CAD Format Types

CAD Formats

This CAD formats listing is broken into four areas:

  • Native CAD Formats
  • Geometric Modeling Kernels
  • Neutral CAD Formats
  • Tessellated formats

‘Precise’ refers to any kind of CAD model, whereas ‘Tesselated’ refers to polygonal models. See end of this page for further clarification.

Please note that ‘TransMagic Read’ and ‘TransMagic Write’ capabilities refer to TransMagic Expert. See specific capabilities of each core product at the bottom of this page.

Native CAD Formats

Native CAD Formats refers to formats that are proprietary to specific CAD systems. If you have the ability to read these formats, they will have the most information and be more accurate than Geometric Modeling Kernel formats or Neutral CAD formats.

For this reason it’s always a good idea to ask your customer for the native format (assuming you have the capability to read the the native format).

Format Extensions Precise or Tessellated Vendor TransMagic Read TransMagic Write Notes
AutoCAD .dwg, .dxf Both Autodesk R9-2018 R9-2018 DXF is ASCII
CATIA V4 .model Precise Dassault 4.1.9 – 4.2.4 4.1.9 – 4.2.4
CATIA V5, V6 CATPart, CATProduct, CGR Both Dassault 15-2018 (R28) 15-2018 (R28) File-based support for V6. Note that CGR is Visrep.
Creo .prt, .asm Precise PTC Up to 4.0 TransMagic can also read Pro/E files, see separate reference below.
Microstation .dgn Precise Bentley Systems Up to V8
NX, Unigraphics .prt, .jt, .j_t Precise Siemens NX up to NX12, JT up to 10.1 JT up to 10.1 JT is a compressed visualization format ideal for viewing large assemblies. JT files can be Brep, or Brep and Visrep both.
Pro/E .prt, .asm Precise PTC Up to Wildfire 3
Inventor ipt, iam Both Autodesk Up to 2018
SOLIDWORKS .sldprt, .sldasm Both Dassault 97-2018 97-2018 Writing SOLIDWORKS format requires that the version of SOLIDWORKS you want to write to is actively licensed on the same machine.
Solid Edge .par, .asm, .psm Both Siemens ST10 Best exported as X_T.


Geometric Modeling Kernels

Geometric Modeling Kernels are what Native CAD formats are built upon. Because these formats are strictly managed by the vendors, they are a better source of geometric information than STEP or IGES.

Format Extensions Precise or Tessellated Vendor TransMagic Read TransMagic Write Notes
ACIS .sat, .asat, .sab, .asab Both Spatial Technologies R1.5-R2017 (R27) R1.5-R2017 (R27) SAT is ascii, .sab is binary, and .asat and asab are specifically for assemblies. ACIS supports Non-Manifold geometry.
Parasolid .x_t Precise Siemens Up to 30.0 Up to 30.0 Parasolid supports only manifold geometry. Read more about Manifold and Non-Manifold here.
SMLib .sms, .iwb, .iwp Precise Solid Modeling Solutions All Versions All Versions


Neutral CAD Formats

Neutral CAD formats are the lowest-common denominator between CAD systems. If your customer does not have the software to read the native CAD file or the geometric modeling kernel format, STEP is your best bet.

Format Extensions Type Managing Entity TransMagic Read TransMagic Write Notes
IGES .sat, .asat, .sab, .asab Precise ANSI / ASME Up to 5.3 Up to 5.3 International Graphics Exchange Format; this format primarily supports surfaces and is generally the weakest of the translation formats.
STEP .stp, .step Both ISO AP203/AP214, AP242 AP203/AP214, AP242 STEP is the most popular neutral CAD format in the world today, but STEP is not always the best go-to format for translation.


Tessellated Formats

CAD formats are often converted to polygonal formats such as STL and OBJ for the purposes of 3D printing, animation or game development. Polygonal formats are tessellated, or faceted, and as such are an approximation, containing none of the engineering information found in Brep CAD models, such as weight or volume. Note that we have also included NGRAIN’s voxels in this list since, like polygons, voxels are an approximation of CAD geometry.

