3D Graphics File Conversion

IVCON is a C++ program which reads and writes a small variety of 3D graphics file formats, converting from one to the other.

This is by no means a perfect or even correct program! It was home-grown, and developed, as needed, to handle a particular set of files. It can make mistakes, or crash, rather more often than software you pay for, written by someone who knows what they're doing.

The supported formats include:

The program can be used in command line form, as in:

ivcon input.iv output.stl
or can be used in an interactive mode, in which input and output files can be read or converted in any order.

Graphics file formats are poorly documented; hence this program was written primarily by examining typical files and struggling to interpret them. Particularly in the case of Inventor and DXF files, the program is not able to handle all the subtleties of the file format, and may mangle data, or even crash.

Helpful corrections to the 3DS reader were supplied by John F Flanagan. The GMOD reader and writer were written and supplied by Zik Saleeba. Improvements to the DXF routines to handle polygon oriented files were supplied by Zik Saleeba. The 3DS reader is based on a program by Martin van Velsen, with the help of Gert van der Spoel.


The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

IVREAD, a FORTRAN90 program which can convert some 3D graphics files.

TEC_TO_OBJ, a FORTRAN90 program which can read a TECPLOT file describing a surface in 3D composed of triangles or quadrilaterals, and write an OBJ file.


  1. Adrian Bowyer and John Woodwark,
    A Programmer's Geometry,
    Butterworths, 1983.
  2. James Foley, Andries van Dam, Steven Feiner, John Hughes,
    Computer Graphics, Principles and Practice,
    Addison Wesley, Second Edition, 1990.
  3. 3D Systems, Inc,
    Stereolithography Interface Specification,
    October 1989.

Source Code:

Examples and Tests:

You can go up one level to the graphics source codes.

Last revised on 15 November 2006.