DOCUMENTATION
Four Echelon API
Two endpoints. Four Cad turns a CAD file or drawing into structured JSON; Rowe reasons over that structure and returns typed spatial output. Everything else on this site is a surface over those two calls.
The two calls
POST /api/v1/cad/extractFour Cad
Upload STEP, IGES, DXF, PDF, SVG, or draw.io. Get four-cad.extraction.v1 back: entities, dimensions, solids, faces, annotations.
POST /api/v1/responsesRowe 1.0
Send a cad_scene or point_cloud_scene with a task_type. Get typed spatial output, usage, and a request_id back.
Recommended path
What you can send
STEP / STPsupported3D solids, faces, exact volumes
IGES / IGSsupported3D solids and surfaces
DXFsupported2D entities, dimensions, annotations
PDFsupportedVector drawing entities and annotations
SVGsupportedVector drawing entities
draw.io (.drawio / .xml)supportedDiagram nodes with absolute geometry, containers, connectors with direction, spatial relations
OBJ / STL / JSONsupportedPoint clouds and meshes, browser-side
SolidWorks native (.sldprt / .sldasm)
Export to STEP and upload that. The API returns HTTP 415 — deliberately, not as a bug.
Latency SLAs
The status page reports single-probe latency samples. We do not publish p50/p99 guarantees.
Head-to-head accuracy claims
We publish our own eval methodology, every scoring condition, and error bars. We do not claim to be best, superior, or state of the art.
Diagram formats other than draw.io
Visio, Lucidchart, and Mermaid have no parser and no normalized contract today. draw.io (.drawio / .xml) is live; the rest are on the roadmap, not shipped.