The Javelin Technologies Blog

Alin Vargatu, a distinguished AE for Javelin, asked me to write a guest blogger article for Javelin’s blog. I’ve seen some of Alin’s very helpful comments to complex users questions in the SolidWorks Forum, and I’ve come to know him as one of the good guys when it comes to reseller technical folks. I’m a bit flattered to have a reseller ask me to contribute to their blog, especially one of the stature of Javelin.

Alin suggested a surfacing topic most relevant to the biggest number of SolidWorks users out there: How do you convince surfacing skeptics about the benefits that SolidWorks surfacing could bring to them?

Not an 'Andy Warhol Type'

When most CAD users hear the word “surfacing”, they think of one of two kinds of people: a guy who looks like Andy Warhol, smells of alfalfa sprouts and speaks in lofty metaphors, or a past-middle age CAD dinosaur who remembers the command structure of Computervision software, and speaks a lost vocabulary of arcane detail meant to make you quiver in stupefaction. Most SolidWorks users would probably find both extreme clichés difficult to work with. And I wouldn’t blame them. You don’t have to live in the CAD wilderness to make use of SolidWorks surfacing tools.

I don’t intend to try to convince machine designers that they should make swoopy sheet metal parts, or that splines are really the best way to represent your product. Those things have their place, and when I get to talk to Andy, we can chat up that stuff.

Most SolidWorks users are making shapes with extrudes and revolves. Maybe some fillets and a sweep here and there for tubes or wires. Machine design and sheet metal applications are more about the engineering than the geometry. Mold and die tooling are natural fits for using surfaces to split tooling, and if you’re working in those areas without using surfacing, you’re really missing out.

Surfacing for the Mold, Tool and Die Industry

Surfacing should be part of your every day modeling. It’s a repertoire, vocabulary, or toolset that you need to be familiar with regardless of how long you have worked without it, and regardless of what kind of geometry you make. Even people who model blocks with holes and sheet metal parts need to be able to use surfacing tools and understand how much power they give you. Everyone needs to know this stuff, and here’s why.

Surfacing is not just lofting and sweeping and the fill surface and the boundary surface and other stuff most people don’t know or care about. With SolidWorks surfacing tools, you can create planar, extruded and revolve surfaces, just like solids. You can create ruled surfaces, offsets, copies, move surface bodies, and other types of features that manage surface bodies rather than create new shapes.

Offset Surfaces

You get a lot of control with surfacing that the automatic nature of solids will never give you. Automation is great. It is fast, and saves you time. But you also sacrifice a lot of flexibility when you use automated processes. With surfacing, you can take apart a model face by face, and put it back together in a different way. That’s a type of control you will never have with solid modeling.

There are really two different ways you can use SolidWorks surfacing, regardless of what types of parts you model: 1) As reference or construction geometry 2) When building geometry face-by-face.

In the same way that you might use axes or planes as reference geometry, you can use surfaces make mates in assemblies, sketch on, extrude or revolve up to. You can show the intersection of two surfaces, or the intersection of a sketch plane with a surface. Surfaces don’t add to your mass properties, and you can hide or show them as necessary. You can use surfaces to represent other parts in your model or use a surface to cut a model.

Surfacing Example

The chances are that surfacing is not going to make you faster at anything. In fact, surfacing, especially initially, is almost guaranteed to make you not only a little slower, but much slower. I realize in this speed obsessed economy that isn’t much of a sales pitch, but what I have to offer is better than speed. Surfacing will give you CAD “super powers”. You will be able to do some things much more cleanly and accurately than you did before, and more than that, some things will be possible for you that were not possible before.

In those situations where you now just kind of hack together an approximation of what something looks like, you can actually be much more accurate when there is a need to do that. If you are using manufacturing that works directly from the CAD data like CNC or rapid prototyping, there is very often a need for total accuracy.

SolidWorks surfacing tools are actually very powerful. Don’t be tricked into thinking that because you think surfacing is a specialized niche, that the tools are somehow mainly pretty lame. It’s just not true. SolidWorks has the best surfacing of any of the mid-range mainstream modelers, and in many cases rivals the surfacing capabilities found in higher end software like Pro/Engineer.

If you deal with imported geometry, you almost have to use surfacing tools to get good results. You don’t have to know a Coons Patch from a Jefferies Tube, but you do need to understand how to take a model apart – not feature by feature like you do with native SolidWorks parts, but actually face by face when the need arises. Solid features don’t always arrange themselves into easy to deal with groups. When you learn to see your solid models as more than just features, the world of CAD becomes something you can control, no longer something that simply frustrates you.

Here are some hints that you may need surface modeling and don’t even know it yet:

• Do you find your self drawing lines in space that don’t actually make any solid geometry, just to close up a sketch because you have to have a closed sketch?
• Do you ever need to make a shape on the end of a feature other than what you can get by the default end conditions? (an extrude with a dome or non-planar face on the end)
• Do you ever find yourself tweaking a feature so that it doesn’t wind up cutting into or jutting out of the model?
• Did you ever wish you could edit an imported solid or repair an import that SolidWorks cannot heal automatically?
• Were you ever confused by patterns that would not let you pattern just the features you wanted to pattern?

Pattern Feature

• Have you ever wished you could make edits to parts without wrangling with complex feature trees?

Surfacing Example

You want another reason to learn this stuff? My SolidWorks Surfacing Bible was first published in 2008. At first it sold ok, but wasn’t doing very well in the Amazon statistics. It was and still is the only published book (aside from the SolidWorks training manuals) completely dedicated to surfacing in SolidWorks. Anyway, three years after the original publication, the book is selling better than ever. Now you might blame that on the economy, or an abnormally warm summer or an echo of a Jimi Hendrix riff, but to me what it says is that people are getting turned on to surfacing in SolidWorks somehow. The book has sold over ten thousand copies, and I know for a fact that there are a lot of regular (solids only) users reading the book, because they email me questions.

So the reason you need to know this stuff is because a lot of other people around you already know it, and the next job interview you go to, you might be up against one of them. If they know how to design the major components of an assembly as a single main shape, and then break the main shape into individual parts and make an assembly out of them automatically and you don’t, well, you gotta know this stuff.