Nelson L. Johnson       

Senior Software Engineer

I have been involved with microcomputers since the late seventies, when I built my own 6502 CPU machine.  It had 16K of RAM, and persistence was achieved using an audio cassette.  I couldn't afford an Apple.

In 1981, I thought it would be fun to build my own microcomputer using the new 8080 chip that Intel was telling me about.  Those plans were thwarted, however, because soon afterward IBM introduced their Personal Computer.  I just had to go out and buy one!  I had saved all of $10,000, of which $4,000 was paid to ComputerLand for a printer and a machine that had two single sided floppy drives and 64K of RAM.  I was so eager that, to get me off their backs, ComputerLand took part of a shipment that was going to a major corporation and sold it to me!  Thus I became one of the first owners of an IBM PC.

I sat right down and started writing a 3D CAD system using Fortran I had written at Columbia University in 1973.  As an Architecture/Engineering student I had worked with Dr. Lou Katz and his wife Genevieve to start a cross-departmental program aimed at educating architecture students in the use of 3D graphics.  Dr. Katz was head of the Microbiology Department at the time, and later became president of Siggraph.  I had the opportunity to use an IBM 360 and a specialized custom high speed graphics machine, used to model molecular structures, to create a small CAD system in Fortran.  The system could display a perspective view of a wireframe model of a building.

So, after working as an architectural designer/drafter for several years, in early 1983 I quit my job as an associate in an architecture firm and started Computer Aided Design of San Francisco, with the first product MicroCAD, a 3D CAD system for the IBM PC.  It was the first CAD system on the IBM PC platform, predating AutoCAD by one year.  Autodesk was at first my competitor, but later on I marketed MicroCAD as the "true 3D" package for customers who wanted to be able to generate perspective views but were unable to do so using AutoCAD.  The MicroCAD offering took off, and within a year my new company Imagimedia Technologies, Inc. was a great success.  After Autodesk went public I became an Autodesk-affiliated developer.

In 1987 Osborne/McGraw-Hill published my first book, 'Advanced Graphics in C', which became a best seller and was translated into several languages.  The book described and gave C code examples using the interrupt structure of the EGA, the first IBM PC graphics adapter.  Included was the complete C language source for a program named GRAPHIQ.  The program used a unique bulletproof integer-based Bresenham's algorithm to draw lines.  Until then, to the best of my knowledge, the algorithm was always done in floating point.  In 1994 a programmer from Microsoft called me and said that I should be very proud.  My book was in the Microsoft programmer's library, and it had been used as a reference in writing the Windows OS!

My bible was 'Fundamentals of Interactive Computer Graphics' by Foley - Van Dam.  It introduced me to the exciting world of graphics programming, and I have not looked back since!

These days I am an independent consultant working on projects of all kinds, from enterprise development in Java to web development in C# .NET, but nothing compares to those early days when the core systems that are in use today to make sophisticated 3D graphics images were in their infancy.