Releasing Streamlines from Centroids of Elements

imgoutA request came in the other day to release streamlines from the centroids of all of the 2D elements of the selected parts. Now, EnSight, the default seed locations are from the nodes of the parts, not the centroids. However, this user would like to release from the centroids of the parts selected.

Python to rescue. We can utilize the Calculator Capability in EnSight to compute the X,Y,Z coordinates of the selected parts, and use the “NodeToElem” to convert those three scalar variable field values to be at the centroids of each element. With Elemental Values at the centroids of the parts, we use the FlatFile export with the “CELLID” parameter and ascii format to write out the elements of selected part(s) and their elemental variables to a text file. We can then just reformat this text file into a qualified “Particle Emitter File”. Voila. Within the standard streamline creation of EnSight, we can use a “Particle Emitter File” as the seed locations for the Streamlines, and therefore generate streamlines from the centroids of all elements in the selected part(s).

See below a short little Python Code to do this operation, as well as an image of what such a release would look like.

Python Utility to create Particle Emitter File from Centroids of Parts Selected