Diffpack Online

Diffpack GUI: Data Visualization

The Diffpack GUI embeds Vtk (Visualization Toolkit) for state-of-the-art visualizations. In order to interact with the scalar and vector fields generated by a Diffpack application, you can use the SimRes Browser to pick relevant data sets and produce nice graphics in the display.

Below you will find descriptions of different visualization options that can accessed through the Diffpack GUI. These are:

General
Camera
Light
Color preferences
Colormap
Extract
Surface
Contour/isosurface
Slice
Vector
Animation
Export field(s)
Save image(s)
Legend

	The check boxes allow you to turn on/off the coordinate axes, the geometry outline and the legend. Moreover, you can tell the rendering engine not to reset the camera position when changing the visualization parameters. The information field provides a description of the current data set.
	You are allowed to choose between a range of predefined camera positions, as well as manipulating the scene by changing the azimuth, elevation and roll values, separately or in combination. Alternatively you can manipulate the scene interactively in the rendering window (drag the mouse with the left button down). The zoom buttons allow you to zoom in and out in predetermined steps. This can also be done in the rendering window (drag the mouse with the right button down).
	Here, you can switch to positional light, specifying the origin and focus, as well varying the intensity of the light source.
	Using the sliders for Red, Green and Blue you can change the color of either the light or the background in the rendering window. By using the check box "Lock channels", the levels of red, green and blue will all be the same, causing different levels of grey. The lowermost buttons provide shortcuts for the colors white and black.
	Using the sliders to change the minimum and maximum values for the color mapping, you can tailor your visualization to focus on the interesting parts of the data. The lowermost slider allows you to set the ranges for the sliders determining the extreme values of the colormap.
	Using the sliders you can restrict the visualization to the volume of interest, i.e., extract a subset of the data that is of particular interest. It might be useful to tick off the check box for grid outlining, giving you the bounding box for the complete geometry. You will have to press the "Apply" button to actually do any extraction. Keeping the "Apply" button pressed, you can interactively change the parameters and observe the immediate effect. On low performance machine this might be a somewhat time-consuming process, and in that case it is recommended to keep the "Apply" button off until reasonable values have been set.
	By varying the slider value or entering a numerical value, you are allowed to scale the surface elevation. This control is similar to the surface scaling available in the SimRes Browser. However, unlike the browser scaling control, this one does not alter the underlying data but rather set scaling parameters in the rendering engine. The "Reset" button brings the original scaling.
	Depending on whether you are dealing with 2D or 3D data, you can generate contour plots of isosurfaces. The sliders are used to set the number of levels and the extreme values for the interval to be contoured. As for the data extraction, you may see immediate effects as long as the button "Apply" is pressed.
	For 3D data you can slice the volume arbitrarily by specifying a point in the slice plane and its normal vector. As for the contouring and data extraction, you may see immediate effects as long as the button "Apply" is pressed.
	When dealing with vector fields, you may scale the hedgehogs arrows using the slider or by entering a numerical value. This control is similar to the vector scaling available in the SimRes Browser. However, unlike the browser scaling control, this one does not alter the underlying data but rather set scaling parameters in the rendering engine. The "Reset" button brings back the original scaling. You may choose between different vector visualization effects like hedgehogs (default), stream tubes and stream ribbons.
	For time-dependent problems, a sequence of (temporal) data sets might be combined as an animation. Choose the data set in the SimRes Browser, and select the start and end frame numbers. You may set the animation to loop, or you can control it by the "Play", "Pause" and "Stop" buttons. It might be advisable to tick off the "Do not reset camera" check box to prevent rescaling of the data between animation frames.
	These tools allow you to export Diffpack results (in SimRes format) to external file formats, including VRML, UCD (used by AVS and IRIX Explorer), VTK, Matlab, and PlotMTV (Unix only).
	These tools allow you to save the current rendering as an image, either as PPM, TIFF or BMP files.
	Changing these parameters you may customize the layout and location of the legend. In particular, you can change the number of color levels and format of the numbers printed on the legend bar.