Negative Cell Volumes

ParaView Support
1

Hello. I am using Paraview 5.5.2 and I am looking for some advice on how to filter out cells with negative volumes.

I discovered that some cells had negative volumes when using the Integrate Variables filter on a positive quantity and received a negative result.

My filter chain is the following:
[input data]
CellSize Filter
Threshold Filter -> Volume -> minimum 0.

The problem that I am encountering is that the resulting selection does not look correct. In fact, it looks like it is keying off of a different scalar value in the dataset than volume.

I renamed the volume array output of the CellSize filter to a new name and set the Threshold filter to key off of that new name just in case that was the issue, but I got the same result.

Clearly I am missing something. Is there a better way to eliminate negative volume cells? Is there a quick diagnostic that can be used to determine if negative volume cells exist?

Thank you in advance for your help,
-A

2

From your description, it sounds like you are doing things right. Could it be that perhaps cells that you feel should have a positive volume the CellSize filter thinks is inverted and therefore a negative volume?

Here is something you can try. Open the Find Data dialog box and do a query finding cells with the volume less that 0 (instead of using the Threshold filter. This is two totally different code paths to find the same data. Do the selected cells match those the Threshold filter is removing?

When you select data with the Find Data dialog box, you get a spreadsheet to inspect the selected data. Does the data selected make sense with your selection?

Those actions won’t solve your problem, but will hopefully help you diagnose what is going on.