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Online CAD File Viewing Tools

Online STEP, STP & DWG Viewer

Open STEP, STP and supported DWG/DXF files online without installing CAD software. Inspect 3D models, preview 2D drawings in real time, and export the current DWG or DXF view to PDF.

STEP 3DSTP 3DDWG 2DDXF compatible

Your selected CAD file is processed locally in this browser and is not uploaded to MSTFAB.

No file open

Drop a STEP file here

Or select a standard .step file from your device.

STEP · Maximum 100 MB · Your file stays on this device

Loading viewer…
FileNo model loaded
File size–
Model size–
Parts–
Triangles–
Rotate: left drag or one-finger dragPan: right drag or two-finger dragZoom: wheel or pinch
Three selectable viewers, one page

Choose STEP Viewer, STP Viewer or DWG Viewer. DXF is also accepted in the 2D workspace.

Private browser processing

The selected file is read by code running on your device. This tool does not upload the drawing or model to MSTFAB.

Practical PDF export

Export the current DWG/DXF view to a PDF for quick sharing. Use native CAD plotting when vector fidelity and formal drawing control are required.

The quick answer

The MSTFAB online STEP, STP and DWG viewer opens common OEM CAD files without desktop CAD software or an account. MSTFAB is the trading name of Guangzhou Maisituo Sheet Metal Manufacturing Co., Ltd. Choose one of three clear modes: STEP Viewer for .step models, STP Viewer for .stp models, or DWG Viewer for supported .dwg and .dxf drawings. The 2D workspace shows a real-time browser preview and can export the current visible view to PDF. Files are processed locally and are not sent to MSTFAB.

File privacy and data handling

When you select a STEP, STP, DWG or compatible DXF file, the viewer reads it in the current browser session. The selected CAD file is not uploaded to an MSTFAB server and the viewer does not create an account, project folder or cloud copy.

Viewer processing
Runs locally in the current browser session.
MSTFAB server copy
None is created by the viewer.
Cloud project history
Not provided. Close or refresh the page to end the session.
RFQ file transfer
Occurs only when you separately choose and submit files through an inquiry form.

Local browser processing avoids an unnecessary server copy. Your device security, browser extensions and company IT policies remain under your control.

MSTFAB engineers reviewing CAD geometry, controlled drawings and empty sheet metal enclosure parts
MSTFAB reviews manufacturing files only after an OEM deliberately submits a released RFQ package.

Choose the viewer that matches the file

STEP and STP use the same 3D geometry engine. DWG and compatible DXF files open in the 2D workspace for pan, zoom, fit and current-view PDF export.

STEP Viewer.stepInteractive 3D preview with rotate, pan, zoom, edge display and standard views.
STP Viewer.stpThe same neutral STEP geometry workflow for files using the shorter extension.
DWG Viewer.dwg / .dxfInteractive 2D preview with pan, zoom, fit and PDF export of the visible view.
  1. Select STEP, STP or DWG Viewer.
  2. Choose or drop the matching file from your device.
  3. Inspect the geometry. Export the visible DWG/DXF view to PDF when useful.

Use the preview for geometry, not as a manufacturing release

The viewer answers a quick visual question. A production quotation still needs controlled files and the information that defines what the factory must build and inspect.

Useful before an RFQ

  • Confirm that a supported CAD file opens.
  • Check visible shape, orientation and obvious interfaces.
  • Rotate a 3D model or pan and zoom a 2D drawing.
  • Create a PDF of the current DWG/DXF browser view.

Still needed for production

  • Part number, released revision and controlled PDF drawing.
  • Material, thickness, finish, quantity and hardware.
  • Tolerances, critical dimensions, weld notes and inspection requirements.
  • Native CAD review when fonts, Xrefs, layouts or proprietary objects are critical.
DWG-to-PDF output and plotting limits

The PDF button captures the current visible browser view at high resolution. It is useful for quick review and sharing, but it is not a CAD-grade vector plot or a released engineering drawing.

DWG/DXF compatibility and open-source components
  • Custom and proxy objects may not display like the authoring application.
  • External Xrefs, raster images and SHX fonts must be embedded or supplied separately.
  • Large drawings need more browser memory and normally work better on desktop.

The 2D preview uses @flyfish-dev/cad-viewer and LibreDWG WebAssembly under the AGPL-3.0 license.

Files MSTFAB needs for a sheet metal quotation

Send a released STEP or STP model plus a matching dimensioned PDF whenever possible. Add revision, material, thickness, finish, quantity, hardware, weld notes, critical dimensions and inspection requirements.

Read the CAD RFQ file guide.

Common questions

Short answers about browser compatibility, privacy and the boundary between a visual preview and a controlled manufacturing package.

Can I open a DWG file online without AutoCAD?

Yes. Select DWG Viewer and choose a supported .dwg file. The browser generates an interactive 2D preview without requiring a desktop CAD installation.

Can I convert a DWG file to PDF online?

Yes. After the drawing loads, select Export PDF to capture the current visible browser view. The result is for quick review, not a substitute for a controlled vector plot.

Are CAD files uploaded to MSTFAB by this viewer?

No. The selected file is parsed locally in the current browser session. It is transmitted only if you separately choose to submit it through an RFQ form.

Does the DWG viewer also open DXF files?

Yes. The DWG Viewer also accepts supported .dxf drawings in the same 2D workspace.

What is the difference between STEP and STP?

STEP and STP are common file extensions for the same neutral STEP CAD exchange format. The two selectors use the same 3D geometry engine.

Can MSTFAB quote directly from the online preview?

The preview supports an initial geometry check. A reliable fabrication quotation still needs released CAD, a controlled PDF, material, thickness, finish, quantity, tolerances and inspection requirements. Review the CAD-to-production workflow, confirm the expected dimensional inspection records, or send a controlled RFQ package.

Preparing files for a sheet metal quotation

Send the released 3D model, matching dimensioned PDF and manufacturing requirements. MSTFAB fabricates drawing-based sheet metal parts and empty enclosure shells.

The viewer remains local. RFQ upload is a separate action that sends only the files you deliberately select.
Send RFQ Files

Send Drawings for Quote

Attach one file, up to 10 MB (STEP/STP, DXF/DWG, PDF, ZIP, or an image). Include material, quantity, and finish details for an accurate quote.

Quick Quote Request