Hi Haz, yes that's correct MoI doesn't have a method of adjusting things like chamfers after you place them. If you think you will want to change those it's a good idea to save off a version of your object before doing the chamfer so you can do a new one.
There are many other CAD programs that do what you are describing, they are called "feature based parametric solid modelers. If adjusting parameter like that is important for you then one of those programs such as SolidWorks, Alibre, Solid Edge, OnShape, etc... would probably work better for you than MoI. The focus in MoI is on making it quick and easy to do simple objects.
I would like to add functionality like that into MoI in the future but it's a big area of work so I don't know when that will happen.
I use one or more of the methods below, depending on the complexity of the model:
Save a new version at regular time intervals so I can go back in "history" and retrieve an earlier version of the object(s). You can open two instances of MoI and copy/paste objects between them.
Copy an object before performing fillets and booleans and move it off to the side for safe keeping.
Copy an object before performing fillets and booleans, assign a unique Style (color), then hide it. Easy to bring it back at any time and it will be in the same position.
