Cube measuring Tool

What Feature would you like to see included within TaleSpire?
What does it look like, how does it work, how is it used. Paint us a figurative picture.
I would like a measuring tool to feature a cube, as it is something that a lot of spells in D&D use. Such as Faerie Fire.

What situations would this Feature be useful?
Descriptions, examples, interactions with existing features - whatever you can think of to get your idea across!

 This would mostly be useful for figuring out the radius of spells far easier, I am unaware how hard it would be to implement, but it would be very useful. Mind you this would be a three dimensional cube, that, since it is a cube, you only need to measure out two facets of it, as the height of the cube can be found from the length of two sides, even one side.

Additional Thoughts/Details