STEP/CAD Import Overview
LOP supports importing 3D CAD files in the STEP format, allowing you to represent physically complex items — such as industrial machinery, automotive components, custom-fabricated parts, and irregularly shaped products — with full geometric accuracy in your load plans.
Instead of approximating an oddly shaped part as a simple cuboid, you can upload its actual 3D model. LOP processes the file, extracts precise dimensions, calculates the true volumetric envelope, and generates a lightweight 3D preview that renders directly in the load planning editor.
Why Use STEP Import?
Standard box-shaped items are straightforward to define: enter length, width, and height and you're done. But many real-world cargo items are not boxes. A turbine housing, a car bumper, a custom-molded plastic assembly — these have irregular profiles that simple rectangular estimates will either over-pack (wasting space) or under-pack (misrepresenting how much room the item actually needs).
STEP import solves this by working from the item's actual geometry:
- Accurate bounding box — LOP computes the true axis-aligned bounding box from the 3D model, not a manual estimate
- Precise volume calculation — volumetric fill rates in your load plans reflect real item volume, not rectangular approximations
- 3D preview in the editor — the actual shape is rendered in the loading scene so planners can visually verify placement
- Center of mass — LOP calculates the geometric center of mass from the model, improving weight balance calculations
Typical Use Cases
STEP import is most valuable when you are loading:
| Industry | Examples |
|---|---|
| Automotive | Engine blocks, bumpers, door panels, wheel assemblies |
| Industrial machinery | Compressors, pump housings, gearboxes, bracket assemblies |
| Aerospace | Structural components, nacelles, interior modules |
| Consumer electronics | Custom enclosures, display assemblies, battery packs |
| Custom manufacturing | One-off fabricated parts, tooling, molds, fixtures |
If your cargo is mostly standard pallets, cartons, or drums, STEP import is not necessary — the standard item creation form is faster. STEP import is most useful when shape complexity genuinely affects how tightly items can be packed.
How the Process Works
When you upload a STEP file, LOP runs it through a cloud processing pipeline:
- Upload — the file transfers to LOP's cloud processing service
- Parsing — the STEP geometry kernel reads the B-rep (boundary representation) data
- Analysis — the bounding box, total volume, and center of mass are computed
- Tessellation — the smooth CAD surfaces are converted to a polygon mesh for real-time rendering
- GLB export — the mesh is packaged into a compact GLB file for the 3D viewer
- Completion — the item record is updated with all computed properties
Processing typically takes between 10 seconds and 5 minutes depending on the geometric complexity of the model. Simple single-part files finish in under a minute. Large assemblies with hundreds of sub-components take longer. An elapsed time counter is shown during processing, and a reassurance message appears after 60 seconds to let you know the job is still running.
You do not need to wait on the page while processing runs. LOP updates the item automatically when processing completes — a "STEP processing complete" badge appears on the item card. You will see the 3D preview the next time you open the item.
Manual Orientation
After a STEP file is processed, you can adjust the item's orientation directly in the Item Library using the manual orientation tools. This is critical for items whose CAD orientation does not match how they should be placed in a container.
The orientation you set in the library is saved permanently and used whenever the item is added to a plan. You can further adjust orientation in the viewport editor using the Rotation Display panel (90° increments), which is a separate rotation layer.
For full orientation workflow details — including Set as Bottom, axis rotation, auto-rotate preview, and reset — see Uploading STEP Files.
Supported Formats
LOP accepts STEP files conforming to ISO 10303 AP203 and AP214 protocols. These are the standard export formats from all major CAD platforms including SolidWorks, Autodesk Fusion 360, CATIA, Siemens NX, and Autodesk Inventor.
IGES (.igs, .iges) and STL (.stl) files are not currently supported.
For a full list of compatible CAD software and export settings, see Supported Formats.
File Size Limit
The maximum file size is 250 MB per upload. Most single-part STEP files are well under 50 MB. If your file exceeds the limit, simplify the model in your CAD tool first — remove internal features, hollow cavities, and detailed surface textures that do not affect the external shape.
Very large STEP files (50 MB+) may take 5–15 minutes to process and consume significant server memory. Files over 100 MB carry a higher risk of timeout. If processing fails, try simplifying the model or exporting the assembly's outer shell only.
Next Steps
- Uploading STEP Files — step-by-step upload instructions
- Processing Stages — what happens to your file in the cloud
- Supported Formats — compatible CAD software and export settings
- FAQ & Troubleshooting — common issues and solutions