Visualizing the Data

Once the data file has been opened and the appropriate field attribute for both scalars and vectors has been chosen one can either filter the data or one can directly apply a module to the data and visualize it. MayaVi provides a large number of Modules and a few Filters. They are described in more detail subsequently.

In order to Filter the data one must use the Visualize menu and from the Filters sub-menu choose the appropriate filter. As soon as a filter is requested a popup window will appear that helps you configure the particular filter. Please note that it is not at all necessary to filter the data. If no filtering is required one does not need to load any filter. Even if a filter is used one can delete it at any time using the controls provided in the control panel.

In order to use a particular visualization module a procedure similar to the one for Filters is used. One merely uses the Visualize menu and from the Modules sub-menu chooses the appropriate Module. The module might take a little while to load. If there is some kind of error a warning dialog will attempt to describe the problem and hopefully the user can correct the situation.

Navigating the Visualization

It is important to be able to navigate the data and view it appropriately. In MayaVi this is achieved in one of two ways. Using the standard view mode buttons provided at the bottom of the visualization widget or by using the mouse to navigate through the visualization. The mouse based navigation is far more powerful and general purpose. The buttons however provide quick shortcuts to commonly desired views. The buttons and the visualization widget are shown in the illustration in an earlier chapter.

Navigating using the mouse

Mouse navigation is powerful but takes a little getting used to. It is relatively simple and with experience can be used easily. This section briefly describes how one can use the mouse to navigate through the data.

Rotating the visualization

With 3D visualization it is important to be be able to rotate the visualized scene. In MayaVi this is achieved by first placing the mouse pointer on top of the visualization window. Then one keeps the left mouse button pressed and drags the mouse pointer in the direction one needs to rotate the scene. This is very much like rotating an actual object.

Zooming in and out

To zoom in and out of the scene first one places the mouse pointer inside the visualization window. To zoom into the scene one keeps the the right mouse button pressed and drags the mouse upwards. To zoom out of the scene one keeps the right mouse button pressed and drags the mouse downwards.

Panning the scene

To pan a scene implies translating the center of the rendered scene. In MayaVi this is done in two ways.

  1. By keeping the left mouse button pressed and simultaneously holding down the Shift key and dragging the mouse in the appropriate direction.

  2. By keeping the middle mouse button pressed and dragging the mouse in the appropriate direction.

Just practice this a few times and you should get used to this pretty easily. This practically covers all that you need to know to be able to use MayaVi effectively. The best way to really learn about MayaVi is to explore the various options and try them out. Subsequent sections provide more details on the various menu's provided and the various modules and filters that are available.