Creo with Windchill is lacking function with Creo 3.0 and later to allow the comparison and the redefine of 3D geometry of different revisions of the same part. (It is written in CS202061 as 'With Creo 3.0 cannot have multiple sessions connected to the same cache and use different primary servers/active workspaces.' )
However Creo 2.0 was able to do that because Cache sharing between multiple Creo sessions is supported . So, users were able to see and compare two revisions of the same model from each different workspace (It is written in CS131176 )
Although additional another Creo licenses are needed to do that, it was very useful function and customers were utilizing this function on Creo 2.0. To design new model, the designer would like to refer to the previous model by seeing it. And, the designer hopes to use the redefine menu to check how the previous model was created.
Hence, Designers are very struggling with it because customers can no longer utilize this function from Creo 3.0. So, customers hope to be restored this function.