Reusing data in parts and assemblies

The re-use of data is one of those huge time savers that we talk about a lot. Doing things faster is great, of course, but the fastest way to do something is to not do it at all, or to just copy it from something else similar you’ve already done.

If you’re not familiar with Solid Edge, or with the Synchronous Technology component of Solid Edge, you might not have a detailed idea of some of the finer applications of the Synchronous scheme. From reading other articles on this blog, you probably already know that Synchronous Technology is essentially direct edit plus automated feature recognition, which enables you to apply design intent as you need it, and change the design intent when you’re making the changes to the model itself. The design intent really stems from the model faces you select to change, plus any relationships that you want to turn on or off between model faces. This is what replaces putting features in order, and using sketches to drive those features. Dealing with the model directly is more intuitive – just makes more sense. Eliminating the constraints of feature order means that you don’t get handcuffed by dependency.

That may be the long way around describing it, but essentially, Synchronous Technology takes the intelligence out of the model and puts it in the interface. There are a lot of implications of doing that, so let me say it again. Synchronous Technology applies all of the intelligence to the interface, enabling you to change relations and dependencies on the fly, rather than building these relationships into the model indirectly through features, sketches, and feature order.

Because SE doesn’t save the “smarts” with the geometry, it means that we can reuse the data in places where it was never intended to be used. All we need is geometry – similar geometry. You can’t do this with standard history-only feature lists, because the features you want to reuse may not be all right next to one another in the list.

When you’re setting up a library feature in history-only CAD, you have to be very careful about your dependencies – don’t make references to anything outside of the set of features that you’re going to try to reuse as a feature. This is part of the reason that libraries of reusable data are so underused in history CAD. Because it’s difficult, and sometimes impossible to take what you have and reuse it, you almost have to rebuild it with the specific purpose in mind.

For example, take this buckle from a ratchet. The long arm and the short arm are similar in a lot of ways, but not identical. Solid Edge has a set of tools that allow you to quickly copy/replace/rename components in the assembly in ways that make sense. You can:

• replace one part with another part
• replace a part with a library part
• replace an existing part with a new blank part
• replace an existing part with a renamed copy of itself

This particular issue doesn’t have anything to do with Synchronous or history modeling, it’s just about Solid Edge having great tools to help you reuse data.

So for the ratchet buckle, I would make one side of the buckle, then copy it, meaning add another instance/occurrence, and replace the occurrence with a copy with a different name, and start making changes to it. Or you could insert a copy of one part into a new part, break the link, and start making changes.

When I was a history-based wonk, I used to talk about “hack and whack” modeling in a derogatory way. That’s because I felt that you had to have a good reason for every thing you did. You see, in history modeling, it matters how you do things. It’s not just the end result, but how you made the correct end result that matters.

Of course now that I’m older and wiser, and using Synchronous, I realize that academic snobbery really doesn’t help you model great parts or assemblies. All that effort you put into getting the correct process in history modeling is wasted. Your engineering manager doesn’t give you extra points for first making the design process difficult, and then getting your unnecessarily complex method correct. No. You get judged only on the quality of your finished design. So instead of saving time by reusing similar geometry, you are wasting time by making sure your process is correct. For any of you that live with a touch of OCD (obsessive-compulsive disorder), that should sound familiar.