FixtureNet

FixtureNet made the Brost-Goldberg algorithm available via the Web in the Summer of 1994. To our knowledge, this was the first fixture design system on the Web. FixtureNet allows the user to enter a part using the mouse in a browser to click on each vertex of the part. When done, the user clicks on a button to submit the part to a server machine running at the authors' institution. The server computes all possible fixtures and returns images of them to the user's browser.

FixtureNet is composed of two major components: the fixturing programs and a collection of CGI programs [December and Gingburg, 1995] that interact with the fixturing programs. The fixturing programs are composed of a server program that accepts commands over TCP/IP connections and the actual fixturing engine. Both of the fixturing programs are written in Visual Basic from Microsoft and consequently run only under Microsoft Windows (3.x, 95, and NT).

FixtureNet has no real client-side component. It was targeted for version 1.2 of Netscape before support for Java was added. This means all processing of input and rendering of output is done via CGI programs running on the server machines. The CGI programs generate GIF files to represent the part and the work space, and these are interpreted by the browser as image maps to capture the mouse click locations.

Although FixtureNet provides a fairly complete interface for defining parts and displaying solutions, it is slow due to:

• Part input is based on CGI programs such that each mouse click runs a new instance of the CGI program. This is slow and resource intensive.
• In addition to invoking the CGI programs on each mouse click, there are two HTTP connections that must be created and destroyed: one for the HTML file returned by the CGI program and one to retrieve the GIF file generated by the CGI program and reference by the HTML document.
• These GIF files contain a large amount of data compared to the amount of data needed to represent the coordinates of the mouse click. This can be slow, especially on slow network connections like modems.