I'm creating an injection mold and I'd like a way to easily represent water moving through cooling channels for customers and mechanics to use as a reference. I'm not looking to actually simulate water or create technical recreations or anything, just a simple way to visually show the path water will take.

I have tried using the "Edit Appearance - Faces" feature to "paint" the faces but it always ends up marking more than the specific faces I request. Is there a way to visually show water, or to draw a blue line, or even better to animate this somehow?

I've attached an image to hopefully clarify what I need to represent. Water comes in from the bottom two center fittings and works its way up and outward to return to the bottom outer fittings.

Message was edited by: Chris Everson - clarification