Re: Simulation Visualization

Hi Nick,

> I'm thinking of using VisAD for run-time visualization as part of a
> simulation framework. The simulation is "tick-based" such that some
> computation occurs each tick, data is generated and then visualized. So
> the visualization is dynamic and updated each tick. From a brief scan
> through the mailing list archives it looks like VisAD would be suited
> for this. Is it? Has anybody done anything similar?
> I have been using sequence charts and bar graphs from JClass, but they
> aren't giving me the flexibilty I need.

If you are running on Sparc Solaris, you can run:

  java visad.aune.ShallowFluid

This steerable 2-D shallow fluid model is distributed with
VisAD.  It links to the Fortran fluid model via JNI (Java
Native Interface), and calls the Fortran once per time step.
You can watch the simulation run, or you can use sliders to
vary things like gravity and watch the consequences.

Once you link a VisAD Data to a Display, via a DataReference,
then the Display updates its depiction of the Data whenever
the Data value changes (or whenever the DataReference is
aimed at a new Data object).  If the Display rendering cannot
keep up with the changes to the Data then you won't see every
time Data change.  However, you can create a DisplayListener
that waits for the Display to update before allowing the model
to compute the next time step, if you want.

You can also link a VisAD Data to a computation coded in a
VisAD CellImpl, in which case the computation is triggered
whenever the Data changes.  Thus CellImpls can be used to
chain computations, and is used in the VisAD SpreadSheet for
this behavior.

Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738