Create size indicators inside scene in Three.js

I'm working on a small 3D wardrobe studio and I'd like to add size indicators into it, so theoretically, I'd loop all the children I want the indicators between and display the number along with an arrow.

Unfortunately, I'm not sure how would I render the arrows and the numbers. Also, I was looking for an already existing solution, but couldn't find any.

My question is, how would I render the arrows between child elements? Are those vectors? It seems like a lot of work to do, do you know any existing solutions? Thank you in advance.

Size indicators don't need to look exactly like those in the picture, it's just for the problem visualization

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