Articles, Modeling, Siemen's PLM Software NX

The NX8 Conic Blend

By Stephen M. Samuel PE

 

Creating Beautiful Designs

The conic blend answers the question “How do I step up my game in my efforts to produce designs that are not only durable and functional but as beautiful as they can be?”. There is a reason the conic blend is inherently more pleasing to the eye. The conic blend can transition from a flat surface to the round shape of the blend more gradually than a normal blend with a circular cross section. Unlike a normal blend which makes an abrupt transition from a flat to whatever radius the blend has, the conic blend increases in curvature according to a parameter called Rho. When you experiment with a range of values for rho you can get the light bounce off of both surfaces in a way that appears smoother.

The conic blend is also an upgrade in appearance due to the fact that it is a departure from the norm. For many years people who designed products using CAD had little choice. Blends were clunky but it was the best CAD had to offer. Consumers weren’t expecting as much so it was OK.  Although the NX system has had the conic blend available for a long time in the “Face blend” command, it is now more accessible in the “Edge blend” command.

 

Figure 1. Conic blend menu and an example

In general, those in the industrial design field have always wrestled with the problem of tools and material, limiting the geometry that they would like to see on the products that they defined. There’s a lot to be said for the old fashioned way that many industrial designers would work. They would work in clay and plaster and they would work with their hands and hand tools. In some ways and for some types of products they were much closer to the products that they designed and the shapes had more feeling and meaning. The move to digital and CAD has such a long list of advantages in the manufacturing side that it makes all the sense in the world to keep doing it but to this day, certain aspects of analog can still have advantages over digital. One glaring example is the radio. In the days before digital you would spin a weighted dial to find a station. You could get from one end of the dial all the way over to the other with one spin, hearing a blip of the stations in between. These days, although you have 20 preset buttons that you can press to get a perfect digital lock on a station, it is still more difficult and slower to search through stations digitally. Another example is the e-reader. It’s great that you can use your e-reader to carry hundreds of books and you can highlight an unfamiliar word and instantly get the definition, but there’s something about the feel and smell of real ink on real pages that is missing. But, as all of this relates to CAD and the conic blend, the point is designers and engineers, in order to realize the great benefits of doing their design on the computer and not with clay, need all the functionality they can get in a CAD tool. This way designs won’t be constrained by the limits of what the software is capable of. Designers should have a massive CAD “vocabulary” with which to define anything that emerges from the deepest most creative parts of their brains.

If you compare the conic blend from above to a conventional circular blend that comes to the same maximum center point you can see that the takeoff points in the conic blends are a lot further back. This means the conic blend has a longer transition from straight to curved.  This is why the light that bounces off the product doesn’t appear as harsh. It is softer and looks more like something that grew rather than something that was manufactured. In many ways nature is the designer whose work many of us admire most.

Figure 2. Conic blend compared to circular blend

The NX8 Conic Blend v2.zip (108 KB)

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