AutoCAD 2D (also Draftsight) has a feature called "Stretch" that still beats 3D Software companies because it helps users to modify assemblies easily for the benefits below:

     1. Assembly drawings can be sent to prospects for quotation purposes very fast

     2. Modifcation of Assembly can be done easily to complete a similar project

     3. It helps customers for who start designing from top to bottom (from assembly to part)

Why not invent a plane which touches parts to strech in 3D? I am sure it will acquire many new companies trusting in my 2D and 3D design experience for 5 years!