Peter Young
Visualisation Research Group


Select the above image to enter the 3D visualisation
or you can view the full size image shown above.

About Axles

Axles provides a representation for the various functions in a program. The primary goals of the Axles representation is to provide a very distinctive and individual appearance for teh functions while incorporating useful information on them, in this case the code structure and simple metrics data. Axles is not a visualisation, it is a representation and is intended to be used within a larger visualisation, for example CallStax.

The CallStax visualisation highlighted a need for distinctive and individual representations of the components of the stax, in this case functions. Axles provides a very distinctive appearance for the functions, but unfortunately suffers a number of disadvantages which make it unsuitable for inclusion in CallStax. For example:

The Towers representation attempted to address the problems of Axles, and more specifically provide a representation for use with CallStax.

The construction of the Axles representation is extremely simple. Each representation is composed of a number of nested ‘spines’ or ‘axles’. Each level or axle represents a different scope of the function. For instance, the top level axle represents the function scope while a nested blue axle represents a while loop within that function. The colour of each axle plays an important role in that it defines the type of scope, i.e. while loop, for loop, conditional true and conditional false. An annotated diagram is provided which describes the various features.

About the demo

In order to view this demo visualisation you will require a browser with Superscape's Viscape VR plug-in installed. It would also be an advantage to have a high color display configured.

There is very little point in viewing this demo using Viscape as all the features are evident from the screenshot shown above and from the annotated diagram also described above.

Navigation through the 3D environment can be facilitated simply by using the directional control icons at the bottom of the frame. Alternatively, a more efficient though trickier control method can be activated by selecting the 3D frame then pressing the space bar. This produces a white box called the dead zone. Moving the mouse out of this box will result in movement through the 3D world. Various methods of movement can be facilitated by using the left and right mouse buttons in conjunction with moving the pointer. The left mouse button allows rotation control over pitch and yaw (i.e. turning on the spot) and the right mouse button allows translation horizontally and vertically (moving left/right, up/down while facing the same direction).

This page is maintained by Peter Young, please send any comments, jokes, insults or general abuse to (

Last updated: Monday 19 May, 1997.