The interactive SpringEmbedder viewer allows you to modify most
of the parameters responsible for the dynamic behavior of the
spring embedding algorithm along the lines of
    Thomas Fruchtermann and Edward Reingold:
      Graph Drawing by Force-directed Placement.
      Software Practice and Experience Vol. 21, 1129-1164 (1992), no. 11


The spring embedding algorithm uses a physical model, where
the edges (springs) try to reach a given length. Nodes which
are not connected repulse each other. The forces exerted on 
the nodes will force them to an equilibrium configuration.

You can hold down the 'p' key and move nodes to change the
starting configuration of the springembedder. To recalculate 
an embedding, press the 'Recompute' button.

You can also fix vertices to a preferred position. To fix one vertex
you have to drag it to your preferred position, using the 'p' key,
and then mark it, using the 'm' key. Points may be released using the
'u'-nmark key. These marked vertices will not move in the spring 
embedding process.

The panels on the bottom of the frame allow you to change
some parameters:

Animation Steps:
  Specify after how many iterations of the spring embedding a
  result is displayed. The stop button allows you to stop a
  running animation. To continue press the "Recompute Points"
  button. The sliders cannot be changed during the animation.

Viscosity:
  The viscosity of the 3-dimensional space. A higher viscosity will
  make it harder for the nodes to move.

Inertion:
  The inertion of the nodes.

Repulsion:
  The repulsion of the nodes, which are not connected.

Orientation:
  If the nodes already have an embedding in $R^d$ and there is a linear
  objective function defined in the coordinate space, it can be used to
  rearrange the 3-d embedding along the z-axis corresponding to the
  objective function growth. The value will change the influence of
  the linear objective on the embedding.

Reset: 
  The nodes will be placed randomly on the unit sphere and the sliders
  will be reset to the startup custom values. To recalculate a 3-d 
  embedding press <Recompute>.

Recompute:
  The spring embedding algorithm will recompute an embedding of the
  graph. The actual point configuration will be used as the starting
  configuration of the algorithm.