File Handling and Formats

Summary of the file formats supported for CAD integration in SimSolid.

Proprietary Formats

SSP Format (.ssp)
The .ssp file is a SimSolid proprietary geometry, solution data and results format file. These files store all model data and are used to archive/save the complete project instance.
SSG Format (.ssg)
A .ssg file can be both imported and exported (saved) from the application. SSG is a SimSolid proprietary neutral file format containing model geometry and material properties.

CAD Integration

SimSolid is CAD integrated with the following:
  • SolidWorks
  • Autodesk Fusion 360
  • Onshape
For SolidWorks and Fusion 360, SimSolid uses CAD embedded plugins to seamlessly transfer geometry and material property data directly to SimSolid. A direct memory link is established between the CAD system and SimSolid to make this data transfer fast and efficient. All visible parts and assemblies are transferred.
Note: This requires that the CAD application is open and available on the same computer system. Since this is not always possible, the plugins provide the ability to write SimSolid SSG files as well.

Geometry Import

SimSolid also provides the ability to import 3D solids parts and assemblies from CAD files directly without requiring assistance from the CAD application. Surface and wireframe geometry is not imported.

Table 1 lists the file formats that are supported in SimSolid.
Table 1.
File Format Supported Versions
CATIA V4 (.model, .dlv, .exp) All 4.xx
CATIA V5 (.CATPart, .CADProduct) R10 to R32
CATIA V6 (.3Dxml) 2011to 2013x
3D Experience (.3Dxml) 2014 to 2020x
Inventor (.ipt, .iam) All to 2023
JT (.jt) 7.0 to 11.0
Pro/Engineer (.prt, .asm) 13 to Creo 9
ACIS (.sat) All to R27
SOLIDWORKS (.sldpart, .sldasm) 99 to 2022
STEP (.stp) 203/214/242
STL (.stl) Ascii/Binary
Parasolid (.x_t) All to 35
NX/Unigraphics (.prt) 11 to NX CR 2007
ECAD (.tgz, .tar, .zip, .pcb, .pcbdoc, .xml, .cvg)  
Altium (.pcb, .pcbdoc)  
IPC-2581 (.xml, .cvg)  

CAD Data Readers

Two CAD data readers are provided in SimSolid: Parasolid and Legacy. In most cases Parasolid is the preferred data path, but if issues are encountered, use the alternative reader.

Difference Between STL and SSG

In STL format assembly geometry is represented by triangles which are defined by XYZ coordinates of their vertices and do not contain any information about triangle's connectivity. STL geometry model is not water-tight. Gaps, overlaps, and triangle's incompatibility are possible. In case of assemblies, solids are not identified in an STL file of the assembly. Triangles of all solids are output in a continuous file without any separation. STL is a simplest standard format widely used in different industries.

SSG format is a proprietary format that represents geometry with the same triangles as STL format, but which contains additional information about the triangle's connectivity and about solids of an assembly. SSG geometry model is water-tight.