Format Extensions Precise or Tessellated Vendor / Managing Entity TransMagic Read TransMagic Write Notes
3DXML .3dxml Tesselated Dassault Up To R2016 (v4.3 internal version) Up To R2016 (v4.3 internal version)
3D PDF .pdf Tesselated Tetra 4D Up to 1.7 3D PDF is an ideal format for sharing information with people who don’t have a CAD system or a CAD viewer; all you need to view a 3D PDF file is Adobe Acrobat Reader, which almost everyone has.
OBJ .obj Tesselated Wavefront All Versions All Versions Obj is a format commonly used for exchanging information between modeling and animation systems such as 3ds Max and Maya.
Collada .dae Tesselated ISO All Versions All Versions
NGRAIN .3ko Voxel Ngrain Up to version 4.1 Voxels are actually a type of 3D pixel; they don’t really fit into any of the standard categories well, so we put them here. Voxels are good for allowing technicians and mechanics to visualize, maintain and service large, complex 3D assemblies such as automobiles and aircraft.
PLY .ply Tessellated Stanford University All Versions All Versions
POD .pod Tessellated All Versions All Versions
Stereo Lithography .stl Tessellated 3D Systems All Versions All Versions STL is the default format for 3D printing. STL files can be optimized using export settings, or via the Polygon Reduction tool.
VRML .wrl Tesselated WWW3 1.0 & 2.0
WebGL .html Tesselated WWW3 1.0 & 2.0 WebGL files are viewable and rotatable in any HTML5-supported browser with no plugins necessary, making them ideal for online parts libraries.


Precise vs Tessellated Models

STL Optimization

‘Precise’ models are CAD Brep (Boundary Rep) models, with precise geometric boundaries and capable of mass properties calculations.

‘Tessellated’ models are polygonal, or Visrep (visual representation), useful for visualizing models or assemblies, though faceted in nature. Read more about Brep vs Visrep here.

The figure at right (moving from left to right) shows a CAD model (in purple), a faceted STL model, and a very roughly faceted STL model. Notice that there are no straight lines, or ‘facets’ on the CAD model. CAD models are geometrically precise, which is why they are sometimes referred to as ‘precise’ models. Tessellated or faceted models, on the other hand, are composed of triangles, and are mere approximations of the model, even if it they are so finely faceted that it is sometimes difficult to tell.


Specific Read / Write capabilities

  • All TransMagic core products read polygonal, neutral, geometric modeling kernel and native formats.
  • TransMagic EXPERT writes polygonal, neutral, geometric modeling kernel and native formats.
  • TransMagic PRO writes polygonal, neutral and geometric modeling kernel formats.
  • TransMagic SUPERVIEW writes only polygonal formats.

Click this link to download a PDF snapshot of this document. Note that this web page will always be more up-to-date than PDFs.


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Origin International
We used TransMagic on an 80 MB CATIA file that choked another translator. It translated the file in just 14 minutes!
– J. B., Origin International

Superlift/Black Diamond Suspensions
Until TransMagic I had become almost used to working with damaged files, and never realized I was missing more than just a few surfaces!
TransMagic has made it possible to open any native CATIA file or version I receive, quickly isolating, repairing and retrieving what I need.
Once native files are saved in a TransMagic format, opening and handling even a large file is surprisingly fast.
Having its own tools in TM is also efficient at making repairs to missing surfaces, before translation.
Repairing damaged files and grouping what I need prior to importing, has saved me lots of time. My time is now better spent, working with clean and manageable files that I can rely on as I design new products.
Thank you TransMagic!
– K. D., Superlift/Black Diamond Suspensions

Sunset Tool
We put TransMagic to the test with an older IGES file. We even tried to send this IGES file out to be healed, only to be told it was too bad. We ran it through TransMagic and were able to get a usable file that was 100 times better. I’m putting in my request to purchase today.
– R. M., Sunset Tool