In today’s post, I would like to focus on Functional Modeling.
I’ve always wondered why this workbench never really caught on. Speaking purely from an FM1 trigram standpoint, it comes with the MCE add-on that most people who have PLM Express have added on to their CAC (CAC+MCE).
FM1 gets you the Functional Modeling Part Workbench.
First let’s talk about what it was created for, which is plastic parts or parts with draft, because it could also be used for core-cavity type parts like castings. This workbench is very unique in that you do not necessarily model in a particular sequence order like you would in the Part Design workbench. Modeling in the Part Design workbench is what we would call traditional feature modeling, i.e. create a sketch then make a pad, then add some dress up features like draft, fillets, then shell it out, etc.
There is nothing at all wrong with modeling this way – in fact, it is how most of this work is done today! Now let’s look at what we call Functional modeling which looks at a shape and incorporates a behavior for a specific requirement. Think of it as a Pad (Feature) plus a behavior. For instance, in the Functional Features you would find items like Boss, Rib, etc.
It’s a new philosophy because, as these are really considered defining specifications, it really does not matter what order they are built in – giving you major flexibility; in fact, you can begin the design with these before you have built a main shape. Essentially, the solid is made up of a bunch of Basic Features (generic shapes) and Functional Features (specific shapes) and consequently the resulting geometry is always the same.
It’s very important to note that the final solid will be fully compatible with ANY CATIA workbench. You can easily reuse the bodies to quickly modify the parts for detailed design, use them in catalogs, etc.
As a designer you are focusing on the shapes based on manufacturing processes, which works out great, because you are kind of making sure mentally that it is manufactured right the first time, and typically the specification tree ends up being a whole lot shorter, so design changes are quick as well. When modeling in the workbench, you are always focusing on your design intent, because each time you build a feature it’s going to prompt you to consider things like Wall Thickness, Parting elements, Pull direction, etc.
Let’s look at a simple part done in traditional modeling methods. There are two bodies with about five features each, and you have to rely on a Union Trim between the bodies in order for it to come come out correctly. Union Trim is nice, but it also relies on B-REP (face) geometry, which will tend to fail every time a major change is made to the main body. That’s essentially 10 features and a B-REP to deal with.
Now let’s look at the same part modeled in FMP.
There are five features total, and that includes the shell, which is built automatically when you access the Shellable Prism feature and the plane (not taken into above count) used for the top of the rib definition – and I added in an edge fillet to fillet the ribs to the main shape. Ask yourself: which one of these can I make changes to faster? Why is that? The shellable prism dialog allowed me to include the draft, lateral, and bottom radius in the initial creation and therefore will be available in the edits as well.
The ribs did not have to be developed and then drafted and then patterned, as I only had to make one sketch with a line for each rib and then used the Rib functional feature. It was already smart enough to go only to the internal shell by default, and its thickness was read from the shell properties (first feature in tree). But wait! There’s more. The draft and filleting was also available here.
Cool, eh? Tie this stuff to some simple parameters…and now you are really cooking with oil! So again I wonder: why this isn’t being incorporated, or never got too popular? Is it fear of a big change? Maybe it’s a training thing? If that’s is what is holding you up, we have you covered. We can teach you this workbench in one day of training. One day!
Bottom line: What are you waiting for? How can we help you achieve your CATIA dreams and goals?
Until the next time…
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