CFD Online Discussion Forums - Using a variable to set a plane

Hello,

I've been trying to mess around with my domain for analysis purposes. Currently, I am taking integrals and sums across my entire domain, but really need to be able to isolate the region down to some box around say a fluid interface.

I've been trying to do something like:
1. Create an iso-surface based on a 5% contour
2. Use the calculated to turn the coordinates of said iso-surface into a variable
3. Find the max and min x,y coordinates of the iso-surface
4a. Using filter, I want to remove any region on the master part greater than the max's and less than the minimums.

- or -
4b. I select the master part, then using calculator create some variables which are slaved to the master part and are equal to my iso-surface max and min values.
5. I try 4a. as listed above, to remove any region greater than the max's and less than the mins.

However, following either procedure, ensight crashes without any warning or reasoning. I am unsure of why - any advice on how to do this would be useful.

In fact, trying to filter using any variable as opposed to a number crashes ensight regardless.

As mentioned before, I'd rather use a plane tool, since I'm not even sure if filter will actually allow me calculate the regions only within the box. But- as far as I can see, plane tool does not allow one to use variables and instead needs direct input from the user. Since my fluid interface moves through time, it would be nice to have something do this automatically so I can take the integral/sum using a constant area around the interface.