It can be a difficult task to figure out. There is no way to scale a column globally so that the proportions of your beautiful column are preserved (wishlist item alert) but we can show you how to build simpler columns that stretch properly.
The example below is an adjustable column with adjustable base.
First thing you need to setup are reference planes. We have the given Ref Level and we've created a Top of Base and Top of Capital. Remember to goto the plane's properties and give each plane a unique name (we will use this later). Dimension these planes and attach your parameters (as shown below).
Second you have to create each of your elements for base and capital. Now the trick is that after you've created your elements you have to Edit the work plane of each element so that the elements are attached to the reference plane you would like them to "travel with." when adjusting the height parameters.
Now load your column into a project and place it on the 1st and 2nd floors to make sure that the elements are correctly placed and stretch properly in both scenarios.