Not quite that detailed but along those lines. Usually it's simpler like resize a dimension based on another shape that is supposed to be in a fixed location.

Not quite that detailed but along those lines. Usually it's simpler like resize a dimension based on another shape that is supposed to be in a fixed location. Vectors should snap and/or resize to other vectors based on midpoint, center, tangent, concentric, etc. Other times there is constraint based solving going on. And other times there are simple formulae based on the dimensions of other vectors (think spreadsheet style reactive).