28.5.1 Using the Line Tool

The line tool allows you to interactively fine-tune the definition of a line or rake using graphics. Starting from an initial line, you can translate, rotate, and resize the line until its position, orientation, and length are as desired. For example, if you need to position a rake surface just inside the inlet to a duct, you can start with the line tool near the desired location (e.g., on the inlet), and translate, rotate, and resize it until you are satisfied. (You may find it helpful to display mesh faces to ensure that the line tool is correctly positioned inside the domain.)

Initializing the Line Tool

Before turning on the Line Tool option, set the End Points to suitable starting values. You can enter values manually, or use the Select Points With Mouse button. Often it is convenient to display the mesh for an inlet or isosurface on or near which you wish to place the line or rake surface and then select two points on that mesh to specify the initial position of the line tool. Once you have specified the appropriate End Points, activate the tool by turning on the Line Tool option. The line tool will appear in the graphics window, as shown in Figure  28.5.2.

Figure 28.5.2: The Line Tool

You can then translate, rotate, and/or resize the line tool as described below.

Translating the Line Tool

To translate the line tool in the direction along the red axis, click the mouse-probe button (the right button by default--see Section  29.3 for information about changing the mouse functions) anywhere on the "line'' part of the tool (see note below) and drag the mouse until the tool reaches the desired location. Green arrows will show the direction of motion.

Do not click on the axes of the line tool that have arrows on the ends. These axes control rotation of the tool. Click only on the portion of the tool that represents the prospective line surface. This portion is designated by the rectangles attached to each end.

To translate the tool in the transverse directions (i.e., along either of the axes within the plane perpendicular to the red axis), press the <Shift> key, click the mouse-probe button anywhere on the "line'' part of the tool (see note above), and drag the mouse until the tool reaches the desired location. Two sets of green arrows will show the possible directions of motion. (In 2D, there will be only one set of green arrows, since there is only one other direction for translation.) If you find the perspective distracting when performing this type of translation, you can turn it off in the Camera Parameters dialog box (opened from the Views dialog box), as described in Section  29.5.2.

Rotating the Line Tool

To rotate the line tool, you will click the mouse-probe button on one of the white axes with arrows. When you click on one of these axes, a green ribbon will encircle the other arrowed axis, designating it as the axis of rotation. As you drag the mouse along the circle to rotate the tool, the green circle will become yellow.

Do not click on the red axis to rotate the line tool.

Resizing the Line Tool

If you plan to generate a rake surface, you can resize the line tool to define the length of the rake. Click the mouse-probe button in one of the white rectangles at the ends of the "line'' part of the tool (shown in black in Figure  28.5.2) and drag the mouse to lengthen or shorten the tool. Green arrows will show the direction of stretching/shrinking.

Resetting the Line Tool

If you "lose'' the line tool, or want to reset it for any other reason, you can either click on the Reset button to return the line tool to the default position and start from there, or turn the tool off and reinitialize it as described above. In the default position, the line tool will lie midway along the $x$ and $y$ lengths of the domain, spanning the $z$ domain extent.