It sounds like some of you are still confused. Some people are asking me to compare SolidWorks Move Face to the Solid Edge Synchronous Technology method for making edits. I know that the interfaces for the methods look similar, but these are not the same tools. I suppose if you’re a salesman, and you have to say that SW has equivalent functionality, that would be one place where you might expect to hear someone say that these tools are essentially the same. But they’re not, and here’s why.
Let’s keep looking at the punch holder model because it’s not a bad one.
You would think that any comparison that allowed one software to operate with native data while another is forced to use imported data would be patently unfair. And it is. In this case, it’s very unfair to make SW use its own native data and to allow SE to use the SW file imported directly into SE. Why is that? Because for geometry like the punch holder, history serves no purpose. Well, you could take the existential route and argue that material must exist before it can be cut, but there is nothing that says you have to have separate features, you could just extrude a single sketch, and the sketch doesn’t care about history. Or you could extrude the holes as positive, and then subtract them from a block created later. So order doesn’t matter.
There are times when you need to make one feature first, and then a feature that has some dependency to the first feature. Yes, I do believe that history modeling is not dead. It is just grossly misapplied in some cases, including the case of making a prismatic punch holder part as a history-based part. But this is exactly the kind of part that a lot of machine design is involved with.
So because this is not a great part to make a poster child for history-based advantages, some people are arguing that you should use a method that looks like direct editing. Use Move Face instead of editing the original sketch. Would you do this in real life? Some time ago I wrote about using sleazy CAD tricks to just get the job done sometimes. Move Face is clearly a sleazy CAD trick. Sometimes you do it. But it’s sleazy.
The problem with trying to make a history modeler work like a direct modeler is that you’re still making history-based features. So you are actually adding to your original problem. You’re putting an infected band-aid over a wound. Sure it stops the immediate bleeding, but there is a price to pay later on. Let’s take a look.
In this image, you can see that the Move Face feature is added at the bottom of the tree, and that it adds another 20 seconds of rebuild time. This was using Move Face to edit the length of the plate by 1″. And this is in addition to the time it takes to make the feature, which you have to sit and wait for the preview to show, and all.
But what if you wanted to also edit the width by 1″? Or what if you wanted that change to be symmetrical? The answer is that you would have to add another feature, which would add another 20 seconds or so to the rebuild. This isn’t any good. In fact, it’s pretty bad. You’re just making matters worse than they already were.
I’d make a video of this, but it would be long and boring. You can simulate it by staring at your monitor for a couple of minutes doing nothing.
What happens in SE? It takes about 20 seconds to do the edit. And it doesn’t add a feature to the tree. The next time you have to make the same or different edit, it takes about the same amount of time. Edits are not remembered, so the times to create them don’t get compounded.
Plus, you have some additional options, like the Tip, Lift and Extend options we looked at a couple of posts ago. SolidWorks Move Face just works with the existing BREP faces. It may extend or trim or even delete them, but it will not change the faces adjacent to the selection set. Here’s a movie of a simplified case:
And then there’s live rules. Live Rules is really a method for selecting faces according to certain geometrical rules. Using different rules for selecting faces in different situations enables you to change the design intent without editing features. If you’re still struggling with the whole concept of Synchronous Technology, this is one of the key concepts. Features, faces, selections, and moving faces according to rules. And it works with imported geometry, although there are some advantages to native features. Best practice is a thing of the past. It doesn’t matter how you make something, as long as the geometry is correct, that’s all that matters.
Alright? So I can forgive a bunch of you for wanting to compare SW Move Face to SE Synch Tech, some of you even going as far as to say that the comparison was “apples to apples”. Apples to apples to me is to use the preferred method for each modeler. There is no question that continuing to use Move Face in SW to cover up problems with history is really making the problem much worse. I’ll remodel the part in SE ordered just for comparison in the next day or two.