v0.37.3·Beta·MIT·Windows and macOS

Heavy models. Made light.

The free mesh editor that runs in your browser, built for big CAD assemblies. Everything stays on your computer.

Download GitHub

Fewer triangles, the same shape. It runs in your browser.

MIT licence. No account, no subscription.

A thousand parts and millions of triangles.

I was optimising big CAD models by hand and got tired of it, so I built the tool I wanted, and I kept building, so it now has tons of features. It converts STEP on your computer, finds repeated parts, hidden screws and tiny details for you, and exports one small GLB. Free, open source, nothing uploaded.

The STEP converter is built on OpenCascade and meshes a big assembly on several cores at once. Models are drawn with three.js and simplified with meshoptimizer. The app itself runs in your browser, with nothing to sign in to. It is all local. I made it as user friendly as I could. Started for fun, as a UX exercise, but it is a serious tool.

Convert

STEP in. Light GLB out.

Names, colours and the part tree come through.

Clean

Finds the hidden. Gone in one click.

Bolts, tiny parts and holes.

Shrink

320 MB to 11 MB. Half the triangles.

One press of Smart optimise.

Trust

Every step undoes. Nothing uploaded.

Runs on your computer. Free.

Claude

Just tell Claude. It runs the tools.

Say what it is for. Claude does the job.

A truck front axle, light enough to pull apart live as you scroll

So light, it comes apart live.

33 MB of CAD, now 1.3 MB. All 295 parts move as you scroll.

TrianglesBefore540,007After250,075

File sizeSTEP33.4 MBGLB11.4 MBWeb GLB1.3 MB

54% fewer triangles, GLB 9× smaller.

Mercedes-Benz Arocs 8×8 axle. Not affiliated.

MeshOptimiser: Quick wand: a ring of commands under the cursor. Here, Remove empty parts. — 01Quick wandA ring of commands under the cursor. Here, Remove empty parts.

MeshOptimiser: Delete small parts: 102 parts under 2% of the model’s size, highlighted before they go. — 02Delete small parts102 parts under 2% of the model’s size, highlighted before they go.

MeshOptimiser: Heatmap: parts coloured by triangle count. — 03HeatmapParts coloured by triangle count.

MeshOptimiser: Fasteners: 376 found by shape, 354,399 triangles, 9.6% of the scene. — 04Fasteners376 found by shape, 354,399 triangles, 9.6% of the scene.

MeshOptimiser: Exploded view: the axle pulled apart to 165%, with four parts picked out. — 05Exploded viewThe axle pulled apart to 165%, with four parts picked out.

The truck axle in these pictures is a Mercedes-Benz Arocs 8×8 front axle. Trademarks belong to their owners; not affiliated.

Why MeshOptimiser

Heavy CAD in. A fast page out.

Made for CAD
STEP comes in with its names, colours and the whole part tree. Nothing is flattened.
Finds by shape
Repeats, hidden screws and tiny parts are found by what they are, not by what the file called them.
Nothing is final
Every step previews first and has an undo, so you can try anything.
Stays with you
It runs on your computer and nothing is uploaded. Free and open source.

Clean-up tools

Advanced STEP clean-up tools, free in your browser.

All features

01Remove holesv15Bolt holes, slots, pockets and lettering: closed, with their walls. Nothing else changes.Read more about Remove holes

02Select hidden partsv2Every screw sealed inside a housing, found and gone in one step.Read more about Select hidden parts

03Fastenersv6Every bolt, screw, nut and washer, found by shape. Whatever the CAD file called them.Read more about Fasteners

04Smart fitv3Two heavy parts: 72,666 triangles down to 212. Same size, same place, same outline.Read more about Smart fit

05Splitv6One fused lump becomes the separate solids it always was.Read more about Split

06Smart optimisev1Every clean-up above, in one press. 646,064 triangles down to 322,988, and one undo puts it all back.Read more about Smart optimise

07Remove floating piecesv2Plugs, shavings and stray dots, gone. The main body always stays.Read more about Remove floating pieces

08Remove hidden facesv1Deletes faces that never show: inside a housing, where two parts meet.Read more about Remove hidden faces

09Triangulationv3Flat faces rebuilt with the fewest triangles. The shape doesn’t move.Read more about Triangulation

10Delete small partsv1Screws and clips too small to see, gone. A slider and a preview show what goes.Read more about Delete small parts

11Repair meshv2Doubled points, empty triangles and flipped faces, fixed.Read more about Repair mesh

12Stacked copiesv1Parts drawn twice in the same place, found and removed.Read more about Stacked copies

13Remove filletsSmall rounds and chamfers taken off a STEP part. The faces on either side are extended until they meet, and the sharp edge is back.Read more about Remove fillets

14Remove thicknessA thin wall becomes the one surface it stands for: a pipe keeps its outside, a bent sheet keeps one face.Read more about Remove thickness

15Remove lettering and logosRaised or engraved text and logos, however the CAD program made them, gone. The surface underneath stays as it was.Read more about Remove lettering and logos

16Fill solid roundA gear, a fan with fins or a clutch with cooling ribs, made one solid round shape that fills its whole outline. A good stand-in seen from a distance.Read more about Fill solid round

Try it

Search is how you get around.

The app’s own search. Type a part, a library item, a command or a sum.

search everythingParts, library items, commands and settings, all from one box.
calculate and convertType a sum or a length. 12*25.4 is 304.8, and 2 in is 50.8 mm.
toggle right thereSwitch things on and off in the results, without opening a menu.
learn the keysEvery command shows its shortcut, so you pick them up as you search.

Quick decimate

Press B. Slide. Let go.

A column of levels opens under the pointer, and the part changes as you move down it. This bracket goes from 1,802 triangles to 900 at 50%.

Try it

The commands come to you.

The app’s own Quick wand. Point at a slice, click a command. Select a part and the ring changes to fit it.

PointA slice lights up. A group fans its commands out.
ClickRuns the command. Click a part first to work on it.
Hold WThe ring comes to the pointer. Let go on a slice to run it.
EscBack to the middle. Runs nothing.

Claude·New

Ask Claude. It does the clean-up.

Describe the job. Claude does the clean-up with the same tools you click, asks before it changes anything, and every change is one undo.

See how it works

Find all the bolts and hide them.
Get this under 5 MB for the web.
Show me before and after.

Latest release

v0.37.3

Full changelog

Save writes over the file, the window’s title follows the scene, MeshOptimiser can be chosen in Explorer’s Open with list, and a long job tells you when it ends. An FBX keeps the names of its materials.

NewSave (Ctrl+S) writes over the file without asking; Save scene as is Ctrl+Shift+S. The window’s title is the scene’s name, with a diamond while changes are not saved.
NewMeshOptimiser can be chosen in Explorer’s Open with list for the model files it reads (the installer adds it); OBJ, FBX, STL, 3MF, USD and Collada can be handed to the program too.
NewSettings › General › Notifications: a notification when a long job ends in the background, and the percent of a running job in the window’s title.
FixMaterial names of an FBX (and other files) were lost; they now come in. Objects with objects under them (Cinema 4D) open as groups, and the pivots set in the file are on the parts.

Pick how you run it.

In your browser

MeshOptimiser Web

Try the app in a tab. Nothing to install.

Launch What is it

On your machine

MeshOptimiser

The full app. Windows and macOS.

Download v0.37.3 What is new

Free

Browser tab

Your computer

Files stay local

STEP to GLB