Forest City Layers Get the files

Forest City Layers · Made for my own armour

Modular Armour Attachment System

A printable system for joining flexible straps, mounting them inside armour, and choosing where your build locks together or releases magnetically.

Complete system · CultsFree Standard starter · MakerWorld

Forest City Layers Modular Armour Attachment System

Digital files to print yourself. CA$7.99 introductory price for the complete system.

Ready-made kits — coming soon

Real green printed joiner bases and separate caps, from left: L, straight, T, Y and X.
Real printed joiners and caps. Left to right: L, straight, T, Y, X.
71 printable variantsSTL + matching 3MFMagnetic + non-magneticStraight · L · T · X · Y

My story

I just wanted my armour to stay together.

I was building my own 3D printed armour, and managing all the separate pieces was frustrating. I tried tape, Velcro, hot glue and other fixes.

So I started designing a magnetic TPU strap for myself. One connector became two families, different straps and bases, locking mounts, joiners and a mounting system I could build around.

“It's got magnets, it uses TPU, and everything kind of locks together.”— Dylan, in my workshop

Hear the story in my own words. The video uses my real voice and workshop footage.

Press play for the story. Sound on. Choose your download below.
Read the spoken transcript

“I've been struggling to build a 3D printed Iron Man suit. So, after all of that failed, I decided to use Fusion 360 to make my own system. And it's got magnets, it uses TPU, and everything kind of locks together.”

Real seating, flex and an unmeasured hand tug. Silent video.

See it work

Connect. Flex. Release where you need to.

The magnetic plug seats in its matching TPU base. The strap bends between your printed pieces, while each mounting point stays accessible.

  1. Seat the plugMatch the family and magnet polarity.
  2. Let the TPU flexChoose the length and style for your layout.
  3. Peel to releaseSupport the base and lift near the plug neck.

Release one connector locally instead of pulling from the middle of the strap. No numerical load rating is claimed.

Strap joiners

Five shapes. Build the route you need.

Straight, L, T, X and Y joiners give you different strap junctions. Each shape has its own matching base and cap/lid: ten printable variants in total.

Two straps placed in the open straight joiner with its separate cap above.
Straight joiner

Two straps in line.

A matching base and cap/lid. Choose the shape for your strap layout and check your printed fit.

See cap seatedReal printed Straight joiner with cap seated over the straps.
Two straps in an open L joiner with its separate cap.
L joiner

Turn the strap route.

A matching base and cap/lid. Choose the shape for your strap layout and check your printed fit.

See cap seatedReal printed L joiner with cap seated over the straps.
Three straps placed in a real printed T joiner with its separate cap.
T joiner

Branch in three directions.

A matching base and cap/lid. Choose the shape for your strap layout and check your printed fit.

See cap seatedReal printed T joiner with cap seated over the straps.
Four straps placed in a real printed X joiner with its separate cap.
X joiner

A four-way junction.

A matching base and cap/lid. Choose the shape for your strap layout and check your printed fit.

See cap seatedReal printed X joiner with cap seated over the straps.
Three straps placed in a real printed Y joiner with its separate cap.
Y joiner

An angled three-way junction.

A matching base and cap/lid. Choose the shape for your strap layout and check your printed fit.

See cap seatedReal printed Y joiner with cap seated over the straps.

These photographs show each joiner with Standard strap ends, open and with its cap seated. Keep the base and cap/lid together by shape and check the exact strap fit. The initial torso wear test is a separate four-strap setup; it does not establish that every joiner shape has been installed or worn.

Standard vs Mini

Two families. The same idea.

Choose a size for your available space, then keep its TPU straps and bases together.

Four assembled Standard bridges on a pale background.
Standard

The full strap selection.

Three base layouts, three flat strap styles and the FlexCord option.

  • Flat straps: 60, 80, 100, 120 and 160 mm
  • FlexCord 5 mm: 100, 140 and 180 mm
  • Eight magnets for one strap plus two bases
Mini flat strap beside two Mini M2 bases.
Mini

A smaller connecting footprint.

Two base layouts and an 8 mm flat strap for more compact spaces.

  • Flat straps: 50, 75 and 100 mm
  • One-mount and two-mount bases
  • Four magnets for one strap plus two bases

Match Standard with Standard, Mini with Mini. Both families use the same PLA post/ring mounting interface and 8 × 2 mm magnets. Check neighbouring mounting footprints before committing to a layout.

Strap options

Magnetic and non-magnetic strap options.

The release has 21 magnetic strap variants and 25 non-magnetic variants. Flat Slim, Flat Standard, Flat Wide, FlexCord and Mini options let you plan the route between mounting points.

Four real printed Mini straps arranged on a pale background.

Mini straps

Four real printed examples from the Mini family, for compact connection layouts.

