Updates:
I'm working my way through the various Trek bridge chairs, generally working from Ent-A-era chairs forward. I'll be tossing in some originals along the way, though, pegged more or less into that time frame with a couple of notable exceptions. The exceptions will still be patterned after real-world chairs in the vein of actual Trek set pieces.
Ergoform Workseat (Star Trek V and beyond):

Completed.
This has been released.
HÅG Capisco, original model (Star Trek V, Excelsior bridge):

Completed.
This has been released.
TODO:
Canon:
Wise 8WD139LS (possibly a variant, Star Trek: Generations, Enterprise

Star Trek IV bridge chairs (reupholstered from original TMP chairs - yes, I have blueprints!)
HÅG H03 (Enterprise, NX-01 task chair)
Non-canon:
Eva Chair by Ora Ïto
Evolution Armchair by Ora Ïto (will be a variant based on that)
Seat from Model F wheelchair concept by Kwanjun Ryu
Altwork Station
Scoop Task Chair by Blu Dot
Daily Task Chair by Blu Dot
Non-canon, boat seats:
Wise 8WD1007-710 Captains Chair (with alterations)
Ozark Bass Seat
Deluxe Sport Flip-Up Seat (with alterations)
Norsap 1600
Art.No 8720
Todd
Freeport Helm Seat (great alternate TOS seat)
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Although that 2nd looks really uncomfortable.
What software are you using for the rendering?
(And thanks for reminding me of work during my holiday
https://www.marineseating.com/product-category/marine-seat-pedestal-and-footrests/
https://norsap.no/product-category/chairs/n16/
Really nice since it has the drawings with dimensions for almost every type they sell
TBH, I'm a little unlikely to do that era in the immediate future. I'm focused on TMP through pre-TNG (anything that would have blue Okudagrams pre-LCARS, basically), and at lease on collection of far-future stuff (think 50+ years post-Nemesis, likely even post-Picard but pre-Ent-J).
That material will be ported over to the Ergoform Workseat as well as other items I do going forward.
References here:
http://movies.trekcore.com/gallery/albums/tuchd/tuchd0095.jpg
http://movies.trekcore.com/gallery/albums/tuchd/tuchd0120.jpg
Thanks!
I am aware of some segmentation in the base, but that is unlikely to be noticeable in typical usage.
I only noticed it after you mentioned it, so I'm sure it won't be an issue.