What's the difference between STEP AP203, AP214, and AP242?

These are different STEP application protocols. AP203 (configuration controlled) is the legacy mechanical standard. AP214 adds automotive-specific data (colours, layers). AP242 is the modern combined protocol used for new exports — including PMI (product manufacturing information) and tessellated geometry.

Can I open a STEP file for free?

Yes. FreeCAD, eDrawings Viewer, and Open Cascade-based viewers all read STEP for free. For editing, FreeCAD and Fusion 360 (free for non-commercial) are the most accessible.

Software That Opens & Edits STEP Files (11 Tools, 2026)

STEP (ISO 10303) is the international standard for exchanging 3D solid CAD data. Unlike DWG/DXF, STEP captures real B-rep solid geometry — meaning the receiving CAD tool gets the model's solid topology, not just surface meshes. This makes STEP the default format for cross-vendor mechanical design (SolidWorks ↔ Inventor ↔ Creo ↔ NX), and increasingly for 3D printing and CAM workflows where the kernel needs to do real surface analysis.

Full read & write support (11)

AD
Altium DesignerRead & Write
from $3850 · Windows · ★ 4.9
The professional standard for PCB and electronics design.
O
OnshapeRead & Write
from $1500 · Web / iOS / Android · ★ 4.9
The professional CAD system built for agile cloud development.
R3
Rhino 3DRead & Write
from $995 · Windows / macOS · ★ 4.9
The industry standard for complex NURBS modeling and computational design.
S
SolidWorksRead & Write
from $1295 · Windows · ★ 4.9
The de-facto industry standard for 3D parametric mechanical design.
A
AutoCADRead & Write
from $255 · Windows / macOS / Web / Android / iOS · ★ 4.8
The global industrial standard for 2D drafting and 3D modeling.
F3
Fusion 360Read & Write
from $85 · Windows / macOS / Android / iOS · ★ 4.8
The cloud-native powerhouse for integrated CAD, CAM, and CAE.
PC
PTC CreoRead & Write
from $2430 · Windows · ★ 4.8
The original parametric 3D CAD powerhouse.
SN
Siemens NXRead & Write
from $6000 · Windows / Linux · ★ 4.8
Powerful high-end CAD/CAM/CAE suite for advanced manufacturing.
AI
Autodesk InventorRead & Write
from $315 · Windows · ★ 4.7
Professional-grade 3D mechanical design and simulation.
C
CATIARead & Write
from $4500 · Windows · ★ 4.7
The high-end PLM standard for Aerospace and Automotive engineering.
F
FreeCADRead & Write
Free · Windows / macOS / Linux · ★ 4.2
The premier open-source 3D parametric modeler.

Frequently asked

What's the difference between STEP AP203, AP214, and AP242?: These are different STEP application protocols. AP203 (configuration controlled) is the legacy mechanical standard. AP214 adds automotive-specific data (colours, layers). AP242 is the modern combined protocol used for new exports — including PMI (product manufacturing information) and tessellated geometry.
Can I open a STEP file for free?: Yes. FreeCAD, eDrawings Viewer, and Open Cascade-based viewers all read STEP for free. For editing, FreeCAD and Fusion 360 (free for non-commercial) are the most accessible.

Full read & write support (11)

Frequently asked

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