The big deal with Solid Edge ST3

Solid Edge ST3 combines direct modeling and history functionality into the same part. In the past, you had either a synchronous part or a “traditional” part (they are dropping the word “traditional” and going with “ordered”). The part has a “Synchronous” section which is essentially a base body, and an ordered feature list. “Ordered features” is just another way of saying “history tree”. From a SolidWorks point of view, you can think of the body data in the Synchronous section as imported data or an inserted part. It is “dumb” in the SolidWorkssense (has no features), but because of the direct edit tools in Synchronous Technology, it is very far from dumb.

The image above is taken from a Solid Edge part. Features in the Synchronous list act as selection sets of faces. They are not associated with sketches or feature based parameters. If you click on the Protrusion4 in the Synchronous list, you merely select all the faces associated with that feature – the faces that feature created. The Used Sketches folder keeps sketches that were used to create synchronous features, but the sketches are not linked in any way to the geometry.

The Synchronous list is above the Ordered list because the Synchronous body is the base geometry that the Ordered features were built on. Exactly the same as importing a part intoSolidWorks and adding features. Except that Solid Edge has strong direct edit capability, andSolidWorks has comparatively weak direct edit capability. When you make a “synchronous” change to the part, it rolls you back to the body data, before all of the ordered features.

Ok, let’s talk about something else while all of that sinks in a little bit.

When I wrote the post about improving history based modeling, I started from a base assumption of SolidWorks, and tried to suggest some improvements. One of the ideas that came out of that was to allow Freezing features (which failed to make it into SW2011, although it was close). Freezing the tree would essentially take part of the tree and make it into a static (dumb) solid, but with the caveat that you could thaw it at some point. So, this idea that came from that post and comments is similar to what Solid Edge has done.

If you assume that the Move Face tool in SolidWorks is essentially equivalent to the direct edit type functionality in Solid Edge (in reality the SolidWorks functionality is probably less than 10% of the Solid Edge functionality), the SolidWorks way of taking a Move Face feature and putting it into the history tree presents a conceptual conundrum. One of the selling points of direct edit is that it removes the rebuild time and feature order difficulties associated with history based modeling. To then take a direct edit feature and make it a history based item that itself has a rebuild time associated with it is like pouring gasoline on a fire. TheSolidWorks implementation of Move Face and other direct edit tools is a “best practice” nightmare, which I have written about several times on this blog, and in my books.

How would you address direct edit capabilities without introducing this or a similar conceptual defect? One way to do it would be to do exactly what the Solid Edge folks have done in ST3. Direct edits are not recorded as features, only the results of the change remain. History based features like fillets and shell are executed in an ordered list of features. It really is the best of both worlds.

Remember that I was very skeptical about ST1:

Solid Edge with Synchronous Technology is a nice alpha version of the software they are should one day create.

I didn’t just change my mind. ST1 was weak because it assumed you could do everything with direct edit. I don’t think you can. Combining these direct and history I think really is the best way to go. It’s the best way to go for both history and direct modeling. They need one another. There is no reason to be so either-or. Both tools are useful, and they have different strengths and weaknesses, and there is no reason why you can’t put them together, as SolidEdge demonstrates with this release.

You can open Solid Edge ST3 and work in either completely history based or completely synchronous workflow and toolset. This is fantastic. You can convert all or just a portion of your history based model to synchronous, but you can’t convert synchronous to history based. I think this last point was the one opportunity I found for significant improvement in ST3. If you were able to make part of the history model into synchronous, and then be able to bring that portion back to history based, that would be roughly equivalent to freezing the history tree and thawing it. There is no sense in throwing away information. I think you could take ST a step further, and freeze a window in your tree, possibly even multiple windows, and it would be great if it didn’t have to be stuck at the top of the tree.

I asked Dan Staples if he thought combining history and direct edit is really the best idea or if it is just the best compromise. He conceded to me that he thought it was just a compromise, and that he still really believed in the ST idea. This is one point where I think I disagree. I don’t see direct edit as a tool that can handle every situation. I do see history as a tool that can handle everything, but it has some significant limitations. I really believe that combining these two methods, each covers the weaknesses of the other, and in the end you have more options. Maybe it is an inherent compromise or maybe it is just adding one set of tools to another set of tools, but I think this combination of work methods is stronger than either method on its own. To me, that’s really what it comes down to. It’s not just combining feature sets, either. I think there are things you can do with these tools together that you can’t do with either one on its own. It’s a bit of brilliance.

So, what are the implications of working with both direct edit capabilities and history based capabilities?

• Data imported into Solid Edge is roughly the same as native data
• Solid Edge will never have the same sort of problems with version compatibility thatSolidWorks has, because you will never completely lose your ability to make changes by sending a Parasolid back one version.
• You don’t have to throw away the concept of design intent.
• You can work either way, and don’t have to curse when someone sends you an imported model, or when the history based model they send you is a mess, history-wise.
• Changes to the synchronous model update the history-based part of the model.
• If, as Dan S believes, Synchronous really is the best way to go, combining direct and history modeling  is at least a good bridge for folks like me who still believe that history modeling still has a lot of value.

I’m going to write a few Solid Edge ST3 posts on the following topics:

• multiple bodies in Solid Edge
• the Blue Dot
• Surfacing Tools in Solid Edge
• Dealing with imported drawings in Solid Edge
• Synchronous Sheet Metal
• Synchronous Assemblies

If you want to suggest more, please leave a comment.