Free online STP to IFC converter

A STEP model must be delivered to a BIM application such as Revit, Archicad, or Solibri when a mechanical component needs to join a coordinated building model. Converting it to IFC also provides an application-independent exchange file for coordination and archiving.

What the STP format is

STP usually refers to STEP, the ISO 10303 neutral CAD exchange format. Files commonly use .stp or .step and are created by SolidWorks, CATIA, Siemens NX, Creo, Inventor, Fusion, FreeCAD, and other mechanical CAD systems.

STEP can store precise boundary-representation solids and surfaces, assemblies, product structure, colors, layers, and selected product metadata. It normally does not identify BIM entities such as walls, slabs, doors, spaces, storeys, systems, or building materials.

What the IFC format is

IFC, or Industry Foundation Classes, is an open BIM exchange format standardized as ISO 16739. An IFC model can contain building and infrastructure objects, spatial containment, relationships, properties, quantities, materials, placements, and geometry for coordination software including Revit, Archicad, Tekla, Allplan, Solibri, and Navisworks.

IFC is appropriate when the recipient needs model coordination, clash checking, quantity extraction, or long-term exchange without the original CAD application. Choose the schema required by the receiving system: IFC4 is generally preferable for new exchanges, while IFC2x3 remains necessary for some established workflows. Infrastructure projects may specify IFC4.3.

How to convert the file

CAD Exchanger is a direct desktop option because it can import STEP and export IFC without a BIM authoring application.

1. Open the .stp or .step file and inspect the assembly tree for missing or merged parts.
2. Confirm the source units, model scale, orientation, and origin. Resolve unit or placement errors before export.
3. Use File → Export, select IFC, and choose IFC4, IFC2x3, or another schema specified by the recipient.
4. Map available object types or properties if the exporter provides those options. If geometric accuracy or tessellation settings are available, use a finer setting for curved surfaces and a coarser setting only when file size or processing time is a constraint.
5. Save the result as model.ifc. Open it in the target BIM or coordination application and check scale, orientation, placements, visibility, colors, part count, and object properties.

For a free desktop workflow, open the STEP file in FreeCAD with File → Open, inspect and rename the imported objects, then use the BIM or Arch workbench and its IFC export command. FreeCAD’s IFC capabilities depend on the installed workbench and IfcOpenShell version. A selected imported STEP solid is normally exported as generic IFC geometry, not automatically classified as a door, wall, equipment item, or other native BIM object.

FME Form is suitable for controlled batch workflows when a team needs to read CAD data, map attributes, transform coordinates, and write IFC through a configured workspace. Test the exact STEP variant and IFC schema with the installed FME version before production processing; complex assembly semantics may require custom mapping.

For non-confidential files, a reputable hosted option such as CAD Exchanger Cloud can be used if its current service supports both the uploaded STEP variant and the required IFC export. Upload the file, select IFC and the required schema, download the result, and validate it in the recipient’s software. Do not submit proprietary engineering or personal data without checking the service’s retention, access, and deletion terms.

Quality and compatibility limitations

A direct conversion usually transfers shape geometry rather than design intent. The result may contain IfcBuildingElementProxy, IfcProduct, or another generic entity, so BIM software may not treat the model as a door, wall, structural member, or equipment object.

STEP assemblies can be flattened, split, or reorganized during export. Part names, colors, layers, metadata, and assembly relationships may be lost or mapped differently. IFC geometry can also be represented with boundary-representation, swept-solid, or tessellated forms, and different importers support these forms inconsistently.

Before conversion, remove construction geometry, suppress unnecessary parts, repair invalid solids, and verify units. After conversion, check the IFC schema, coordinate system, global placement, object count, geometry tolerances, materials, colors, assembly hierarchy, and property sets. Compare several critical dimensions with the source model.

If the deliverable requires native BIM classification, reliable quantities, fire ratings, manufacturer data, editable parametric behavior, or discipline-specific property sets, use the STEP file as reference geometry and classify or remodel it in Revit, Archicad, FreeCAD, or another IFC-aware BIM application. Mechanical CAD geometry alone does not contain enough information for a converter to infer those requirements reliably.