Module read 

From parsed exchange structure to a living model.

The reader walks every MANIFOLD_SOLID_BREP (BREP_WITH_VOIDS is one, by subtype) and every SHELL_BASED_SURFACE_MODEL, and rebuilds them bottom-up: points, placements, curves and surfaces into geometry; vertices, edges, loops, faces and shells into topology, shared exactly as the file shares them: a vertex referenced by eight edges is one vertex here too, which is what lets a closed shell close. Edge ranges are re-derived on this kernel’s own parameterizations from the vertex geometry, because STEP’s parameterizations are its own business and carrying them over blind is how off-by-a-period bugs are born.

What the reader does not understand it counts: every instance never visited lands in the report’s skipped table by keyword, and every compromise (a face without a pcurve, a shell that does not close) is a warning with the instance number in it. An import that succeeded with three warnings is a different thing from one that succeeded, and the report is what keeps the difference visible.

Structs

StepImport

A read exchange file: the model, the bodies found, and the report.

StepReport

What an import brought in, and what it left behind.

UntrimmedFace

A face the reader could not trim, with the shape to act on.

WarningSummary

One kind of imperfect import, counted rather than repeated.

Functions

read_step

Read a STEP exchange file’s B-rep content.