Name: BlockBuilder Studio
Author: Marjers

What v0.6 brought

Direct modelling that finally feels like CAD.

Push/Pull on any face including slanted ones. Reference planes, axes, midpoints. Sketch + Revolve. Pattern with skip-list. Live-scrub sliders. Edge-hover dimensions. Maths in every number field. Ten new moves in v0.6 that no browser modeler has.

See every feature →

Real screenshots

This is what it actually looks like.

No mockups, no hand-drawn figures. The real app, real geometry, real exported STLs.

BlockBuilder Studio editing a high-detail Porsche 911 STL import, fully orbital camera, smooth shading, viewport unchanged from a primitive. — Porsche 911 import · ~150k tris · orbited, no lag

Mercedes-Benz SLS, lime-shaded STL import standing on the workplane. — Mercedes-Benz SLS · imported STL

Rhino Beetle Wrestler selected, with the Properties panel showing size, position, opacity, colour swatches, metrics (volume, surface area, tri count), and Lock / Reset / Delete actions. — Properties panel · live volume + surface area

A high-poly Eiffel Tower STL import shown in BlockBuilder with the Properties panel reporting 123k triangles and a volume of 13.43k cm³. — Eiffel Tower · 123k tris · live metrics

Sloth Yoga character STL standing on a base, lime-shaded, viewed from the front. — Sloth Yoga · imported character STL

A modelled hinge with 16 evenly spaced cylindrical holes, made by combining a box with hole cylinders via Group + Bake. — Hinge · solids + holes grouped + baked

Angry Pikachu STL import, coral-shaded, full-body. — Angry Pikachu · imported character STL

Workflow

From idea to printable STL
in four steps.

Five minutes from first launch to a printed bracket. No tutorial required, but eighty-five short ones wait at /tutorials if you want them.

01

Drop in a shape

Drag any of the 13 primitives from the left panel. Live-scrub any slider in Properties to morph the shape in real time. Type 2*12+4 into any field, it evaluates.

02

Combine with CSG

Group (Ctrl+G), Hole (subtract), Intersect (Ctrl+Shift+G). Full Boolean stack, reversible until you Bake.

03

Push/Pull on any face

Click any face, even a 30° slant on a Wedge, drag away. A new prism extrudes along that face's normal. Add chamfers, fillets, hollow shells, arrays with skip-list, all in a few clicks.

04

Export · slice · print

Click STL, OBJ, or STEP AP203. Open in Bambu Studio, Cura, PrusaSlicer, or import into Fusion. Done.

Power tools · v0.6

Not just blocks.
Real CAD moves without the menus.

Six features that put BlockBuilder ahead of Tinkercad's web app. Watch each in <30 seconds at /tutorials.

01

Push / Pull on any face

Click a face, even a slanted one on a Wedge or Pyramid lateral, then drag away. A new prism extrudes along that face's normal. The 30° wall finally gets its tab in one gesture.

02

Reference geometry

Drop a translucent plane through 3 picked points, an axis along any edge, a midpoint marker on any edge. Snap body-drag and resize handles to them. Promote any plane to the active workplane.

03

Sketch + Revolve

Click points to draw a polygon, hit Enter, it extrudes. Or hold the mouse and scribble freehand, the outline closes and extrudes. Or sketch a 2D profile and revolve it 360° for vases, bottles, funnels.

04

Pattern v2 with Skip

Linear or circular arrays, then type 3, 7, 9 into the Skip field and those copies drop out. Hex grids with a missing centre, masonry with feature gaps, all in one step instead of duplicate-and-delete.

05

Edge-hover dimensions

Move the cursor near any feature edge. A label pops up with the edge's exact length. Hidden triangulation diagonals are filtered out, only the edges you can actually see. Plus a Ruler tool for two-point distance.

06

Touch-tuned on mobile

Floating rail UI on tablets (Shapr3D-style), bottom dock on phones (Womp-style), long-press radial for Duplicate / Hide / Group / Delete. Touch handles are 1.6× bigger so fingertips hit them.

Also new in v0.6: Intersect boolean, dimension overlay, math in any number field (2*12+4, sqrt(50)), Chamfer + Fillet on 10 primitives, neighbour-snap on resize handles, shortcut palette (Ctrl+K), STEP AP203 export. Read the full list →

What you get

Six promises. No fine print.

Same commitments for the free version and the licensed one. Same software, same code, same respect.

Fully offline

The app never makes a network request once installed. Plane, air-gapped workstation, café Wi-Fi outage, same behaviour.

No accounts, ever

No sign-up. No email confirmation. No "verify your identity". Install and use. Commercial licences are verified offline against the local file.

