History AND Direct?

I assume I’m talking to all the smart kids in class. Just because you’re engineers and designers, well, all that math and science weeded out the rest, right? And of course I assume that as the smart kids in class, we all watch the Big Bang Theory, and can relate to the problems of nerds. Sheldon, Leonard, Howard, Raj, Amy and Bernadette each provides something for us to relate to. Sometimes in a “yeah, that happens to me all the time” sort of way, and sometimes in a “don’t you hate when that happens” way.

I might have been at the tail end of the smart kids list, but I was certainly a nerd, and I probably relate best to Leonard. Didn’t you hate it when you did the homework for one of the popular kids in class, and he/she got an A and took all the credit? Sounds like a problem Leonard would have. That used to burn me up. Why the smart kids can’t understand the mistrustful side of human nature is another mystery for a different blog.

Alright, well, how do you relate this to CAD? The big, popular, history-only CAD systems have been telling everybody “yeah, I can do that” when direct editing became “a thing” again. Recently I heard a fresh-faced startup claim the same thing. And some of you have been fooled. In fact, I was fooled for a while. But they’re wrong, they can’t “do that”, even if it looks like they do. Here’s the scenario:

I’ve spent a fair bit of time laying out the real benefits of Synchronous Technology, which is direct editing with a lot of really smart feature recognition, design intent enablement, and flexibility built in, so I won’t make that case again here. What I want to tackle here is the idea that these other systems can even do simple direct editing. The truth is they can’t. They tell you they can, and that Sync Tech is just direct editing, but they can’t and it’s not.

Instant 3D Is NOT Direct Modeling

notdirectmodeling1You might hear the argument that a function called Instant 3D is really just the same thing as Sync Tech and the Steering Wheel. It’s not. It’s just a lame ploy for attention. Here’s why.

This image to the right shows the arrow you get with the Instant 3D function. All it does is change the dimension in the associated sketch, it’s not driving the model “directly”. You have the same capabilities and limitations as you do when you have to roll back the model and edit parent/child features.

In fact, unless you know where the secret switch is, you can’t make the edit shown above at all. The secret switch allows the arrow to drive the dimension, but it also allows other changes to drive sketch dimensions automatically.

notdirecteditTo the right is the Solid Edge Sync Tech direct edit method. The dimensions are connected directly to the model, and the arrow allows you to edit the dimension. The lock symbol in the dimension box will prevent the arrow from changing the dimension, and the green arrows under the dimension box show in which direction the dimension will change if you use the dimension box. I should note that the dimension box was edited into this image. You can’t get the Steering Wheel and the dimension box at the same time. A locked dimension is red, unlocked blue, selected green.

Delete/Move Face Is NOT Direct Modeling

The folks from the big popular CAD program are a bit desperate to look like they have direct modeling so they can just discount it, say it’s not a big deal. So they just tell people that they have it, even though they don’t. They demonstrate something lame, and say “That’s all it is, it’s nothing to worry about, you don’t need it”. Well, they’re half right. What they demo is lame and something you don’t need. But they aren’t demoing Sync Tech.

0024Here’s how this feature ‘Works… It adds a history-based feature. That means that later features may become dependent upon this feature. It means that the feature may fail if you change something the new feature depends on. Most ‘Works users are a little terrified of untangling parent/child relations, and for good reason – they can be convoluted, and there are no good tools to help you. Parent/Child failures can force you into rebuilding all or part of your model.

You know those people who get so fed up with their failed features that they Parasolid a part out, then back in? Those people are secretly craving the kind of editing power you get with Sync Tech from day 1 – without violating all the best practice rules you ever learned.

Move Face is the real clincher, though. 0025First, notice that it does exactly the same thing that Delete Face does in ‘Works. It adds features. And it adds a new feature every time you move a face, even if you move one face, and then move it back. This is actually different from Instant 3D. Instant 3D changes dimensions, but Move Face actually adds a feature to move a face. So it’s the worst of history-based functionality (another history-based parent/child feature) without actually becoming a direct edit function.

Plus, Move Face will simply not work if there are any fillets or other tangent faces around the selected face.

In Sync Tech, we don’t have a fancy name for moving a face, it’s just how we edit the model. Fillets are handled intelligently, because they aren’t order-dependent features, they are just geometry.


So the answer to if ‘Works does history modeling AND direct modeling is simply no. Even the other new CAD package announced this week is based on Parasolid, but handles history and features in pretty much the same way, with the same answer about direct modeling.

Solid Edge ST7, the current version, handles it all differently, so we can do both history-based modeling and Synchronous editing on the same part. The way we handle that is that the underlying base model is Synchronous, and you can do your direct edits to that. Then if you choose to, you can add history-based features on top of the Synchronous model. Or you can make a 100% Synchronous model. Or 100% history-based.

Solid Edge ST7 also allows you to make in-context changes without creating in-context references. So let’s see – no parent/child birdnests??? No in-context file management nightmares??? Sign me up!

The answer is flexibility to do things the way you want to do them. Not some half-fast half truths about if your CAD tool can do direct edit. Also, the power that you need has to do with design, and how you make changes, because that’s your job, not about IT and cloud applications. Spend your CAD money on CAD that empowers you.

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