Modular Castle / Fort (DND / TTRPG)

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This is a Modular Castle / Fort based on "Fort Nandar" from Storm King's Thunder (see my note below for more info about this and the history of this project).

I've created a bonus hollowed "miniature version" of this Fort and posted it over on my Patreon. This is a nice little prop for epic scale combat, a desk ornament or for a fish tank. You can get it over on my Patreon here.

This print is designed to be completely supportless and modular. It can be printed at the full height or in short "flat stack" sections which are much more playable but maybe less exciting aesthetically. The footprint of the entire structure is 310mm x 310mm x 190mm and can comfortably sit on most any play area without overwhelming other props. The design is compact enough that you could easily have a couple of these on your table and stage a battle between two of these forts customized to the player's specifications.

This structure is comprised of 3 floors with modular sections and internal walls. Each floor has a 25mm grid across four main sides - I've split those sides into a top and bottom parts so you can print a "flat stack" castle or print the upper wall sections w/ windows and sockets for doors etc... There is also a rooftop with crenels for cover. The parts have a set of pins so they can socket into each other and the floor sections have holes for dowels that can be slid in and glued as needed. You can print as many or as few layers of this as you'd like to suit your campaign needs.

Current Parts included:

• Floor 1 (F1) - includes a flat baseboard and a variant with the front door, walls only have a single window up high which lets in light but limits visibility to the interior, walls slats allow for 2 types of interior walls

• Second floor (F2) - includes a bevelled baseboard (note that this was removed with the release of v2), the walls have 2x windows, up high and another set at eye level, walls slats allow for 2 types of interior walls, additionally there is a variant that includes a hole for a staircase

• Rooftop floor (F3) - Crenels along the wall with the same bevelled baseboard as F2, there is a variant for stairs on this as well

• Internal Walls - There are currently 3x versions with no doors - I'm working on a supportless door design to go in here but for now these use a supportless open door design

• Staircase - I used the untextured version from my staircase collection with some slight adjustments to fit comfortably in the stairholes

• Front door parts - The two sides of the front door which can be popped in or out of the F1 top wall sections *** Note that the fit on these is finnicky so I will be updating with a new version soon ***

• Pins - for the sides of the floor sections I could add something like OpenLock instead of these but for now this is a really simple way to stick the parts together

For printing I've included some 3mf files. You can print the FULL castle or the "flat stack" version of it. For print settings I'm recommending 2 wall loops and 5% infill density. Printing the "flat stack" version of this fort should take about 1.2kg of filament and if you add the exterior walls it'll be another 800g so about two spools. Printing at 0.28mm layer height should be fine since this is untextured but for any future textured versions you'll want to print at 0.2mm or lower to preserve detail.

Project Updates (Patreon might be more up to date)

Mar 2, 2026 - Added V2.2 Plain Fort files

Test printing on the textured version is done and I found the source of a fit issue so I've applied that fix to the plain files and updated them here. To avoid confusing versions I've removed the v1 and v2.0 files. They're still available on Google Drive or if you really want them feel free to reach out and I'll share them with you but these 2.2 files are better. I've also removed the interior walls and doors while I do some updates on those - thanks for your patience here!

• Changelog

  • Fixed fit issue (top dowels were slightly misaligned on one side)

  • Added extra open lock clips to the stair parts so that they are more secure

  • Removed some of the destructive "flattening" that was being done so the structure is a tiny bit larger (but still fits with parts V2)

  • Added a slight bevel to all straight edges

  • Temporarily removed the v1 doors and interior wall files while their v2 versions are in development

Feb 22, 2026 - V2 Update

I've removed the initial fort wall files and will be updating the interior walls soon. This new version introduces some breaking changes like increasing overall size and introducing OpenLock clips in place of the bottom dowels. The bevels on the 2nd and 3rd floor baseboards were also removed since this introduced extra complexity without adding much more value. This version is also compatible with the textured variant that is an exclusive model.

The original files are still available on the dedicated Patreon post on this fort project here

Jan 29, 2026 - First Publish

I've finally made some solid progress on my Fort Nandar project here from June of last year and I'm publishing the first complete version of it today. I spent much of January 2026 building a system with Geometry nodes to create the exterior walls, grid flooring, print in place doors, dowels + pins to hold it all together. After a TON of test printing I'm happy to say that the untextured version is in a "publish worthy" place and something you can print for your games. I'm still working on this so there should be some version updates over the coming weeks etc... but the new parts should be compatible with what is shown here.

Here is the original version of the Fort for reference: https://www.thingiverse.com/thing:7062060

This is based on "Fort Nandar" from the Storm King's Thunder adventure. In there it's in ruins but it seemed like a really neat structure and something that I wanted to try making so this is the result. The actual Fort Nandar has a slightly different profile and would be twice as big as this one. I might try creating, publish + slice apart something that like in the future but this ~50% scale version is a bit more playable and budget friendly - you can pretend that each square in this is 10ft and it's a pretty close proxy to the real deal.

I've completed my quest for 1000 models in 2025 so now I'm trying to decide whats next - I'm actively asking my Patrons what kind of models that they want to see. You can follow along with me on Thingiverse, Printables, Cults3d or join in on the discuss on Patreon here (as well as get codes for exclusive downloads on Cults3d). If you have something that you need or a custom model like this that you want then let me know and let's make it!