No upload limits

Imports happen locally. Bring in a 500 MB STL with 5M triangles, your RAM is the only limit. BVH-accelerated picking handles it.

Your files stay yours

Saves are plain JSON on your disk. STL exports land in Downloads/. Nothing leaves your machine unless you share it.

No tracking

Zero telemetry. Zero analytics. Zero cookies. The app doesn't know you exist after install. This website doesn't either.

No subscription

Personal use is free forever. Commercial licence is €12 once, lifetime, every future update included until v1.0+.

Use cases

Built for the work,
not the workflow.

What people actually make with BlockBuilder.

3D printing

Custom replacement parts

Bracket broke? Cabinet handle missing? Measure with a calliper, model in 5 minutes, print in 30.

Prototyping

Idea to mock in an afternoon

Faster than Fusion for blocky designs. Move to parametric CAD once the proportions feel right.

Education

Classroom 3D without logins

No student accounts to set up, no schoolwide trust forms. Each PC runs its own instance.

Makers

Jigs, fixtures, organisers

Custom boxes, tool holders, drawer dividers, GoPro mounts. The boring practical stuff 3D printing is best at.

Remixers

Edit imported STLs

Pull a model off Printables, scale it, slice a section, drill a hole, re-export. No 25 MB upload cap.

Tabletop

Bases · terrain · props

Hex bases, ruined walls, simple miniatures. Star + polygon + extrude get you 80% of the way.

Support & licence

Free forever.
Three ways to give back.

BlockBuilder Studio is a one-person project. It will always work for free. If it earns its place on your machine, here's how to keep it alive.

Use it free

€ 0 / forever

Hobby, learning, home prints, classroom, no account, no time limit, every feature.

Every feature unlocked
Unlimited STL · OBJ · STEP exports
Free updates forever
Soft reminder every 25 launches

Download free

Buy me a coffee

€ 3+ one-off · any amount

For the personal users who want to chip in. No commercial rights, just a thank-you that keeps the project going.

Pick any amount you like (€3, €5, €10…)
Funds new features and bug fixes
One-time, no subscription, no account
Honest thanks, not licensing

☕ Buy me a coffee

Commercial licence

€ 12 once · lifetime

If you sell prints, freelance, or use it for paid work. Also the highest tier of support.

Commercial-use rights, sell, freelance, agency
Silences the in-app soft reminder
Priority email support · 48h reply
Every machine you own, lifetime updates
Funds the next features, same as coffee, bigger pour

Buy licence, €12

Why ask at all? BlockBuilder Studio is built by one person on evenings and weekends. No VC money, no analytics-funded sale of your data, no upsells. The €12 licence and the coffees are how it stays alive without becoming WinRAR (you know the dialog). Pick whichever feels right for how you use it.

One app, every screen

On your desk.
On your iPad.
On the bus on your phone.

Same project, same tools, same STL out the other end. No account, no cloud sync, no compromises per device.

BlockBuilder Studio on a 1440 px desktop. Toolbar across the top, shape library on the left, 3D canvas centre with a filleted base plate, cylinder, sphere and wedge. Properties panel with sliders on the right.

Desktop · Windows / macOS / Linux

BlockBuilder Studio on iPad. Vertical tool rail on the left, 3D canvas centre with a filleted box, sphere and red cylinder. Properties card on the right with width / height / fillet sliders.

iPad & Android tablets · rail UI

iPhone & Android · dock UI

Open in your browser, on any device → Works offline after the first visit. Add to Home Screen for a real app icon.

Download · v0.6.0-beta1 · ~105 MB

Pick your OS.
One click. Sixty seconds.

No email, no signup, no waitlist. The download starts immediately.

On a phone or tablet? Skip the download, open the app straight in the browser:

Open BlockBuilder in browser →

Tablet + phone-optimised. Works offline after first visit. Add to Home Screen for an app icon.

Windows 10 · 11

BlockBuilderStudio-v0.6.0-beta1-portable.zip 105 MB · Portable · Unzip and run

macOS 12+

Coming soon Universal · Intel + Apple Silicon

Linux x64

Coming soon AppImage · No install

v0.6.0 · Released June 2026 · Source on GitHub · Changelog →

Windows SmartScreen may show a warning on first launch (binary not yet code-signed). Click More info → Run anyway. Why?

