STEP vs IGES for CAD Exchange

STEP and IGES are both neutral CAD exchange formats, but they come from different generations of interoperability and are not equally capable for modern workflows.

IGES in brief

IGES was designed to exchange geometric entities such as curves and surfaces between different CAD systems. It remains useful for some legacy workflows, especially where surface data is the primary concern.

STEP in brief

STEP is based on the ISO 10303 family and can represent richer product-model information. In everyday mechanical CAD exchange, STEP is generally the preferred neutral format for solids and assemblies.

Why STEP is usually the first choice

Modern STEP translators usually preserve solid topology more reliably than an IGES surface quilt. A valid solid is easier to measure, section, mass-check and pass downstream to CAM, DFM or simulation.

When IGES still appears

Legacy machines, older supplier workflows and specialized surface pipelines may still request IGES. If a recipient explicitly needs it, export and validate it rather than assuming STEP is accepted everywhere.

Translation is never magic

Neutral formats do not preserve every proprietary feature tree, mate, drawing annotation or parametric relation. Always open the exported file in a second session or independent viewer and check geometry, units, assembly structure and missing faces.

Practical recommendation

Use the native CAD format for editable collaboration when both parties share the same CAD system. Use STEP as the default neutral mechanical exchange format, and IGES mainly when a specific downstream system requires it.