SoTrackballDragger is a ball wrapped in three circular stripes. The stripes are oriented like wheels that spin around the x, y, and z axes. Drag the stripes to rotate the trackball around those axes. You do not have to hit the lines; pick anywhere within the stripe's outline. To rotate the trackball freely in 3 dimensions, click the area between the stripes and then drag. An invisible but pickable sphere initiates this dragging. If the mouse is still moving when you release it, the trackball will continue to spin.

Press the <Control> key to scale the trackball uniformly instead of rotating. This behavior may be disabled by setting the environment variable OIV_DISABLE_DRAGGER_CTRL_KEY to false (see SoPreferences).

Press the <Shift> key and the user axis appears; this is a draggable axis with an extra stripe around it. Moving the mouse along the surface of the sphere drags the 'pole' of the axis. Release the <Shift> key and the user axis remains; drag the new stripe for constrained rotation around the user axis. To make the user axis disappear, press <Shift> and drag the pole to where two of other stripes intersect. This aligns the user axis with a primary axis, at which point the user axis disappears.

As you drag the trackball, it updates its rotation field, or its scaleFactor field if the <Control> key is down. As with all draggers, if you change the fields the dragger moves in response.

Remember: This is not an SoTransform ! . If you want to move other objects with this dragger, you can either:

• Use an SoTrackballManip, which is subclassed from SoTransform. The manipulator creates one of these draggers and uses it as the interface to edit the manipulator's fields. (see the SoTrackballManip reference page).

• Use field-to-field connections to connect the fields of this dragger to those of any SoTransformation node.

You can change the parts in any instance of this dragger using setPart(). The default part geometries are defined as resources for this SoTrackballDragger class. They are detailed in the Dragger Resources section of the online reference page for this class. You can make your program use different default resources for the parts by copying the file $OIVHOME/data/draggerDefaults/trackballDragger.iv into your own directory, editing the file, and then setting the environment variable SO_DRAGGER_DIR to be a path to that directory.

This dragger has both a default and a WYSIWYG version:

Default Dragger	WYSIWYG Dragger

NOTES

Unlike most multi-function draggers, SoTrackballDragger is not a compound dragger made up of other draggers that perform its smaller tasks. This is not because it was inappropriate, but because the trackball was written before implementation of the methods that take care of synchronizing multiple child draggers. The younger SoCenterballDragger is similar in form to the trackball, but the centerball is a compound dragger.

FILE FORMAT/DEFAULT

TrackballDragger {

renderCaching	AUTO
boundingBoxCaching	AUTO
renderCulling	AUTO
pickCulling	AUTO
isActive	false
rotation	0 0 1 0
scaleFactor	1 1 1
callbackList	NULL
surroundScale	NULL
antiSquish	AntiSquish {
	sizing LONGEST_DIAGONAL
	}
rotator	<trackballRotator resource>
rotatorActive	<trackballRotatorActive resource>
XRotator	<trackballXRotator resource>
XRotatorActive	<trackballXRotatorActive resource>
YRotator	<trackballYRotator resource>
YRotatorActive	<trackballYRotatorActive resource>
ZRotator	<trackballZRotator resource>
ZRotatorActive	<trackballZRotatorActive resource>
userAxis	<trackballUserAxis resource>
userAxisActive	<trackballUserAxisActive resource>
userRotator	<trackballUserRotator resource>
userRotatorActive	<trackballUserRotatorActive resource>

}

DRAGGER RESOURCES

Resource:	trackballRotator
Part:	rotator
Appearance:	Invisible but pickable sphere
Description:	Initiates unconstrained 3D rotation. Slightly smaller radius than the stripes, so you must pick between the stripes to use it.
Resource:	trackballRotatorActive
Part:	rotatorActive
Appearance:	Invisible sphere
Description:	Displayed during unconstrained 3D rotation.
Resource:	trackballXRotator
Part:	XRotator
Appearance:	White outline of a stripe aligned with the X axis.
Description:	Pick this to initiate constrained rotation about the X axis.
Resource:	trackballXRotatorActive
Part:	XRotatorActive
Appearance:	Yellow version of the regular XRotator
Description:	Displayed during constrained rotation about the X axis.
Resource:	trackballYRotator
Part:	YRotator
Appearance:	White outline of a stripe aligned with the Y axis.
Description:	Pick this to initiate constrained rotation about the Y axis.
Resource:	trackballYRotatorActive
Part:	YRotatorActive
Appearance:	Yellow version of the regular YRotator
Description:	Displayed during constrained rotation about the Y axis.
Resource:	trackballZRotator
Part:	ZRotator
Appearance:	White outline of a stripe aligned with the Z axis.
Description:	Pick this to initiate constrained rotation about the Z axis.
Resource:	trackballZRotatorActive
Part:	ZRotatorActive
Appearance:	Yellow version of the regular ZRotator
Description:	Displayed during constrained rotation about the Z axis.
Resource:	trackballUserAxis
Part:	userAxis
Appearance:	Thin purple line
Description:	Displays the user axis. Dragging the userRotator rotates about this line.
Resource:	trackballUserAxisActive
Part:	userAxisActive
Appearance:	Thin purple line
Description:	Displays the user axis. Dragging the userRotator rotates about this line.
Resource:	trackballUserRotator
Part:	userRotator
Appearance:	Transparent green stripe circling the user axis.
Description:	Pick to initiate constrained rotation about the user axis.
Resource:	trackballUserRotatorActive
Part:	userRotatorActive
Appearance:	Brighter green version of the regular userRotator
Description:	Displayed during constrained rotation about the user axis.

CATALOG PARTS

All Parts

Part Name	Part Type	Default Type	NULL Default
callbackList	NodeKitListPart		yes
surroundScale	SurroundScale		yes
antiSquish	AntiSquish		no
rotator	Separator		yes
rotatorActive	Separator		yes
XRotator	Separator		yes
XRotatorActive	Separator		yes
YRotator	Separator		yes
YRotatorActive	Separator		yes
ZRotator	Separator		yes
ZRotatorActive	Separator		yes
userAxis	Separator		yes
userAxisActive	Separator		yes
userRotator	Separator		yes
userRotatorActive	Separator		yes

Extra Information for List Parts from Above Table

Part Name	Container Type	Possible Types
callbackList	Separator	Callback, EventCallback

Reference