Windows 10 / 11 · x64 · 4 GB RAM · WebGL2 (most onboard graphics from 2015+)

macOS 12 Monterey or later · Intel x64 or Apple Silicon (M1+)

Linux Ubuntu 22.04+ / Fedora 38+ / Arch / any distro with FUSE

After the download, three steps

1

Extract the .zip

Right-click BlockBuilderStudio-v0.6.0-beta1-portable.zip → Extract All… (or use 7-Zip). Pick any folder, Desktop, Documents, anywhere with write access.

2

Run BlockBuilder Studio.exe

Open the extracted BlockBuilderStudio folder. Double-click BlockBuilder Studio.exe. On first launch Windows SmartScreen may say "Windows protected your PC", click More info → Run anyway.

3

That's it, start modeling

No installer. Nothing in Program Files, no registry keys, no shortcuts unless you make one. To uninstall: delete the folder. To update: download the next release and replace it.

Want a desktop shortcut? Right-click BlockBuilder Studio.exe → Send to → Desktop (create shortcut).

FAQ

Questions, answered honestly.

If something here is unclear, email geral@marjers.com, replies usually within 48 hours.

Is it really free?

Yes. Free for personal use, no time limit, no feature lockout, no nag screens you can't dismiss. The €12 commercial licence is for people who use exports in for-profit work (selling prints, freelance, classroom) and silences the occasional reminder dialog. Everyone else can use it forever for €0.

Do I need an account or internet connection?

Neither. Once installed, the app never makes a network request. Your work stays on your machine. No telemetry, no analytics, no auto-uploads.

Where is my work saved?

Two places. Autosave: localStorage in the app's profile folder, restored on next launch. Project files: standard .json on disk that you save explicitly. STL/OBJ exports go wherever your downloads land (usually Downloads/).

Why does Windows show a SmartScreen warning?

Because the binary is new and SmartScreen hasn't built reputation for it yet. Click "More info" → "Run anyway" and it goes away forever for that install. Once enough people install BlockBuilder, the warning disappears for everyone. Builds are code-signed; the binary is genuinely from Marjers and contains no malware. You can verify the signature in the .exe properties.

Can I use it commercially?

Yes, with a one-time €12 commercial licence, buy here. Covers selling prints, freelance work, paid classroom use, agency work, anything for-profit. Personal/hobby use stays free.

Is this CAD?

Not in the engineering sense. BlockBuilder is a direct modelling tool: drag primitives, scale them, combine with booleans. No parametric history, no constraints, no assemblies, no engineering drawings. It's optimised for the 80% of 3D-printing work that doesn't need those features, brackets, organisers, replacement parts, props, jigs. For mechanical engineering with version-controlled geometry, use a parametric CAD package.

Can I import existing STL or OBJ files?

Yes. Drag any .stl or .obj into the viewport (or use the Import button). Imported meshes behave like primitives: move, scale, rotate, colour, mark as Hole, group with others, run CSG against them. Big meshes (100k+ triangles) get an automatic BVH for fast picking.

Can I export to STEP?

Yes, with a caveat. BlockBuilder works internally with triangle meshes, not parametric CAD surfaces. The STEP export wraps the mesh in an AP203 faceted B-Rep file that Fusion 360, SolidWorks, FreeCAD, Onshape and most CAD/CAM tools will open as a mesh body. You won't get editable parametric features. For passing geometry to a CNC shop that requires STEP, this is a working option.

What if my STL fails the boolean operation?

Imported meshes need to be watertight (manifold) for CSG. Use the Repair button in the Properties panel: it welds duplicate vertices, drops zero-area triangles, and rebuilds normals. Resolves most failures.

Is the source code available?

Not yet. Open-sourcing is on the roadmap once the code is more polished. The Electron + Three.js stack is well-known with no proprietary dependencies, so the timeline is mostly about cleaning up.

How do I get help or report bugs?

Email geral@marjers.com with a description and, if possible, the saved .json that triggers the bug. Replies usually within 48 hours.

Touchscreens, iPads, phones?

Fully supported in v0.6. Tablets get a floating left rail (Shapr3D-style) with the primary tools plus a Properties card that slides in on the right. Phones get a six-icon bottom dock (Insert / Undo / Group / Edit / Help / More), bottom-sheet Properties, and a long-press radial menu for Duplicate / Hide / Group / Delete. Two-finger orbit + pan and pinch-zoom work natively. Touch handles are sized 1.6× on coarse pointer so fingertips can hit them.

Try it now at blockbuilder-app.pages.dev from any device. Paid apps for App Store and Play Store ship after v0.6 leaves beta.

Get notified about new releases

One short email when there's a new version, with what changed. No marketing, no second email. Unsubscribe with one click.

Model in minutes. Print the same day.

Direct modelling that finally feels like CAD.

This is what it actually looks like.