SolidWorks 2011 Measures Up

9 Sep, 2010 By: Bill Fane

The latest release from Dassault Systèmes features automatic dimension re-arrangement, a part de-featuring tool, and simple sharing of parameter values and equations between parts.

Well-known CAD writer Ralph Grabowski produces a weekly e-mail newsletter called upFront.eZine. A while back he asked his readers if the use of CAD was resulting in poorer drawings, and the response — especially from his older readers — was a resounding "Yes!"

My personal beef comes from sloppy dimensioning. Engineering drawings are a form of language, used to communicate ideas. If in a sentence in the sequence wrong the words are then harder much it becomes read and comprehend to. Huh?

The same is true of engineering drawings. If dimensions are poorly placed, they become harder to understand, and it is more likely that mistakes will be made. The problem is that most schools and institutes these days turn out "CAD operators"; they may know every command in a particular brand of software, and have a certification to prove it, but that doesn't make them good drafters. Dimension placement is a prime example, especially in 3D parametric modelers that automatically bring dimensions forward from the 3D model to the 2D working drawings.

Fortunately, one of my favorite new features in SolidWorks 2011 pretty much solves this problem. (Dassault Systèmes unveiled the new version at the beginning of this month, and invited members of the CAD media to get a first look at the software; I'll discuss some of the most intriguing updates here.)
After you place or retrieve dimensions into your 2D working drawing, they can be automatically re-arranged according to "traditional" drafting rules. They are placed:

  • Outside the part
  • Spaced from smallest to largest
  • Aligned and centered, if possible
  • Equally spaced
  • Adjusted to avoid overlapping
  • Staggered, if necessary

A typical drawing "as produced" (above left), and the same drawing a split-second later, after the dimensions have been automatically re-arranged (above right).

As you can see, the resultant drawing is easier to read and less likely to yield reading errors.

I Won't Show You Mine

Another valuable addition to SolidWorks 2011 is the DeFeature tool. In a very common scenario, you have put a lot of time and specialized knowledge into creating a design for an assembly, such as a new pump. You are now ready to sell the pump to your customers, but they want a 3D model of it that they can insert into their machinery model.

The problem is that you don't want to turn over all of the component part files required, and thereby give away your design knowledge. On the other hand, most customers won't even want the clutter and speed reduction that come from having all those extra files.
The new DeFeature tool neatly takes care of this situation. When you invoke it, it automatically selects every feature of a single part, or every feature of every part within an assembly that originally subtracted material, and replaces them with solid material. Overlapping resultant solids are also eliminated, so that when a cavity is eliminated it also takes out any parts or features located within the cavity.

You are allowed to select individual parts within an assembly, and/or specific features within parts, to not be de-featured. Significant subtracted features (such as mounting holes) can thus be retained.

SolidWorks 2011 then produces a new, independent model file consisting of a single "dumb" solid. It loses all connection to the original component parts, so the single file can be sent to other users without having to send them the component part files.

To answer your next question, even though "subtract" features have been replaced by solid material, the new de-featured part retains the same mass properties as the original part or assembly. In addition, constraint relationships can be maintained so that the output shaft of a de-featured gearbox still turns at the correct ratio relative to the input shaft.

Kindergarten Rules

Every kindergarten graduate knows that they should share their toys. Sharing of parameter values and equations between parts is very easy in SolidWorks 2011; simply export them from one file and import them into another. The only major requirement is that the appropriate parameter names must match between the two parts.

In our earlier gear-type pump, for example, we could have equations within the pump casing that calculated the diameter and depth of the casing based on the input speed and the delivery volume required. Next, the equations and values can be exported from the casing and imported into the rotor; rebuild the rotor and it updates to match the casing. To make things even easier, both parts can be linked to the exported/imported file so the two parts will always stay in step. In a brilliant move by SolidWorks programmers, the export/import file is a simple text file that can be edited or even created with a generic text editor such as Notepad.

Getting It All Together

Weldments are a very common manufacturing process, especially in the machinery industry. In earlier releases, weld beads were added as assembly components. SolidWorks 2011 allows you to easily and quickly add simplified weld bead representations, including beads that fill gaps.

In addition, fillets and chamfers can now be applied as new features on parts within an assembly. A common application for this capability would be in performing edge preparations before welding parts together. The edge preparations can be made to reflect back to the base parts if you want, but edge preparations are typically performed in the welding shop, not the cutting shop.

Four Down, Almost 200 to Go

Two hundred seems to be a magic number in the CAD programming world. It's that déjà vu thing all over again: it seems that almost every new release of a CAD program has about 200 new or improved features, and Dassault Systèmes SolidWorks is no exception. The "What's New" PDF file runs to 170 pages. I can't cover all the changes and additions here, but it is almost certain that you will find a few new features that will help you in your day-to-day work.

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Re: SolidWorks 2011 Measures Up
by: cadcoke5
September 17, 2010 - 11:47pm
I have always had problems trusting dimensions coming in from models. The example in the article give the correct 4" vertical dimension. But, in my past experience, it would sometimes dimension the straight vertical edge, and be short the fillet radius. On a large radius, it is easy to detect. But what if it is a small one? I am sure past automatic dimension errors were due to the way the modeler did his work, but I don't blame the guy who modeled it. I don't want to trust an automatic dimension system that is sometimes the wrong value. Joe Dunfee
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