Processing Stages
After you upload a STEP file, LOP runs it through a multi-stage cloud processing pipeline. Each stage transforms the raw CAD geometry into the data that powers accurate load planning and 3D visualization.
The Processing Pipeline
Stage 1 — Queued
The file has been received and is waiting for a processing slot. Queue times are typically under 5 seconds during normal usage. During peak hours, files may wait up to 30 seconds before processing begins.
The item in your library shows a "Processing" badge with a spinner while it is in the queue. An elapsed time counter begins ticking to show how long processing has been running.
Stage 2 — Parsing
The STEP geometry kernel reads the file and reconstructs the boundary representation (B-rep) model from the STEP protocol data. This stage handles:
- Reading all STEP entities (shells, faces, edges, vertices)
- Resolving assembly hierarchies if the file contains multiple parts
- Identifying the coordinate system origin
- Validating that the geometry is manifold (watertight) and usable
What can go wrong here: files that are malformed, use an unsupported STEP schema, or contain non-manifold geometry (open surfaces, duplicate faces) will fail at this stage. See FAQ & Troubleshooting for remedies.
Typical duration: 2–20 seconds
Stage 3 — Analyzing
With the geometry successfully parsed, LOP computes the physical properties needed for load planning:
- Axis-aligned bounding box (AABB) — the smallest box that contains the entire model, aligned to the world axes. This becomes the item's length, width, and height.
- True volume — exact volumetric calculation integrating over the solid geometry. Used for accurate fill-rate reporting.
- Geometric center of mass — the centroid of the solid, assuming uniform material density. Used to improve center-of-gravity calculations in weight balance analysis.
The bounding box computed here represents the minimum rectangular envelope of the model in its default orientation. If your item is always placed in a specific orientation on pallets or in containers, make sure the CAD model is oriented that way before export, or adjust the dimensions manually after processing.
Typical duration: 3–30 seconds
Stage 4 — Tessellating
The smooth CAD surfaces (B-rep) are converted into a polygon mesh (tessellation) suitable for real-time 3D rendering. This involves:
- Sampling each curved surface at an appropriate resolution — fine enough to look accurate but coarse enough to render at 60 fps in a browser
- Building the triangle mesh from the sampled points
- Computing vertex normals for smooth shading
- Applying a default material (the item's color from its LOP settings)
The tessellation resolution is automatically adjusted based on the model's scale. A 10 mm precision instrument part gets finer tessellation than a 5-meter machine base.
Typical duration: 5–60 seconds
Stage 5 — Exporting (GLB Generation)
The polygon mesh is packaged into a GLB file — a binary format of glTF (GL Transmission Format), the standard for efficient real-time 3D on the web. The export process:
- Applies Draco mesh compression to minimize file size without visible quality loss
- Embeds material and color information
- Stores the file in LOP's CDN for fast loading in the editor
The resulting GLB file is typically 5–50× smaller than the original STEP file, enabling it to load quickly in the browser even for complex assemblies.
Typical duration: 2–15 seconds
Stage 6 — Complete
Processing has finished successfully. The item record is updated with:
- Computed dimensions (bounding box L × W × H)
- Exact volume
- Center of mass offset
- Link to the GLB file for 3D preview
The "Processing" badge is replaced by a "STEP processing complete" badge and a 3D model thumbnail in the Item Library. When the item is placed in a load plan, its actual shape is rendered in the editor viewport.
Processing Time Reference
| File Type | Complexity | Typical Processing Time |
|---|---|---|
| Single part | Simple (< 50 faces) | 10–30 seconds |
| Single part | Medium (50–500 faces) | 30–90 seconds |
| Single part | Complex (500–5,000 faces) | 1–3 minutes |
| Assembly | Small (< 20 sub-parts) | 1–3 minutes |
| Assembly | Large (20–200 sub-parts) | 3–8 minutes |
| Assembly | Very large (200+ sub-parts) | May time out |
Processing times are estimates and vary with server load. A file that takes 2 minutes during off-peak hours may take 5 minutes at peak times. Large files (50 MB+) may take 5–15 minutes — a reassurance message appears after 60 seconds to confirm the job is still running. If processing appears stuck beyond 15 minutes, it has likely timed out — check the item status and re-upload if needed.
Monitoring Progress
The processing status is visible in two places:
- Item Library card — a badge shows the current stage name and a spinner icon while processing is active
- Item detail view — the 3D Model section shows the current stage and a progress indicator
Both update in real time without needing to refresh the page. If you navigate away and return later, the latest status is shown automatically.
What Happens If Processing Fails
If any stage fails, the item status changes to "Processing Failed" and the stage where the failure occurred is shown. The item itself is not deleted — you can re-upload the file after making corrections.
Common failure reasons and fixes are covered in FAQ & Troubleshooting.