Simplify a 3D Mesh Online

Drop in an OBJ, STL, GLB, glTF, PLY or OFF model and cut its triangle count while keeping the shape that matters. Compare the result against the original in the viewer, then download it. No account is needed to start.

Formats it opens

  • OBJ
  • STL
  • PLY
  • OFF
  • GLB
  • GLTF

Formats it writes

  • OBJ
  • STL
  • PLY
  • OFF
  • GLB

Anything else is refused when you choose it rather than failing halfway through. See every format MeshCrunch supports.

Limits and privacy

  • Accepts models up to 50 MB without an account; signed-in plans accept larger files.
  • Your model is stored privately in your own workspace and deleted after 24 hours unless you sign in.
  • Without an account you get 3 processing credits per rolling 24 hours. Simplifying a file up to 25 mb costs 1 credit; larger files cost more.
  • Previewing, comparing and inspecting a model use no processing credits.

How it works

  1. 1

    Drop in your model

    Choose a file from your machine. It uploads once to your own private workspace and opens on the Simplify tab, with no account and no sign-up wall.

  2. 2

    Pick auto or a target

    Let auto find the smallest mesh that stays close to the original, or set the percentage of triangles to keep or a triangle budget yourself.

  3. 3

    Compare and download

    Switch between original and optimized without the camera moving, read the triangle, vertex and file-size changes, and download the result in the format you chose.

How online mesh simplification works

MeshCrunch reduces a mesh with quadric-error decimation: it repeatedly collapses the edge whose removal moves the surface least. Every collapse lands on a vertex that already exists, so the result is built from points of the original model rather than new guesses about it.

Each part of the model that carries its own material is simplified separately, so a material stays assigned to the triangles it was painted on. The work runs on our servers, not in your browser, so a large model does not freeze the tab, and closing the tab does not lose the result.

Automatic reduction or a target you set

Auto mode does not apply a fixed ratio. It tries progressively smaller candidates, measures how far each one's surface has moved from the original, and keeps the smallest one inside the quality budget you chose: near-lossless (the default), balanced or aggressive. Two models given the same budget can end at very different triangle counts, because they carry different amounts of redundant geometry.

A target is the other way round. You choose the percentage of triangles to keep, or a triangle budget, and you get that size whatever it costs the shape. Use it when a platform hands you a number; use auto when you want the smallest mesh that still looks like the source.

What is preserved

  • The overall silhouette. In auto mode it is measured rather than assumed, against the model's own size.
  • UV coordinates, carried exactly, when the output format can store them.
  • Materials and their textures, which are never resampled or recompressed, when the output format can carry them. GLB carries everything; an OBJ result keeps its UVs but not the image files, because a result is a single file.
  • Vertex colours, when the output format can store them.

What can change

  • Triangle topology. Triangles are merged, so the edge layout of the result differs from the source even where the shape does not.
  • Normals, which are recomputed from the simplified surface. A hard edge defined only by split normals comes back smoothed.
  • Fine geometric detail. Features smaller than the quality budget allows can be removed, which is what a lower triangle count means.
  • Tangents, which are not carried; renderers regenerate them from the UVs and normals, and the job says so.
  • File size, by less than the triangle count when most of the file is textures. Simplification reduces geometry and leaves images alone.

A measured example

  • An AI-generated pug, uploaded as a 92.3 MB OBJ with 1,993,980 triangles, came back from auto mode at 71,136 triangles, which is 3.6% of the original, and 1.4 MB as GLB.
  • A textured flight helmet went from 94,722 triangles to 16,277, a reduction of 82.8%, with all six materials and fifteen textures intact. Its file went from 46.1 MB to 44.0 MB, because 93% of that GLB is texture data.

Frequently asked questions

Do I need an account to simplify a mesh?

No. Dropping a file creates an anonymous workspace with a small daily allowance of processing credits. The model is stored privately so it can be processed, it is never public, and it is deleted automatically unless you sign in to keep it.

How many processing credits does a simplification use?

One credit for a small file, more for a larger one, because a bigger model takes more compute to process. The exact cost is shown on the button before you start, and previewing or inspecting a model costs nothing.

Will my textures and materials survive?

In a GLB, yes: materials, textures, UVs and vertex colours are carried through. OBJ keeps UVs, normals and vertex colours, but a textured model loses its image files, because a result is one file. STL stores geometry only. If you choose to discard appearance on purpose, the job removes it and can then simplify further across what used to be texture seams.

Can it simplify a rigged or animated model?

No. A model with skinning or morph targets is refused rather than processed, because simplification would silently drop the rig and the result would look like success.

What if my model cannot get any smaller?

If nothing could be removed and re-exporting would make the file bigger, you get your original back and the result reports no saving, rather than a larger file presented as an optimized one.

Can I re-run it with different settings?

Yes. The model stays in your workspace, so you can simplify it again, generate a LOD chain or convert it without uploading it a second time.

Related tools

Further reading

Real models, real numbers, and what each setting actually cost.

Simplify a model

Your model is previewed and measured in this browser and simplified on our servers. The file is stored privately in your own workspace, is never public, and is deleted automatically unless you sign in.

Simplify a model