Displaying buildable area as an overlay on terrain

Hi, I'm a member of a small team working on a fairly simple project.

One issue we're having is that we want buildings to be placeable only on flat terrain and only if they are within range of a power source. The issue is not the placement, but rather we would like to give the player a visual cue as to which areas are available to be built upon (such as a green highlight on the ground or something similar.)

We've thrown around ideas such as creating a texture that matches the shape of the buildable area and using a projector to show that on the ground, then setting up another projector on each power source projecting another color, and the areas where they combine are the areas which can be built upon, but this seems like it would be a very messy way of doing this.

We also thought about the standard red/green silhouette but decided that the image of that didn't fit well into our concept.

So my real question: does anyone have any experience doing this kind of thing? Any suggestions on how to approach the problem? Any thoughts at all?

Any assistance would be appreciated, and I thank you in advance for taking the time to read this.