Four real Standard flat strap lengths with print texture visible.

Flat Standard

The Standard starting point. Five named lengths from 60 to 160 mm.

Wider Standard flat straps viewed at an oblique angle.

Flat Wide

A broader Standard web. Five named lengths from 60 to 160 mm.

Three assembled Standard FlexCord bridges.

FlexCord

Standard connector ends with a 5 mm cord. 100, 140 or 180 mm.

Mini Flat 8 mm comes in 50, 75 and 100 mm. The non-magnetic selection also has four solid locking long straps: 200, 240, 280 and 320 mm. All four retain EXPERIMENTAL in their filenames. This label remains part of their supplied status; the initial four-strap torso test does not change it. Lengths follow the filenames; check the actual fit before printing a batch.

Three separate real-photo crops showing Standard S1, S2 and S3 mounting layouts.
Standard S1, S2 and S3, shown in separate real-photo crops.

Base options

One, two or three mounting points.

Use the layout that fits the inside of your shell and leaves room to reach the joint.

StandardS1 · one mount
S2 · two mounts
S3 · three mounts

MiniM1 · one mount
M2 · two mounts

Five PLA footprint shapes give you different pad outlines: Standard Round, Compact Round, Compact Square, Large Square and Rounded Triangle.

For the close Standard S3 layout, choose Standard Round, Compact Round or Compact Square. Larger neighbouring pads need a clearance check.

Close view of black printed straps and installed mounts inside the white printed torso armour.
Real installed components inside my printed torso.

Locks + releases

Choose where the connection stays together.

A locking base and its matching hood provide a retained strap mounting point. The release includes Standard S4 and Mini M3 base/hood pairs. Keep each hood with its matching locking base.

Magnetic straps and bases give you a local removable connection. Non-magnetic straps provide strap options without embedded magnets; choose the geometry that matches your layout.

Joiners handle the strap junction. Stitch mounting posts and the ring handle attachment to the printed shell. Dry-fit the complete connection and leave enough room to reach it.

Match Standard components with Standard and Mini with Mini. Photos show specific assemblies; verify your own combination and clearance before printing a batch.

Snap-Fuse mounting

Start with a snap. Fuse only when you're ready.

The PLA post and F/Firm retaining ring secure the TPU mounting ear. Choose a serviceable snap joint or optional permanent fusion. The magnetic strap stays removable in either mode.

Finished white post and retaining ring beside the black Standard TPU strap/base.
A real printed post/ring joint. The ring is already seated.
  1. Attach the bare PLA footprintUse a suitable adhesive or PLA pen stitching through the footprint's open slots. Let it cool fully before adding TPU.
  2. Place the TPU base over the postKeep its mounting ear flat on the protected seat.
  3. Press the F ring straight downSeat it over the retaining bead, then check that it holds. Test one joint before printing a batch.

The included F/Firm ring is the creator's physically tested fit. Printer and filament differences still matter.

Mode A

Snap only · serviceable

Leave the ring unfused while you check your layout. Release it gently at the split/service opening when you need to service the base. Replace a damaged ring.

Mode B · optional

PLA pen fusion · permanent

Feed fresh PLA into the top ring cup/channel. Keep the surrounding TPU seat, ring split and solid end lands clear. Let it cool fully, then treat the post/ring joint as permanent.

Footprint stitching attaches the bare post to your shell. Top-channel fusion joins the seated ring to the post. These are two separate steps; keep fresh PLA off the TPU.

View the illustrated Snap-Fuse instructions
Actual-CAD Snap-Fuse instructions: TPU over post, ring pressed down, then serviceable snap-only or optional fresh PLA in the top channel for a permanent joint.
Actual CAD with illustrative fresh PLA. Open full-size instructions.
See mounting footprint styles
Four white PLA mounting footprint styles printed on a textured plate.
Four of the five available footprints shown as real prints.

Embedded magnets

Pause. Add the magnets. Resume.

The printer seals 8 × 2 mm magnets inside the TPU. Set the pause yourself in your slicer.

  1. 01

    Print the open pockets

    Use 0.20 mm for the first layer and every following layer.

  2. 02

    Check before closing

    In Preview, confirm the pockets remain open at the pause.

  3. 03

    Place magnets flat

    Check polarity against the matching part. Keep magnets clear of the nozzle.

  4. 04

    Resume and cool

    The next layer begins closing the pockets. Let the part cool before handling.

Pause before the magnet pockets close.Find the first cavity-closing toolpath in your sliced Preview.

Add and verify a pause while the pockets are open, before the closing layer starts. The exact layer depends on the part, orientation, scale and slicer settings. Check polarity against the matching part before resuming.

Installed + worn

From the bench to my own torso.

