in the Tools panel. The cursor changes into .The level/window tool can be used on both 2D and 3D viewers to change the level and window of the values used to convert the data into an image or model. Depending on the type of image the result will differ.
When in the 3D viewer, the level/window tool is used to control the scaling of the transfer function. Widen or narrow the range of values used to generate the patient model.
Using the level/window tool on the 2D viewer will only affect the visualization of the slices, not the patient model. More information about level and window of CT slices can be found in this section.
The level/window action is used to alter the range of values used in the transfer function. By doing so, the visualization of the 3D model can be improved.
Note
The moment the level/window tool is used on the 3D viewer to change the transfer function, a new transfer function is created in the list of transfer functions in the This Patient section. Therefore, it is always possible to revert to the original templates.
To change the range:
1. Click Level/window in the Tools panel. The cursor changes into .
2. Click and hold down the mouse button.
3. Drag the mouse in different directions in the 3D view.
— Drag up or down to move the center of the transfer function without affecting the width of the range.
— Drag left or right over the patient model to respectively widen or narrow the transfer function range.
4. The patient model changes accordingly.
Note
In the case of bone surface rendering, the range of what will be shown is fixed. Therefore, it will be impossible to widen the range. It is, however, possible to move the complete range to a different position in the scale of HU values and opacity (see the Adjust a transfer function section) and thereby change the visualization of the patient model. To do so, drag the cursor up or down.