LOCAL MODEL VIEWER

View STEP or STP CAD Files

Inspect CAD geometry in a local, tessellated 3D preview. See model dimensions, source units and mesh parts without uploading your file.

STEP and STP Viewer OnlineIDLE

No model loaded

Your geometry will appear here.

3D VIEWPORT

Supported preview

Self-contained STEP / STP B-rep files with supported explicit length units, solid bodies, shells and assembly placements..

The preview is a tessellation of the CAD model

OCCT turns supported CAD faces into triangles for the browser viewport. Draft is useful for an initial inspection; finer settings add triangles around curves. Bounds and mesh-part counts come from this tessellation. They are not exact analytic measurements or an editable reconstruction of the assembly tree.

How to use this viewer

Choose a STEP or STP file. The CAD engine loads only when needed.
Select Draft, Balanced or Fine and apply a quality change to rebuild the preview.
Orbit, pan, zoom and inspect the source unit, mesh-part count and dimensions.

Limitations to check

The preview is a triangle approximation of CAD surfaces. Bounds are measured from that tessellation, not exact analytic surfaces.
Parts and shells are shown in their assembled positions; the original assembly tree is not editable. Colors and design metadata are omitted.
External references, mixed or missing length units, wire-only geometry, CSG and tessellated-only STEP constructs are rejected. This viewer does not validate manufacturing quality.

File and processing limits

STEP/STP up to 10 MiB, 100,000 entities and 10,000 source faces.
Up to 500,000 vertices, 250,000 triangles and 128 mesh parts/shells; binary STL output up to 64 MiB.
45 seconds per job. CAD WebAssembly memory is capped at 256 MiB; JavaScript and rendering use additional memory.

Processing happens in this browser; your file and filename are not uploaded. Cancel, reset or replace the file to stop its worker. Downloads are generated locally.

Questions about this workflow

Why does the first STEP file take longer to open?

The local CAD runtime loads when needed, then tessellates the selected model. Larger models and finer tolerances take more processing time and memory; a bounded job can be cancelled or time out.

CAD import uses OCCT / occt-import-js. Open-source notices and library source.