If certain basic conditions are met when you start the process to create a new constrained streamline part or edit an existing one, a new in-place dialog will be placed near the visualization display to allow definition of the derived part.

Click the Input Parts button to select the input part(s) that you want to be included in the streamlines.
From the Seed Mode drop-down list, select one of three available types of seeds:
The Snap To Part option, disabled in the screenshot above, becomes available when a tool is in use. When you activate this option by ticking its checkbox, the adjacent drop-down list allows you to select a part along which you can fix the derived part`s location.
The units used in the dialog are in the default SI system and cannot be changed. Coordinates are relative to the laboratory (Cartesian) coordinate system, which also cannot be changed.
The Display group box, arrow button (
), and Create and Close buttons are common functions described elsewhere.