STEP / STP · VIEWER
Open and inspect STEP files online
Explore a mechanical part or assembly without installing a desktop CAD application. 3DXDE opens STEP files in a browser workspace with an assembly tree, a 3D view and geometry inspection.
The view is triangulated for display, while the imported CAD geometry remains available for supported exact measurements and CAD export.
Understand the assembly
Expand the part tree, select geometry and hide or isolate components to see how a model fits together.
Inspect from useful views
Use standard views, perspective or orthographic projection, section planes and a four-view layout.
Check geometric properties
Read selected-object properties or open Measure for supported distances, lengths, areas and radii.
Step-by-step
Select the STEP file and its dependencies
Open the workspace, choose Open files, and select the .step or .stp file. Include any referenced model files in the same selection.
Confirm the main model
Choose the primary file in the import dialog. STEP units are read from the file. Start with medium mesh quality for the displayed geometry.
Fit and navigate
Press F to fit the visible model. Scroll to zoom, drag the middle mouse button to pan, and hold Shift while dragging the middle button to rotate.
Inspect a part, face, edge or vertex
Use the selection filter to choose the required geometry. A single selection shows its available properties in Inspect; use Measure for comparisons between targets.
Review or export
Use sectioning or isolation to understand internal features. Open Convert when you need a different format, and read the information-loss note before downloading.
STEP and STP refer to the same exchange format
The .step and .stp extensions are both used for STEP CAD files. A STEP model may contain solid bodies, surfaces, part names, colors and an assembly structure. What appears in the viewer depends on what the source application actually exported.
A rendered object is not proof that it is a closed solid. Check the selected part’s properties when a usable volume matters; open or invalid geometry may have no available volume.
Display controls do not edit the source geometry
- Hiding, sectioning and exploding an assembly change its presentation. They do not remove geometry from the exported model.
- Display tessellation controls how smooth curves look. CAD measurements use the retained geometry where supported, rather than the visible triangle count.
- Bounding dimensions derived from the display mesh are approximate. The viewer is an inspection and exchange tool, not a feature-based CAD editor.
If a STEP file does not open
Check that all referenced files were selected and that their names are unambiguous. A damaged or unsupported entity can prevent import even when the filename has the right extension.
A desktop 64-bit Chrome or Edge browser is a practical starting point. Memory use depends on model complexity and tessellation, not just file size. Try coarse quality for a complex model; no fixed large-CAD-file capacity is guaranteed.
Your files stay in your browser
3DXDE reads the files you select and processes model geometry locally in your browser. Model files are not uploaded or saved to a cloud file history. No account is required. The browser still downloads the application and its processing resources when needed.
Referenced files must be included in your selected file group. Missing files, ambiguous names and references outside that group are rejected; model references are not fetched from external websites. Refreshing the page clears the loaded model, so keep your original files and any exports you download.
The public website uses Google Analytics for basic page-visit statistics, including browser identifiers and cookies. Model files, filenames, file paths and geometry are excluded from analytics. Forms, model downloads and model interactions are not tracked.
Common questions
Do I need to upload my STEP model?
No. Choose it from your device and 3DXDE processes it in the browser. See the local-processing explanation above for how dependencies and page refreshes are handled.
Can I view STEP assemblies?
Yes, when the imported file contains an assembly structure. Expand the tree to find components, and use hide or isolate to inspect them. A source exported as a single flattened body will not regain its original assembly hierarchy.
Why do circular edges look faceted?
The viewport displays a tessellated representation. A finer mesh setting can improve the appearance at a higher memory and processing cost; it does not turn an approximate mesh file into exact CAD geometry.
Can I edit dimensions or a design history?
3DXDE supports viewing, measurement and format exchange. It does not provide parametric sketch editing or reconstruct the source application’s feature history.