The gem3Ddraw User interface

The gem3Ddraw main window shown in the picture is divided into several sections:

• file selection
• presentation
• algorithm parameters

File Selection

The left-hand side of the gem3Ddraw window offers the selection of several pre-defined application graphs. These are

C-60 molecule, aka soccer ball or buckminsterfullerene

a highly symmetric graph with |V|=60 vertices and |E|-90 edges.

Petersen graph,

a notoriously difficult graph to draw, as it violates most aesthetics criteria known in the area of graph drawing.

binary tree

of height h=7 with |V|=127 vertices.

3-D lattice

a large, symmetrical graph

iterated K_12

two complete graphs of size 12, connected with over 500 edges.

two symmetric graphs

contained in the paper of Fruchterman and Reingold on spring-embedder algorithms.

5-D hypercube

try to find the 4-D subcubes ...

any graph

opens up a file selector box, allowing the user to choose a graph of his own, using the file format

Presentation

fog

switches additional depth cue on/off. Turning it on makes a vertices in the background darker, emphasizing those in front.

orthogonal

switches orthogonal projection on/off. Turning on may save some computation time at the expense of depth-perception.

draft

switches draft mode on/off. In draft mode, all vertices are drawn as tetrahedrons, improving navigation in large data sets.

Gem parameters

Note: This option should be used only by persons familiar with the original paper (Frick, Ludwig, Mehldau 1994) (see references) on the Gem algorithm. The following options are available:

alpha_osc

modify opening angle for oscillation detection. Valid entries: [0..Pi/2].

alpha_rot

modify opening angle for rotation detection. Valid entries: [0..Pi/2].

sigma_osc

modify sensitivity towards oscillation. Valid entries: [0..1].

sigma_rot

modify sensitivity towards rotation. This value is normally computed from the graph structure. Valid entries: [0..1].

gravity

gravitational constant to keep disconnected subgraphs together. Default: 0.1

Rounds

number of rounds to iterate. By default, the value is computed from the number of vertices in the graph. It should not be chosen < |V|.

absolute/relative temperature

cooling strategy. By default, the cooling schedule tempers down to a relative fraction of the original temperature.

randomization on/off.

This parameter By default, randomization is on.

References

• A. Frick, A. Ludwig and H. Mehldau: A fast adaptive layout algorithm for undirected graphs, Proceedings of Graph Drawing'94, LNCS 894, Springer Verlag 1995. The code is available here. It has been generously made publicly available by A. Ludwig.
• T.M.J. Fruchterman, E.M. Reingold. Graph Drawing by Force-directed Placement. Software--Practice and Experience, 21,1991.