Q. How do I visualize data with "holes" in it?

A: I have used the following to visualize data with holes in AVS:

1. Set missing values to something well out of range of actual data
2. Use some form of field reader
3. Use field to ucd
4. Use ucd threshold to throw out all cells with out of range values
5. Then use ucd iso, ucd contour, ucd slice, etc.--producing pictures with holes.

Note, field to ucd needs 3D fields.

You may also use the carpet module at the IAC (turn on "leave holes").