Object Clipping Widget Help

Object Clipping

Objects always have one unique dimension, which is usually the z-dimension. This is because the pts files which specify the objects are composed of outlines each of which has a constant z, or because the z-dimension is really a time dimension for a 2 dimensional time series. The Object Clipping slider controls which subset of an object (along this dimension) will be displayed. The number above the sliders refer to the z coordinate specified by the slider below it. The left slider should always stay less than or equal to the right slider. The arrow buttons to the side of the sliders can move the sliders in unit z increments (the double arrow sliders) or in sub-unit increments (the single arrows - typically only useful for debugging bifurcations in an object). The z-dimension is defined when the data is read in and does not change depending upon the orientation of the object in the scene. Note: All displayed objects are clipped based upon the current setting of the Object Clipping slider. Thus all objects are clipped identically and regardless of whether they are displayed as surfaces or wireframe outlines. Volume data is not affected by the Object Clipping sliders.


Z-Clipping cuts away (ie, doesn't display) the nearest (left slider) and furthest (right slider) parts of the objects. The larger the value of the left slider the further away a part of an object can be and still be considered near enough to be cut away. Similarly, the smaller the value of the right slider the closer an part of an object can be and still be considered far enough away to be cut away. Ie, anything in front of the left slider clipping plane or behind the right slider clipping plane will not be displayed. Z-Clipping affects all objects identically and does not affect volume data. "Near" and "far" are relative to the screen of the workstation and hence as the objects rotate different parts of them may be clipped away.


Clicking on this button locks the two object clipping sliders together so that moving one causes the other to move also. Thus a constant separation is maintained. The object clipping sliders can also be locked to the volume clipping sliders, see the Volume Clipping widget (gotten from the menu on the Edit Volume Widget).
Copyright 1995 by Lawrence M. Lifshitz and the University of Massachusetts Medical School. All rights reserved.