attribution of lateral forces to lateral elements completely neglected the giant void in the middle of the building. Bad explanation... but essentially the inner walls surrounding the courtyard would still have the entire flexible load from the courtyard 'void', plus the true tributary load from the real/existent flexible diaph regions attributed to them. Which resulted in extremely conservative (well...just completely incorrect) results. Haven't verified it yet though.