RegoSplit - 3D Print Part Optimizer

Tall models don't fit. Multicolor models need a printer you may not own. Overhangs eat filament in supports you then have to cut off.

RegoSplit is one add-on for all three. It cuts a model into flat, low parts that fit back together with pins, dowels or magnets, turns every color region into a solid inlay you can print one at a time on any printer, and shows you the overhangs while you are still sculpting, so you design them out instead of patching them in the slicer.

No manual needed. The top of the panel is a numbered list with one button per step: set up the file, check the mesh, check overhangs, split the colors, cut it down, choose pins or magnets, print. Every option panel below it is named after the step it belongs to, and RegoSplit is in the right-click menu too.

• Magnets. A third way to join parts: matching round pockets on both faces for disc magnets, from 3 x 2 to 10 x 3 mm or your own size. The model comes apart for painting or transport and snaps back.
• Your fit, saved. Press the Coupon socket that took the pin snugly and save it as a profile, such as "A1 PLA". One click sets that clearance again, in any file.
• An assembly plan with every export: every file, how many times to print it, how many magnets to buy, and which cut number joins which parts.
• Better dowels. They still print lying down, now with a narrow flat so they do not roll and chamfered ends so they start into the socket. Cone dowels are now double cones that fit both sockets.
• Tested on Blender 4.2 LTS, 4.5 LTS and 5.2 LTS.
• Fixes for colors read as grey on Blender 5, Edit mode, re-runs that are refused, Back to Draft, exports from unsaved files, and the Overhang Preview on rotated or scaled objects. The full list is in the version notes.

Free cut planes you move, rotate and scale like any object, or one-click Slice by Height. The rectangle is the blade: shrink a plane over one leg and it parts that leg while the other stays whole; cut a neck without touching the hair hanging beside it; open one arm of a pose and assemble the model in stages. A plane bigger than the model cuts straight through, as you would expect. If a rectangle enters a section without coming out the far side, Split stops and tells you the size to use, instead of tearing the mesh.

Three ways to join the parts. Dowel mode drills sockets on both faces and gives you separate dowels, so every part lies flat on the bed with no supports on the joints. Fused mode is the classic pin-on-one-side style. Magnets mode cuts a pocket for a disc magnet on both faces. Cylinder, cone, square and triangle pins; the last two stop parts twisting. Cut numbers are engraved on both mating faces, so assembly order is still obvious months later.

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Every color becomes one closed solid inlay with a matching recess in the body. Print each color separately, even on a single-color printer, and press the pieces together. Optional locating pins make gluing easy. One part per color, not one per patch: a ragged color border still gives you the one big piece you were looking at.

A color that wraps right around the model comes out as a closed collar: it prints beautifully and then will not go on, because its opening is narrower than the shape it has to pass over. RegoSplit tests every part against the body for a real straight-line assembly direction, tells you which ones are trapped, and opens them in one click into segments that close around the model.

Remap a full-color model to the palette you actually have (2 to 32 colors). Perceptual (CIELAB), area-weighted, with a saturation boost so small vivid accents survive the reduction. It writes a _reduced copy; your original is untouched.

A viewport-only overlay, matcap-style, that works in Sculpt too: green prints as-is, yellow is near your critical angle, red needs support, magenta floats in mid-air. It never writes to materials, textures or mesh data: toggle it off and it is gone.

Check Mesh names every problem that can stop a boolean: non-manifold edges, holes, loose and zero-area geometry, self-intersections. Quick Fix welds and closes without touching the shape. Rebuild Solid re-voxelises a self-intersecting sculpt into one watertight surface in a single press, keeps your materials, and leaves a hidden backup. It checks its own work too: if the grid was too coarse for a thin wall it says so instead of handing you a torn model.

Every operation that can take minutes tells you first what is wrong with the model, what the tool is about to attempt, how long Blender will look frozen, and whether your file is saved. Set Print Size catches the classic killer: a model still at meter scale, where every millimeter setting would be a thousand times too big. A Split that is refused leaves your last good parts exactly where they were.

Build-volume presets or a custom bed. Check Bed Fit flags over-size parts. Arrange on Bed lays everything out in a grid at Z=0. Export All Parts writes one STL or OBJ per part, always in real millimeters, whatever your scene unit scale is, plus a plain-text assembly plan: every file, how many times to print it, how many magnets to buy, and which cut number joins which parts.

A test bar with sockets at increasing clearance, the value engraved next to each one, and a test pin. Print it once per printer and material, then press the button of the socket that took the pin snugly: that becomes your clearance. Save it as a profile, such as "A1 PLA" or "MK4 PETG", and one click sets it again in any file. About 0.20 mm on a well-tuned machine, 0.35 to 0.50 mm on most.

