Easy enough to drag an OBJ into my TurboCAD 2016 (TC), use the nimble 3D Booleans to eg 3D Slice apart, re-save as split object...
When it works.
Sadly, when this 'new, improved' OBJ is loaded into Poser, it is often a mess.
Broken faces, artifacts, hair-tear...
D'uh...

I'd got this budget pew+kneeler by francescomilanese from CG Trader
https://www.cgtrader.com/3d-models/...ch-with-kneeler

I needed to slice off parts of a pew to 'book-end' front and back of several rows.
No, the exported OBJs were not 'playing nice'.
They often loaded into Poser like a ST-TOS transporter accident.
And, sometimes, worse...

Yet, the split OBJ file often loaded okay into ($$) 3DOC...

Out of curiosity and, yes, running out of things to try, I re-saved from 3DOC....

Yay !!
Okay, TC had, of course, lost the call to a wood veneer JPG, but that was almost trivial. Fixed in 'Material Room', I was then able to clone the 'intact' pews, the 'seat+back_only', the 'kneeler+stub_front_only'...

FWIW, import pews and parts at ~0.5% original...

The pillars, place-holders for better, in this scene are each a tall Poser primitive cylinder capped / spread by a shorter, wider version...

 

A lot seems to depend on the actual model. I'd managed to find a nice, free arched door-way. Yes, is DS, but door-leaves conveniently supplied as 'Poser friendly' OBJs. I parented them to arch-way, set their 'origins' and 'y-rotate' to swing from shut to ~165º.
https://www.Renderosity.com/freestu...zceneic-route-4

Okay, there were nice plates and grab-rings on door, but needed a lock...

After much hunting, I found a budget model of a traditional 'rim lock', set to work.
https://www.cgtrader.com/3d-models/...handle-and-lock
I did not have to 'Boolean' much, everything was already sub-divided to logical groups.
As there were no 'fixings', I added 5+2 small brass hemi-spheres, think 'mirror screws' with screw-on caps. Also prevents decorators varnishing / painting over lock's screw-slots every decade for a century: Been there, sawn / chipped such free...

'Some assembly required'. The lock components' Poser import scale was 0.05%, but this was internally rounded to 0.1% when it offers next one. After some confusion, I had to remember to change the '0.1 %' shown to necessary '0.05 %'.

So, piece by piece, I re-assembled the lock. Position, scale for door thickness, parent to case or striker, which were parented to door leaves. I also set 'translate' ranges to draw the bolt or latch.

The key is too short, I'll have to edit that...

A further 'gotcha': Although the doorway's 'front view' rendered well, Poser reckoned the 'reverse' view was 'too something', refused to render with my twin GPU cards. After a couple of blanks, I shrugged and sent render-job to 'Box'...

My apologies for terse text as I've been up half the night with first ghastly cold of season: streaming sinuses, coughing up snot etc etc. By curious coincidence, this morning's post brought an invitation to book my Covid booster and 'Seasonal Flu' vaccinations...

 

 

I found two, but one looked wrong, too 'modern'.
https://www.cgtrader.com/3d-print-m...ide-barrel-bolt

Another was 'chunky', looked 'traditional', would scale well.
https://www.cgtrader.com/3d-models/...part/tower-bolt

It came as IGS, which TC happily imported.

I managed to separate bolt and case, the former destined to be 'brass', the latter 'black oxide'. Six brass 'roundheads' gave neat fixings.

But, there, it all began to go wrong. I have persistent problems setting 'origin' for imports, so they can be aligned on rotation axes etc. Four times, I set bolt slide limits to dial up/down, dial bolt turn etc. Four times, that bolt vanished into the distance when I tried to 'parent' it...

My 'ghastly' cold has subsided to 'miserable', the joint pains have eased. But, I could not see what was wrong with the bolt.
In the end, I just shrugged, saved the scene, rendered...