Yes, the lower frame is exactly the whole build area
. One runs into all new problems when using the whole space.. but otherwise the flap would be too small for my big cats (Bengals).
Rigid ink ASA prints like a charm, when you have an enclosure. One just encounters light warping (especially at the 90 degree corners, could be prevented with round corners). With area for a brim I think one would have no warping at all with an enclosure.
Only problem I had was with layer cracking at the tunnel. I think that could be solved with one or two perimeter walls more.
I have parts outside since spring out of asa, all look like new. UV light and moisture do not matter at all.
And it can be polished and is great for mechanical parts.
Would be my everyday goto filament, just two problems: - fumes during printing and the need for an enclosure. And just few colors..