Honest limits, so nobody buys the wrong thing:

• Needs a closed manifold mesh. There is a repair path and a non-manifold override, but results without it are not guaranteed.
• Cuts are planar: freely positioned and rotated, but not curved.
• Color regions follow the material assigned to faces. Vertex colors and image textures are not read yet.
• Exports STL and OBJ, not 3MF.
• Pin settings are global per split; there is no per-pin editing yet.
• Articulated and print-in-place joints are out of scope.
• Physical fit always depends on your printer and material. That is exactly what the Calibration Coupon is for.

• Blender 4.2 LTS or newer (extension format)
• Test suite run on Blender 4.2.23 LTS, 4.5.14 LTS and 5.2.2 LTS
• Windows, macOS, Linux
• No internet connection required, ever

I am the person behind TastyVoxels. I have been writing code since long before generative tools were mainstream, and everything that makes this add-on work is an engineering decision, not a prompt: the bounded cut plane that parts one leg and leaves the other whole, the socket clearance model, the sweep that asks whether a part can physically come off the body, the thin-wall guard behind every socket. I specify it, I break it, I fix it, I print it.

I did not build it alone, and I would rather say so plainly. I use AI assistance the way I use every other tool in my pipeline: it writes code with me, and it translates my documentation and this page into English, which is not my first language. Italian is where I think and where I write first. What I do not delegate is responsibility: I answer for every line that ships and for how it behaves.

Every behavior is checked against numbers, not vibes. The suite ships inside the add-on so you can run it yourself:

• 210 automated checks on real geometry, each counted once, all passing on Blender 4.2, 4.5 and 5.2
• 18 removal directions swept per part to decide whether it can actually come off the body
• 0 non-manifold, loose or degenerate faces on the generated parts the suite inspects
• Color separation conserves 97 to 100% of the original volume
• Magnet pockets measured against the volume of the magnet they are cut for

RegoSplit ships no AI. No model, no inference, no telemetry, no network access, no data collection. It is deterministic geometry code that runs entirely offline on your machine, and it will keep working with no service behind it.

The imagery on this page is rendered in Blender (Cycles) from the add-on's real output, with layout and typography done in HTML and CSS.

RegoSplit is still a beta, and I am calling it what it is. Everything described on this page is implemented and passes the automated suite, and I have used it on my own models, but no add-on meets the variety of real files and real printers until it is in other people's hands. Panel wording, defaults and some controls may still change before the workflow settles.

What I have verified, so you know where the line is: the suite runs headless on Blender 4.2.23 LTS, 4.5.14 LTS and 5.2.2 LTS and passes on all three. The magnet pockets and the new dowels are measured by the suite but not yet print-tested on every printer, and I have not print-tested every printer and slicer brand either: the clearance fields and the Calibration Coupon exist so you do not have to take my word for the fit.

It arrives as a beta asking for feedback, rather than as a finished product asking for your trust. In exchange I am asking for something concrete: tell me what broke, what confused you, and what you expected to find and did not.

Write to me in the comments on this page, before or after buying. Every report changes what I build next, and every future version is included at no extra cost.

The add-on teaches itself. The panel opens on a numbered list, and each step ticks itself off as you complete it. Every option panel is named after its step, and a fold-out "What each step does" guide explains each one in plain language, so you never have to leave Blender to remember what a button is for.

Every step is written out in full below.

You do not have to work the panel out on your own. This is the entire workflow in text, in the order the panel presents it.

• Set up the file. Sets print scale so 1 Blender unit = 1 mm and fixes viewport clipping, so small parts stay visible.
• Check the mesh can be cut. Counts non-manifold edges, holes, loose and zero-area geometry and self-intersections. Quick Fix or Rebuild Solid repairs what it finds, and a hidden backup of the original can be kept.
• Check overhangs while you model. Overhang Preview colors the surface by slope. It is view-only: nothing is baked into the mesh. Fix the red and magenta areas and the print needs almost no supports.
• Multicolor? Split the colors. Reduce to the palette you actually own, then Separate turns each color region into an inlay that press-fits into a recess in the body. Single-color model: skip to the next step.
• Cut it down to bed size. Slice by Height for even slabs, or add cut planes and move them where you want the seam.
• Split with pins or magnets. Dowel gives a socket on both sides plus a dowel to print; Fused leaves the pin attached to one part; Magnets cuts a pocket on both sides for a disc magnet.
• Check, arrange, export. Checks every part against your bed, arranges them, and exports one STL or OBJ per part, always in millimeters, with the assembly plan beside them.

Fit too loose or too tight? Print the Calibration Coupon once per printer and material, press the socket that took the pin snugly, and save it as a profile. It is the only calibration the add-on needs.

The same seven steps are folded into the add-on itself, under "What each step does".

Edit > Preferences > Get Extensions > the small arrow at the top right > Install from Disk > pick the zip. The panel appears in the 3D Viewport sidebar (press N) under RegoSplit, and in the right-click menu.

Questions, bug reports and feature requests are welcome in the comments on this page. Updates and support are included for good: no support period, no renewal fee. You buy it once and every future version is yours.