Programming with 3D Volume Slabs

The 3D volume slab is a special implementation of clipping planes. It can be used from any of its six boundary box planes to "cut away" superficial structures to allow visualization of anatomic structures and pathologic conditions within the volume.

In LEADTOOLS, the slab option can be applied to all supported volume types except the 3D MPR volume. You can enable the 3D volume slab option by setting the Medical3DObject.Slab.Enabled property after an instance of the Medical3DObject class has been created and the 3D volume has been generated. Setting this property will display a blue rectangular prism outlining the slab boundaries in the volume.

To simplify the slab manipulation for the user, LEADTOOLS assumes normalized planes for each X, Y and Z axis where each axis is represented with a value range of 2 (+1 ~-1). The following properties of the Medical3DSlab class can be used to set the clipping planes to generate the slab:

• X1 Property - represents the first boundary of the slab in the x-axis.
• X2 Property - represents the second boundary of the slab in the x-axis
• Y1 property - represents the first boundary of the slab in the Y-axis
• Y2 Property - represents the second boundary of the slab in the Y-axis
• Z1 Property - represents the first boundary of the slab in the Z-axis
• Z2 Property - represents the second boundary of the slab in the Z-axis

As an example, setting X1 = 0.0f will clip all of the left half side of the X-axis and setting the X2 property to 0.5f will clip half of right side of the X-axis. The same principle also applies to Y and Z axis.

LEADTOOLS also provides interactive slab manipulation from 2D orthogonal MPR planes, when integrated with the LEADTOOLS Medical Viewer via the MedicalViewerMPRCell class. For more information, refer to Programming With MPR Slices. Enabling the slab feature using the Medical3DObject.Slab.Enabled property will display slab boundaries as a rectangle with dotted green lines on each of the 2D MPR (axial, sagittal, and coronal) planes. As an example, the upper and lower rectangle lines refer to Z1 and Z2 properties and the left and right lines refer to the Y1 and Y2 properties in the MedicalViewerMPRCell representing generated 2D coronal (x-axis plane) stack.

You can adjust the clipping planes by selecting the dotted line with left mouse button and moving the mouse. Also, a white grab handle is provided on the top right hand side of the rectangle representing slab boundaries to drag the rectangle. This feature can be used to interactively "cut away" objects that are obstructing the view such as removing the abdominal wall. Please note that enabling slab option will disable all active clipping planes after saving their parameters and which can be reinstated using Medical3DSlab.Reset method.