This document describes how to access functionality that used to be reserved for the TwoHanded interface with the mouse.
This document is broken down into three major sections, one describing mouse based transforms, one describing subsetting with the mouse and one describing the volume cutting with the mouse.
Mouse based transforms are the default function for the mouse in SFA. That is, unlike the other mouse based functionality, you don't need to press a key on the keyboard to perform mouse based transforms. There are three major transform types available with the mouse: rotate, translate, and scale.
Rotation is performed by pressing the left mouse button and moving the mouse. As the user drags the mouse, it acts as a virtual trackball, allowing the user to rotate around all three axes simultaneously. Experimentation with this technique is the best way to learn how to use it.
Translation moves the scene along the X and Y axes with movement by the mouse in X and Y. The user presses and holds the middle mouse button, and drags the mouse left and right (for X translation) and up and down (for Y translation).
Scaling can be thought of as translation along
the Z axes. By pressing and holding the right mouse button and dragging
the mouse, the scene with either appear to get closer to the user or farther
away, depending on the mouse movement. This allows the user to bring the
scene closer to inspect an area more closely, or to move the scene away
to get a broader idea of the entire dataset.
Subsetting with the mouse is substantially different than subsetting with the trackers. Since the trackers are inherently three dimensional, and the mouse is not, we need to decompose the three dimensional task of creating a subset into two dimensions for interaction with the mouse.
Since the mouse buttons are reserved for transforms (see above), we need a way of distinguishing a subset sweep from transforms. The solution is to hold down the shift key while pressing and move the mouse.
To start sweeping out a subset with the mouse, hold down the shift key and press and hold the left mouse button. The first face the mouse cursor intersects is designated as the active face. Move the mouse along that face until the appropriate size has been reached, then release the mouse button.
There will now be a line stretching out from the active face to the opposite face. Move the mouse cursor along that line to move the starting face of the subset into the scene. Once you have located the starting face to where you want it, press the mouse button. Continue dragging down the line to add depth to the subset. Releasing the mouse button again finalizes the subset in place. Note that this sounds more complex than it is -- it will only take you one or two times doing this before you get the hang of it.
While a subset is being swept out, a partially transparent gray cube is drawn, indicating to the user the size of the subset they are creating. As soon as the subset has been completed, this cube is no longer drawn, to prevent the cube getting in the way of the data being visualized.
The other two mouse buttons (middle and right) are used for other purposes relating to subsetting. The middle mouse button is reserved for future work on dynamically resizing subset boxes with the mouse (not yet implemented). The right mouse button, when placed over a subset thumbnail, deletes that subset.
Multiple subsets are controlled through the use of thumbnail windows.
For a discussion on SFA subsetting and an explanation of thumbnails, please
see this
page.
See twohand doucmentation for a complete description of plate functionality (See the section on plates).
At this time, mouse based plates have not been implemented. We are hoping
these will be implemented shortly, at which time documentation will be
added.