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.

3D Solid & B-Rep Standard26 verified tools

Software That Opens & Edits STEP Files (26 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 (26)

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.
3
3DEXPERIENCERead & Write
from $5000 · Windows / Web · ★ 4.3
Dassault Systèmes' cloud-based collaborative platform that unifies design, engineering, simulation, and manufacturing through virtual twin technology.
P
PowerMillRead & Write
Subscription · Windows · ★ 4.3
Autodesk's advanced CAM software for CNC programming, specializing in 3- and 5-axis manufacturing for complex parts in aerospace, automotive, and toolmaking industries.
F
FreeCADRead & Write
Free · Windows / macOS / Linux · ★ 4.2
The premier open-source 3D parametric modeler.
F
FORANRead & Write
Perpetual · Windows · ★ 4.0
Siemens' integrated CAD/CAE/CAM ship design software for marine vessels, covering concept design through production to operations.
P
PAM-STAMPRead & Write
Perpetual · Windows · ★ 3.9
ESI Group's sheet metal forming simulation software using finite element analysis for stamping process optimization and spring back compensation.
T
think3Read & Write
Perpetual · Windows · ★ 3.4
Italian 3D CAD software (ThinkDesign) with hybrid modeling, Global Shape Modeling (GSM), and 2D/3D integration for product design and engineering.
C
CADVisionRead & Write
Perpetual · Windows · ★ 3.1
Indian CAD software development company providing CAD solutions, product development services, and custom CAD software for engineering and design applications.
AE
AVEVA E3D DesignRead & Write
from $8000 · Windows · ★ 0.0
Advanced 3D plant design and engineering software for process, power, and marine industries with intelligent modeling capabilities.
DM
DesignSpark MechanicalRead & Write
Free · Windows · ★ 0.0
Free 3D CAD software for mechanical design with access to extensive component libraries and manufacturer support.
K
KOMPAS-3DRead & Write
from $3150 · Windows · ★ 0.0
Professional 3D CAD software for mechanical engineering with parametric modeling, solid/surface/sheet metal design, and integrated analysis tools.
MC
midas CivilRead & Write
from $5000 · Windows / macOS · ★ 0.0
Advanced structural analysis and FEM software for civil engineering, bridge design, and infrastructure projects.
MG
midas GenRead & Write
from $4000 · Windows / macOS · ★ 0.0
General-purpose structural analysis and FEM software for building design, architecture, and general engineering applications.
O
OrCADRead & Write
from $2500 · Windows · ★ 0.0
Cadence's professional PCB design suite featuring PSpice simulation, schematic capture, and high-performance routing for electronic design automation.
PP
PADS ProfessionalRead & Write
from $8000 · Windows · ★ 0.0
Siemens EDA's comprehensive PCB design solution for mid-to-high complexity designs with advanced simulation and analysis capabilities.
P
PulsonixRead & Write
from $800 · Windows · ★ 0.0
Affordable, powerful, and intuitive schematic capture and PCB design software for professional electronic design automation.
TC
T-FLEX CADRead & Write
Perpetual · Windows · ★ 0.0
Full-function parametric CAD software with Parasolid-based 3D modeling, powerful 2D drafting, and integrated analysis tools for mechanical design.

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STEP Solid Geometry Integrity Matrix

Standard 1Solid B-Rep Topology: STEP preserves mathematical solid boundary representations. Receiving kernels can perform accurate volume calculations and cross-sectional cutouts.

Standard 2PMI Metadata: STEP AP242 carries Product Manufacturing Information, embedding tolerance bands, surface finish symbols, and GD&T directly into the 3D model.

Standard 3Sewing Tolerances: If a STEP import shows open shells instead of water-tight solids, adjust the kernel's sewing tolerance (typically 0.01mm to 0.001mm) to stitch open boundary edges.

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.

Need a specific conversion?

Our interactive CAD Matchmaker filters all 26 STEP-compatible platforms against your budget, hardware configuration, and precise parametric drafting needs.

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Full read & write support (26)

Frequently asked

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