This STL simplifier reduces triangle count using real edge-collapse geometry processing inside a browser worker. Choose a keep percentage or target count, compare the resulting surface and bounding dimensions, then export a binary mesh. Reduction is lossy: the tool protects a limited bounds tolerance, but you still need to inspect details and manufacturing-critical features.
A decorative model may contain many tiny triangles across nearly flat regions. An STL simplifier can make that mesh lighter to handle while keeping a similar overall shape.
To reduce STL file size, first distinguish text overhead from geometric complexity. Binary encoding can save storage without removing facets. An STL downsizer that removes triangles changes the surface itself, which is a different tradeoff. If all you need is a smaller physical part, use dimensional scaling instead.
Open an ASCII or binary STL and read Before triangles and Before bounds. Confirm the expected dimensions, because fewer triangles should not be confused with deliberately resizing the part. One coordinate unit is interpreted as one millimeter.
Keep percentage and Target triangles describe the same request. For example, retaining 50 percent of a 10,000-triangle model requests 5,000 triangles. Select Simplify mesh and wait for processing to finish. Every run starts from the original import, so trying a second target does not compound an earlier reduction's losses.
The STL simplifier reports the actual after count and bounds. Switch between Preview original mesh and Preview reduced mesh to examine silhouettes, holes and thin details. A partial reduction is labeled when topology or the error limit prevents the requested count. Download the result only after review, then reopen it in your destination application.
The STL simplifier uses meshoptimizer's MIT-licensed WebAssembly simplifier. Identical coordinates are welded into indexed vertices before quadric-error edge collapses select a smaller triangle set. The normal error budget is one percent of mesh extent, an approximate geometric error measure rather than a guarantee for every individual feature.
Each minimum and maximum bounding coordinate must stay within two percent of the longest original dimension, plus a tiny numeric allowance. A result outside that limit is rejected. For a 100 mm longest extent, a bound may shift by up to 2 mm; that tolerance can still be unacceptable for a tight fit.
Topology restrictions can stop the STL simplifier above the target. A two-triangle allowance is used when reporting target success because collapses often remove triangle pairs. The STL simplifier never claims an unreached target was achieved.
You can simplify STL surfaces here, but cannot recover CAD curves, repair holes or guarantee watertight output. Tiny embossed text, narrow walls and sharp mounting details may degrade even when the outer box looks unchanged. Compare the reduced file in your slicer and avoid relying on the preview alone for dimensional approval.
The STL simplifier accepts one file up to 25 MiB and 400,000 triangles. Targets must be whole numbers from four to one below the original count. WebAssembly, JavaScript and Web Workers are required; WebGL supports the preview. You can simplify an STL model online without installation or payment. Stay within those limits and save the download before leaving.
Yes. It collapses edges and exports fewer triangle records, rather than only hiding wireframe lines or compressing a download. The after count describes the real output, and the saved mesh can be reimported independently.
The algorithm respects topology restrictions and an approximate error budget. Some meshes cannot reach the requested count under those constraints. A partial result is labeled with its actual count; try a less aggressive target or another source mesh.
No. It limits changes to the outer axis bounds relative to the longest extent. It does not constrain every local diameter, wall thickness or mounting surface. Inspect features and use a suitable engineering workflow when fit matters.
No. A reduced surface is not a repaired or certified solid. Existing holes, intersections and disconnected components may remain, and lossy changes require fresh inspection before slicing or manufacturing.
Yes. Every reduction uses the original model currently imported into this workspace.
The download is ordinary binary STL with recalculated normals and the reduced triangle geometry. It has no colors, materials or unit metadata. Keep the original and verify the exported dimensions.