SolidWorks has long supported *.stp or STEP import and export. STEP files are the most robust neutral file format available for exchanging model data between CAD systems. STEP is preferred over IGES (which is also fully supported but is an inferior format). Parasolid (*.x_t) and ACIS (*.sat) files are generally even more robust than STEP, but not as many other CAD systems support import/export of these proprietary, but common, file formats. STEP files are unable to contain feature history, therefore imported *.stp files will produce solids and surfaces only without parametric intelligence. Subassembly structures, component names, and colors are imported if they exist in the file. SolidWorks writes this data to STEP files.