All items referenced are free.
DA may need free membership. BowlRoll does not need membership for this door model.
All clicks are left-click unless stated.

'PMX Editor (English translation)'
https://www.deviantart.com/inochi-p...-v2-0-766313588
Please follow the installation instructions.
It should give a purple-haired Anime icon, open as two windows, 'PMX View' scene and info. Both re-sizeable.

Note upper-right of 'PMX View' window has camera pan/tilt, side-shift, in/out and twirl icons resembling Poser.

'Door everywhere'
https://bowlroll.net/file/271677

Drag preview pic to convenient folder. Rename lonnng name if annoys.
If browser does not auto-translate, you need the BIG orange ' _V_ Download' button.
Click this and save zip to convenient folder.
Don't worry if looks like 'どこにでもドア.zip'
Rename to eg door.zip

Free Bandizip will decode contents' names to correct glyphs, but not neccessary for this model.

Un-zipper of your choice will deliver two PMX files. Don't mind the 'dipthong noodle' names.
19.7 k file with longer name is 'door_dummy'. Rename as such.
20 k file with shorter name is 'door', the one you want. Rename as such.

Drag this 'door' file into either editor window.
Accept import settings' defaults of 'New' and Size = 1, with 'Edge' ticked.

Door may be too tall for 'PMX View' window. Use in/out arrow to frame it.

Click the 'PMX View' window's tool-bar's 'T' button to open a new 'Transform' window.

Door should have two blue spots marking the 'rig/bones'.

Click the one half-way up hinge-line. A red/green/blue 'gyroscope' should open.

Just to right, 'bone list' should highlight #1 and OP. Rotation XYZ should show in colour rather than grey.

Click-drag the green 'Y' button up/down to swing door. (Remember, open towards hinges... )

I have not yet found how to set or read precise angle, say 45º. YMMV.

At top-left in this 'Transform View' window, click on 'File' then 'Update Model (U)'

Accept the default 'morph threshold', whatever that means.

The door in 'PMX View' window now matches the swung door in 'Transform View'.

If you want to 'mirror' this model, in 'PMX View' click 'Edit', 'Mirror Model (M)', accept the 'Confirm' warning.

As-is or mirrored, go to the 'info' window. Click 'File', 'Export', 'Save as Type: Alias WaveFront OBJ File'.

Change any default name to eg Door001.obj, click 'Save'.

Accept default export options for Size = 1 and ticked-edge.

You should now have a ~42 k OBJ file and companion MTL. Note OBJ mirrored L/R to 'PMX View'.

If you want to 'mirror' this model, go back to 'PMX View' click 'Edit', 'Mirror Model (M)', accept the 'Confirm' warning. Then go to 'info' window, File, Export etc, but set a different name, eg Door001m.obj

When you close the PMX Editor, it will warn of unsaved edits. Unless you want to over-write PMX file, click OK.

Either door OBJ should import to Poser at ~3.5% original scale, with 'place on floor' set.

Texture to taste. Material zones are...
m0: Frame.  m1: Door.  m2: Hinges + door-handle.  m3: Hinge pin ??

These doors are not 'rigged', there's no dial to twirl to open/close. But, as low-poly, you could make, import and overlay several ranging from 'closed', 'a-jar', 'sidle' to 'wide', make all but the one you want invisible...

As Kath, my wife, was a 'Shakin Stevens' fan between 'ABBA' and 'Queen' albums, here's a 'Green Door'...

 

   Thank you very much Nik! It is much appreciated Sir