Machine Design

A smarter CAD alternative

A "smart," easy-to-use, 3D-surface solid-modeling software lets industrial designers be more creative.

Nelson Au

The hard-drive portable device was designed in Cobalt.

Design files were exported to a mechanical-engineering team and developed into a finalproduction part.

A photorealistic rendering of an MP3 player was done with Cobalt's built-in rendering engine.

Cobalt is a product-development tool with associativity, history, and dimensional-constraint capabilities. It (along with Xenon and Argon, which are 3D-modeling packages with fewer capabilities than Cobalt) is available under Ashlar-Vellum's Designer Elements name.

Cobalt has the same interface as the original 2D Vellum CAD package (now called Graphite). This simple, elegant, and intuitive interface lets users focus on design, not the software. Take the Drafting Assistant, for example. When you draw a line, it helps draw it along any of the three axes, or at 90 or 45°. And when you draw a circle on the line, the Assistant asks whether the center should be on the end or midpoint. Designers can begin creating organic forms or building-up straightforward mechanical parts in a short time, often on the first try. For example, I took a three-day training class and learned enough to start working right away.

Designers can also edit solid parts with tools such the blend tool to add fillets, drill holes, remove material, and add material. Additionally, they can edit splines that define solid-part curves. Similar to the arc tools in Adobe Illustrator, users activate control points on curves to modify them. After editing a spline, Cobalt updates the model.

For parts defined by rectangles, users can select an end point on the rectangle, and then drag or move it to update the design. To modify holes that are too small or shallow, merely call-up the Get Info dialog box to change hole dimensions.

A Cobalt tool proved handy on a recent project involving the design of a product with a highly tactile area. A physical model was required for hands-on testing of button shapes to validate the design. Using the STL output option, I exported an STL file and e-mailed it to a model shop for a quote. The shop explained that because the part was a solid, the volume of material required to make it would be quite expensive. But using Cobalt's capability to shell solids, I hollowed the solid and reduced its volume. I then used the Verify menu to check the volume,area, and other properties. This let me adjust the part size to achieve the target volume and meet costs.

After a design has been developed, a client might require a way to visualize it. Cobalt, Xenon, and Argon software all include a rendering engine. It takes little time to set up a rendering with light sources and a background surface on which to cast shadows. The built-in engine has a range of materials that can be applied to models including metal, wood, glass, and plastics. For more-advanced users, Ashlar provides CDs with additional materials.

When it's time to exchange CAD files with design and engineering colleagues, the software presents options to export several formats, including STEP, IGES, ACIS SAT, and DXF. ACIS SAT is the best option for importing because Vellum Cobalt is based on the ACIS kernel. In the time I have been using Vellum Cobalt, I have had very little difficulty importing and exporting files from Alias, Pro/E, RhinoCAD, Inventor, and SolidWorks users.

Users can also create Fly-By and walk-through animations of models built as Quicktime movies, useful for letting colleagues or customers review designs.

The software runs on both Windows XP and Macintosh platforms. For Windows, Ashlar suggests a Pentium 4 with a minimum of 512 Mbytes of RAM, but 1 Gbyte is recommended. For the Mac OS, Vellum runs up to OSX 10.4 with similar RAM recommendations on G3, G4, and G5 processors. The software is available through Ashlar dealers or from Ashlar online for downloading. The work discussed here was created on a Macintosh G4 Powerbook and G5 desktop system. I have also used Cobalt on a Dell M70 laptop. The software operates identically on both platforms.

The software comes from Ashlar Inc., 12710 Research Blvd., Suite 308, Austin, TX 78759, (800) 877-2745,

Nelson Au is a practicing industrial designer currently with designafairs USA. He has 20 years experience and was a founding designer of IDEO. He can be contacted at (650) 694-5329,

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