3D Step Viewer – ABViewer 9
Professional 3D Step Viewer to import and read *.stp and *.step format files. 3D Step Viewer can print and convert STEP to BMP and other formats.
Free to use additional library is required for IGES and STEP/STP formats (7.5 MB):
http://www.cadsofttools.com/download/converter3df.zip
STEP - STandard for Exchange of Product model data - ISO 10303 standard which is commonly used in industry.