When you export a document from the SolidWorks application, you can set the options for the new file you create. The options vary, depending on the type of file.
To export a SolidWorks document as another file type:
Select one of the following:
The face or surface of a part in the graphics area
A solid body or surface body from the Solid
Bodies 
or Surface
Bodies 
folder in the FeatureManager design tree
The components of an assembly
NOTE: If you do not select any entities, the entire part or assembly is exported.
Click File, Save As.
The Save As dialog box appears.
Set Save as type to the desired file type, then click Options.
The Export Options dialog box appears with the desired file type selected on the File Format tab.
Set the appropriate options for the target file type. See the target file type below for the available options:
In the File name box, type a name. The extension for the selected format is added automatically when you save the document.
Click Save.
NOTES:
If you export an assembly that contains lightweight parts, the Resolve Lightweight Parts dialog box appears. You must resolve any lightweight parts before you can export an assembly.
If you export an assembly that contains hidden or suppressed parts, a message box appears asking if you want to resolve these parts. To export these parts, you must resolve them.
If you select any faces, surfaces, solid bodies or surface bodies of a part, the Export dialog box appears verifying if you want to export only the selected objects. Click Selected face(s) to export only the selected faces, Selected bodies to export only the selected bodies, or All bodies to export all solid bodies.