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Tips for Using Geomview

In order to use DsTool Tk's three dimensional viewing capabilities, you need to have access to Geomview. For information on using Geomview, see the documentation accompanying it. This section gives some tips which are specific to Geomview's interaction with DsTool. In order to use Geomview effectively with DsTool, you need to know how DsTool interacts with Geomview. Geomview is used for two purposes in DsTool: plotting and viewing three dimensional data, and doing animations. For three dimensional viewing, data previously computed by DsTool is sent to Geomview, where the user can view and manipulate the data. For animations, the data is sent to Geomview as it is computed, so that the animation can take place in real time. Here are some other helpful tips:
1.
You can scale the individual axes of a target sent to Geomview from DsTool using the external module ``Transformer'' . This module allows you to scale axes individually, or in groups. This feature comes in handy when you have data that has widely varying scales. While DsTool automatically compensates for these cases, Geomview does not.
2.
There are two basic types of animations  that are done with Geomview. The first type involves sending transformation matrices from DsTool to Geomview at each time step of an integration to change the position of the objects. The second type involves replacing the objects in Geomview with new ones at each time step. Due to the large amounts of data being passed from DsTool to Geomview, animations can be very slow, even for the first type. Therefore, when doing animations, you might want to lower the number of time steps taken or choose a faster integrator.
3.
You can delete trajectories or other data objects by using the ``Delete'' function (on the edit menu), but this option will delete only the target which is highlighted in the target menu. This target is also listed in the Target field of the Tools window. Selecting Delete when the target is ``World'' will delete everything. Deleting selected targets can be useful when for example you want to view the (un)stable manifold of a single fixed point. Since DsTool sends the computed stable and unstable manifolds of the fixed points individually, you can delete the ones you aren't interested in seeing. Alternately, you can delete the manifolds in DsTool before sending them to Geomview.
4.
You can overlay plots of variables  by using the 3-D View window and Geomview. For example, if you want to overlay plots of x vs. t, y vs. t and z vs. t, you can do this by the following procedure: First, send to Geomview (via the 3-D View window) the plot x vs. t vs. 0. Then copy the resulting Geomview target by selecting the Copy option from the Edit menu button. Next, send to Geomview the plot y vs. t vs. 0. Again, copy this resulting target. Finally, send to Geomview the plot z vs. t vs. 0. The resulting plot in Geomview will be the overlay of the three plots. If you fail to copy any of the targets, they will be erased. This is because DsTool sends trajectory objects to Geomview using the name ``Traj.n.m'', where n is the flow number, and m is the trajectory number. Since we're only using one trajectory to generate all three plots, DsTool sends the data to the same target name each time, writing over the previous data in that target.

next up previous contents
Next: Tips for the Tcl/Tk Up: Hints and Suggestions for Previous: Hints and Suggestions for
John Lapeyre
1998-09-04