How do professionals create parts that will be assembled and mate successfully, but be able to change the dimensions of one part and in turn the dimensions of other parts that are below it in the food chain change accordingly? I have acquired some understanding of how to do this within a part using Smart Dimension, but don't know how to do it in an assembly. I also have mixed success trying to create parts 'in context' (within an open assembly) using top-down modeling.

Even as simple a model as nested elliptical cylinders stumps me. Our project is to model the spinal cord and import into a finite element analysis program (COMSOL). We should be able to change the dimension of the central cylinder (the white matter) and let it drive the dimension of the tissues that surround it. But this must be a common situation. Thank you!