Rotate XYZ

The orientation of an object is set by the rotation of its centre. The RotXYZ command, available in all modules except Tools, lets you rotate points or objects interactively with the mouse or numerically with a dialogue box (see Changing Values). All possible orientations can be set with a combination of three angles of rotation: x-axis, y-axis, and z-axis. Objects rotate around their centres (local), but rotate differently on the axis depending on the rotation mode defined (LCL, GBL, ADD, REF, and PLN - see Rotation Modes). Points rotate around the global centre (origin).

Rotating an Object

1. Select it and choose the entire RotXYZ menu cell collection or one of its axis cells (x, y, z).
2. Select one of the Rotation modes (see Rotation Modes).
3. Choose a way to change the rotation values for the object as described in Changing Values.

Rotating Points

1. Select an object and choose Show->Point to display its points.
2. Activate the tagged point mode by selecting the TAG manipulation mode (see the Manipulation Modes section).
3. Tag the points you want to rotate (press the t Supra key or refer to the Tag commands).
4. Choose the entire RotXYZ menu cell collection or one of its axis cells (x, y, z).
5. Choose a way to change the rotation values for the points as described in Changing Values.
   

Note:

Note that transformations on points are additive only; clicking Set in the Rotation dialogue box has the same effect as Add.

Changing Values

You can change the values in the Rotation menu cells using the mouse or the keyboard:

Using the Mouse

• Choose one of the three individual axis cells (RotX, RotY, or RotZ) for a transformation to affect only that axis. This configures the mouse buttons so that when you drag the object or points, the:
  
  • Left mouse button applies a small increment on that axis.
  • Middle mouse button applies a medium increment.
  • Right mouse button applies a large increment.
    
• Click at the right edge (light grey area) of the Rotation menu cells to activate the transformation for all three axes. This configures the mouse so that when you drag the object or points, the:
  
  • Left mouse button controls rotations in x.
  • Middle mouse button controls rotations in y.
  • Right mouse button controls rotations in z.

The mouse buttons can be used individually or simultaneously.

Using the Keyboard

• Choose one of the three axis menu cells and directly change the numbers in the text boxes in the menu cell. Doing this has the same effect as when you click Set in the Rotation dialogue box (described next).
• Click in the triangular tab in the upper-left corner of one of the axis menu cells to display the Rotation dialogue box in which you can set transformations numerically.

Type the value in the corresponding text box and then click either Add or Set:

• Add increases or decreases the rotation by the value in the X, Y, Z text boxes. For example, if the default for X is 1, you change the value to 2 and click Add, 2 is added to the value of 1 so that the result is 3.
• Set sets the rotation to the value you specify in the X, Y, Z text boxes.

You can also use negative values, which are added or set accordingly.

Math Operations

The text boxes in the RotXYZ menu cells allow you to use the four basic math operations (addition, subtraction, multiplication, and division).

If you have the Multi menu cell selected, the math operation is added to each object's current values, which has the same effect as when you click Add in the Rotation dialogue box. For example, if two objects are selected (one with a rotation value of 45, the other with 90), the number in the Rotation text box is displayed with a "d" at the beginning to show that the values for the two objects are different. If you add +45 to the end of the menu cell's value, the first model changes to 90 and the second to 135. This is different than if you specify 90 in the Rotation text box, which would make both objects have a rotation of 90 degrees.

Note:

If you delete the number currently displayed and replace it with another, all objects are set to that value.

Rotation Modes

There are five rotation modes: Local Axis (LCL), Global Axis (GBL), Additive (ADD), Reference (REF), and Plane of View (PLN). All of these can be used in conjunction with the OBJ, TAG, and CTR manipulation modes (see the Manipulation Modes section).

Note:

By default, the Preferences->Continuous Rotation command is activated, meaning that rotation numerical values are "additive" and do not loop from -180 to 180 degrees, but continue to increase or decrease as the object is rotated (as in the ADD mode). When the LCL, GBL, REF, or PLN rotation modes are in use and you want numerical values to loop from -180 to 180 degrees, simply deactivate the Preferences->Continuous Rotation command.

LCL

Local Axis Rotation mode allows you to rotate an object or its tagged points about its local axis; that is, according to the object's own centre orientation.

The left mouse button rotates about the x-axis, the middle mouse button rotates about the y-axis, and the right mouse button rotates about the z-axis.

This mode and the GBL (Global) mode have limitations: for example, you can't create an animation of an object spinning without creating numerous keyframes.

GBL

Global Axis mode allows you to rotate an object about its centre according to the global axes, no matter how the object is oriented. Tagged points rotate about the global axes.

The left mouse button rotates about the x-axis, the middle mouse button rotates about the y-axis, and the right mouse button rotates about the z-axis.

ADD

Additive mode is activated by default. It allows you to rotate an object about its own centre orientation in the x-axis. In the z-axis, the object rotates about the z-axis of a parent or, if there is no parent, about the global z-axis. Tagged points rotate about their local axes. With this mode, you can animate an object spinning with only two keyframes.

In the ADD mode only, the numerical values are always "additive" meaning that they do not loop from -180 to 180 degrees; the rotation is continued in one direction (positive or negative).

The left mouse button rotates about the x-axis, the middle mouse button rotates about the y-axis, and the right mouse button rotates about the z-axis.

REF

Reference mode lets you rotate an object according to the axis orientation of another object (a reference object). Select REF to activate the Reference mode and pick a reference object according to the mouse button instructions displayed in the status bar. The Reference mode causes the axes of a reference object to represent the global axes, so an object rotates about its centre according to the global axes orientation of the reference object.

Tagged points rotate about the axis orientation of the reference object.

The left mouse button rotates about the x-axis, the middle mouse button rotates about the y-axis, and the right mouse button rotates about the z-axis.

PLN

Plane of View mode lets you rotate an object about its centre according to the plane of view of the window. The plane of view axis is the one that appears to extend out from a window: for example, in the Top window, the plane of view is the xz plane and the y-axis is the axis extending from the plane. If you select the PLN mode, then rotate your object in the Top window, the object would rotate in y using its own centre as the orientation. In the other windows, the object would rotate on the axis extending from their respective working planes.

Tagged points rotate about the plane of view of the windows.

Any mouse button can be used to rotate in this mode.

Last updated 02-apr-1998