Decimify: Free SketchUp Polygon Reducer & Mesh Optimizer

Decimify is a free SketchUp polygon reducer that imports external models in GLB/STL format and reduces the face count of SketchUp geometry. SketchUp 2020 added native GLTF/GLB import — but it has no built-in decimator. When the imported object has a dense mesh, SketchUp’s Soften/Smooth Edges and Hidden Geometry only change how faces are displayed, not how many actually exist. The face count, and the slowdown, stay. Decimify reduces the actual polygon count in place, right inside SketchUp.

Video

How Decimify Reduces Polygon Count in SketchUp

Most SketchUp polygon reducers use C++ native extensions — fast, but require platform-specific builds and Apple notarization on macOS, which increases development cost and is part of why tools like Skimp cost $229. Decimify’s simplification engine is a Rust module compiled to WebAssembly (WASM), running inside SketchUp’s HtmlDialog (an embedded Chromium browser) on a background thread. No external server — computation happens locally in the dialog. This architecture eliminates the per-platform build cost, which is why a free tier is possible at all.

The preview renders inside the dialog as you drag the slider. When you click Apply, Decimify writes the simplified geometry back to the selected Group or Component. Raw loose geometry must be grouped first — the tool only operates on Groups and Components.

Features

• Groups & Components preserved — multi-level hierarchies survive intact; reused instances stay linked. Reduce one Component instance and every placement in the scene updates.
• Materials & UV Mapping intact — per-face texture projection and multi-material assignments are kept. If UV mapping is broken on the source mesh, see Known Limits below.
• Soft / smooth edges kept — edge shading flags are captured and re-applied, so a decimated curved surface still renders shaded instead of faceted.
• Import GLB / STL — load a file directly, simplify, then commit it as a new Component into the scene.

Settings

Known limits

• Broken UV blocks reduction. When a mesh has malformed UV seams or faces missing UV data, the algorithm refuses to merge faces across those boundaries to avoid texture distortion. The slider appears to do nothing. Fix: turn off Keep UV, reduce, then re-apply texture manually if needed.
• Output is always a triangulated mesh. Coplanar edges are hidden and softened automatically, so flat surfaces look clean in the viewport — but the underlying geometry is triangles. This matters if you later need to edit faces or export with quad topology.
• Very small Components (2–4 faces) cannot simplify further. The algorithm needs enough adjacent faces to merge. Leaf-detail models, screw threads, or fine lattices often have geometry too small to reduce.

Install Decimify SketchUp Plugin

⬇ Download

1. In SketchUp: Extensions → Extension Manager → Install Extension, pick the decimify.rbz file.
2. Restart SketchUp. The Decimify panel appears under the Extensions menu.
3. Sign in with your 3dshouse account by clicking “Sign in with 3dshouse” — it opens a browser login automatically.

Requirements

• SketchUp 2022 or newer.
• Internet connection required.

Typical uses

• Reducing dense furniture or context models downloaded from 3D Warehouse — a common polygon reduction workflow before adding heavy models to a project scene.
• Importing GLB/STL assets from a supplier, simplifying geometry, then placing as a SketchUp Component.
• Quick free pass on any object causing lag — drag the slider to 30% reduction, inspect the result, apply if the silhouette holds.

Free vs Pro

⬆ Upgrade to Pro