Volume Clipping Widget Help

This widget is gotten by picking "Volume Clipping" from the menu you get in the Volume Display widget when you click on "Edit Volume Display". This widget is used to specify which subset (spatially) of the image data to

X, Y, and Z Sliders

Only display the specified subset of the volume data. It is easy to examine single slices by setting two associated sliders to the same value. Thus z slices are examined by setting both z sliders to the same value. The sliders can then be locked together by clicking on the "lock" toggle above the sliders. Sliders can be moved up and down by singe increments by clicking on the arrow keys. If you want to look at single slices, you may want to make them opaque (set both Opacity sliders to 0). If you don't use RGB Play to look at slices, you might want to manually set the correct override mode (set X/Y/Z Override in the Volume Debugging Widget). Note: if you are not displaying in the highest resolution (level 0) then when you single step though data planes you will not see a change for every step (since if you are at resolution 1 every 2 data planes are combined so that you will only see the image change every 2 slices). Set both Res sliders to 0 if this bothers you. Note: The Edit Data Planes widget permits the display of 3 different data slices simulataneously (one X plane, one Y plane, and one Z plane). These can also just be shown as wireframe outlines. In addition one arbitrarily oriented plane can also be specified. See that widget for more details.

Lock Z to Obj

When pushed, this button locks the action of the two Z sliders (described above) to the Object Clipping sliders on the DAVE Master Widget. Thus, if you use the Object Clipping sliders to view only a subset of your object you will see a related subset of the 3D data volume (assuming that the object is oriented so each section of the object is parallel to a z data plane - as most of our objects are). Thus if you have the sliders set to only show a volume subset immediately prior to the object (e.g., Z clipping 0-10 and Object clipping 11-20) then if you move the object sliders (e.g. to 20-30) the Z clipping slider will similarly change (e.g. to 9-19).

Z Clipping Sliders

Sliders for setting front and back z clipping planes. Data in front of the front clipping plane or behind the back clipping plane is not shown. "Front" and "behind" are relative to the screen. In other words, it depends upon the orientation of the volume data set (unlike the X,Y, and Z sliders). This works the same way as the Z-Clipping slider on the DAVE master widget, but only affects image data, just as that slider only affects object data.

Help Button

Show this help message.

Hide Button

Hide volume control panel.

Volume Clipping Menu

Default Values: see description above. RGB Play: see description above. Volume Debugging: Pop up this widget and set the Z override on if you want to see the data only as z-planes. rarely used. Clip Wireframe to Volume: When set, this causes the volume clipping sliders to also clip wireframe objects. See also: -volpad command line option (so that you can still use this clipping when only single z-planes are displayed, without clipping out all the objects). Increase Auto Zclip Step by 1: Set this so that whenever you are not paused, the lower zclip will increment. So if you set the rotation angle to zero and have this set, DAVE will increment through all the zslices (first lock the low and high slices together). This is like playing through the images (may want to set in the image to Opaque Data too). Each time you choose this the z increment increases, so that you will play through quicker (by skipping z planes). Decrease Auto Zclip Step by 1: Decrease the step size by 1 each time this is picked. Once this is back to 0, the check mark in the "Increase Auto Zclip Step by 1" entry will be removed.

NOTE: a 3D box can be displayed about the currently chosen volume subset by picking "V. Sliders" on the Edit 3D-Grid Widget.

Copyright 1995 by Lawrence M. Lifshitz and the University of Massachusetts Medical School. All rights reserved.