In this post I am going to try and explain the Change Manager which is the heart of the “Fusion” in Inventor Fusion TP2. As it stands, Inventor Fusion is delivered as two parts (1) the Inventor Fusion standalone application; and (2) an add-in to Inventor 2010 called Change Manager. When the time comes, Autodesk will merge these two into a single application, but for now users need to work in two modeling environments.
In short, the Change Manager does the almost impossible task of inferring the parametric changes that resulted from direct modeling operations. Something like recreating a bunch of fruits from a fruit salad. Obviously, the more you mess around with a model using direct modeling in Inventor Fusion, the more difficult the problem is going to get for the Change Manager in Inventor 2010.
The Change Manager compares the changes in a model with the original model and makes an attempt to infer the change in parameters, sketches, constraints, etc. that will need to be made to have the same result as that achieved through direct modeling. As a simple example, if you have an extrude feature in an Inventor 2010 part and you pull the extruded face further in Inventor Fusion so as to increase the original extrusion distance, the Change Manager computes the change in the extrusion distance and accordingly edits the extrude feature in the Inventor 2010 part so as to reflect the change made using direct modeling in Inventor Fusion. This may sound like an easy thing to do for simple features like extrudes, but as you can imagine, things can get complicated pretty quickly for complex features. More so when a bunch of features depend upon each other for their existence. Moreover, in history based feature modeling, there can be more than one way to do arrive at the same result, and each one of these methods can affect other features further down the feature tree. So how does the Change Manager solve all these problems?
The Change Manager takes each direct modeling operation as an independent change and comes up with a list of possible “treatments” that can be used to effect that particular change in the original history based feature tree. Each of these treatments is given a fidelity factor, depending upon its probability of being the right treatment for the job. These treatments are then sorted according to fidelity and the one with the highest fidelity is set as the default.
Once the treatments for individual changes are determined, the changes are then analyzed for dependency on each other. Changes which depend on others are given a higher weight and drop down the list. After all is said and done the Change Manager window looks something like the following image. As you can see the items in the Change column tell you what was changed in Inventor Fusion. Each item in the Treatment column is actually a drop down list which can have more than one option, with the default being the one with the highest fidelity.
I asked Kevin whether they could show the changes in a tree fashion instead of a flat list. This would give the user a good idea of which changes depend upon others. He said that it was possible since they already had the hierarchy structure of the changes. So you can expect the Change Manager to look a bit different in the next release.
The third Ignore column is very interesting. Since the Change Manager treats each change independently, the user can choose to accept or reject each change independently as well. This means that if you delete a hole in Inventor Fusion or change its diameter, and for whatever reason, if you want to retain the original hole when you get the model back into Inventor 2010, all you need to do is simply check the Ignore box for that change in the Change Manager and you will have your old hole back. This means that you can actuall hand over your history based parametric model to someone who can thrash it around and you still have complete control of which changes you wish to accept and which to ignore. I feel this is an extremely powerful feature and something that will go down well with hardcore proponents of history based parametric modeling.
You can apply one treatment at a time by selecting the change in the list and clicking the Apply Treatment button or you can simply go ahead and click the Apply All button to let the Change Manager apply all the treatments at one go. According to Kevin, most users will not have to bother themselves with applying individual changes, unless they need the Change Manager to behave differently. “Normally, the Apply All button will do the trick just fine“, he said.
I asked Kevin whether the Change Manager was smart enough to handle any change made to any feature by a Direct Modeling operation in Inventor Fusion. He replied:
In its present state, the Change Manager can handle extrudes, holes, fillets, chamfers and patterns. We still need to tackle the revolve and sweep features, which we hope to in a future release. A lot of work has been done and a lot needs to be done. At this point in time, we are quite excited at what we have accomplished. But we are more interested in getting this technology in the hands of customers, see how they use it and get their feedback.
I have downloaded Inventor Fusion TP2 but the Change Manager add-in needs a Subcription Release of Inventor 2010. I have a different version of Inventor 2010. So I have not yet tried the Change Manager part of the software. I gathered all of this information from my conversation with Kevin last night. So it is quite possible that I may have caught the bull by the tail in some cases.
I hope to analyze the innards of this technology once I get to lay my claws on it. As you most probably know by now peeking under skirts is something that I throughly enjoy. 😉