I installed the system inside my printed torso and tried an initial four-strap setup while wearing it. That is the initial wear-test evidence for this build. It does not establish performance for every variant or joiner.

Dylan wearing the white printed torso armour during the initial four-strap setup trial.
Initial four-strap torso wear test. Real wearer photo.
Current interior of the white printed torso with visible black straps and installed mounting points.
Current installation layout, photographed later with additional lower straps. Separate from the initial four-strap trial.

Plan your attachment points, check access from inside the shell and test one small assembly. This is personal build evidence without a numerical load rating or a claim of universal compatibility.

Real printed selection of Standard and Mini straps, bases, hoods and mounting parts.
A real printed selection of straps, bases, hoods and mounting parts.

What is included

The full modular system.

71printable variants
71 STL + 71 matching 3MF files
  • 10 joiner variants: five bases and five caps/lids
  • 4 locking base and hood variants
  • 5 magnetic bases
  • 21 magnetic straps
  • 25 non-magnetic straps, including four EXPERIMENTAL long straps
  • 6 stitch mounting variants: five footprint posts and one ring

142 model files represent 71 printable variants. STL and 3MF are matching formats of the same parts. The dated release includes START HERE and the inventory. Digital files only; magnets, filament and physical parts are not included. Personal, non-commercial use under the listing licence.

Print it yourself

Start with a bridge. Plan the whole system.

Both downloads are digital files. Print the parts yourself and add filament and magnets.

Free · MakerWorld

Standard starter

The existing limited four-design Standard starter: S1 base, Flat Standard 60 mm strap, Standard Round post and F/Firm ring. It covers the first magnetic bridge.

STL + geometry-only 3MF, Quick Start and concise instructions.

Get the free Standard starter
Complete · Cults

Modular Armour Attachment System

All 71 printable variants: joiners, locking bases and hoods, magnetic bases, magnetic and non-magnetic straps, and stitch mounting hardware.

71 STL + 71 matching 3MF files. START HERE and accurate inventory accompany the dated release.

CA$7.99Introductory price · digital files

Get the complete system

Personal / non-commercial use under each listing's license. Checkout and download are handled by MakerWorld or Cults.

Coming soon

Ready-made kits — coming soon.

For now, this launch is for digital files you print yourself. Physical kits are not available to order yet.

FAQ

A few things before you print.

Do Standard and Mini straps fit each other's bases?

No. Match Standard TPU straps with Standard bases, and Mini straps with Mini bases. The families share the PLA mounting post/ring interface and the 8 × 2 mm magnet size.

What is in the free starter?

Four Standard designs: the S1 one-mount base, Flat Standard 60 mm strap, Standard Round post and F/Firm ring. Each comes as STL and 3MF, with the Quick Start and concise instructions. Print two bases, one strap, two posts and two rings; add eight magnets.

How do I set up the magnetic print pause?

Set the pause in your slicer. Find the first toolpath that closes each magnet cavity and verify a pause before it starts, while the pockets remain open. Check the exact part, orientation, scale and layer settings in Preview, then check magnet polarity before resuming.

Has every variant been worn in the torso?

The initial wear trial used four straps in my own torso build. The newer interior photo shows the current layout with additional lower straps. Joiner photographs show open and capped assemblies, without establishing that each shape has been installed or worn. The four long straps keep their EXPERIMENTAL filename label.

Do I need a PLA pen?

No. Leave the ring snap-only for a serviceable mount. Attach the bare footprint to your shell with a suitable adhesive or PLA pen stitching, then let it cool before adding TPU. Optional fusion uses fresh PLA in the seated ring's top cup/channel; keep the TPU seat, split and end lands clear, let it cool, and treat that post/ring joint as permanent. The magnetic strap can still be released from its base.

How do I take the strap off?

Support the base, then lift or peel the plug near its neck. Release the connector locally rather than pulling on the middle of the strap. The permanently fused mounting joint, if used, stays in place.

Can every mounting footprint sit next to every other one?

Check pad clearance in your layout. For the close three-mount Standard S3 base, use Standard Round, Compact Round or Compact Square. Large Square and Rounded Triangle need more space; dry-fit neighbouring pads.

Can I buy printed parts or sell my own prints?

Ready-made kits are coming soon; this page does not take physical orders. The digital launch is personal/non-commercial. Check the listing's license; it does not grant commercial resale rights.

Safety

Cosplay attachments. Use with care.

Keep loose magnets away from children and pets. Swallowed magnets can cause severe injury. Stop using a damaged part if a magnet becomes exposed or loose.

These parts have no load rating and are not for body-weight support or protective equipment. Allow PLA pen joints to cool fully before touching or adding TPU.

Follow your printer and pen instructions. See the CPSC magnet safety guidance.