By Jim Foster
One of my favorite bloggers, Matt Lombard, made several posts a few weeks ago pertaining to “Design Intent.”
When Design Intent Unravels: Part 1 http://ontheedge.dezignstuff.com/when-design-intent-unravels-part-1/597
When Design Intent Unravels: Part 2 http://ontheedge.dezignstuff.com/when-design-intent-unravels-part-2/617
In the example Matt presents, a simple part proves to be more painful than it should be to capture the desired design intent. In this case the “intent” is to make several holes concentric to rounded edges created as rounds. The feature order, parent/child relationships and types of features used all play a role in complicating this seemingly simple goal.
The example may seem trivial, but when using today's leading 3D modelers, we’ve all had to place a great deal of emphasis on dimensioning schemes, feature order and parent/child relationships. Ignoring these three advanced modeling topics can cause time consuming surprises when trying to create or change designs.
In “Part 2” of the discussion, Matt presents the benefits of direct modeling techniques to capture the desired design intent with the same part.
If I take Matt’s posts a bit further and compare the two modeling methodologies, to To3D, our goal is to let the designer or engineer capture the design intent through sketches that are dimension-driven and constrained in a 3D environment, without regard to solid features or feature order. This methodology allows features to be much less dependent on each other and feature order.
In the example below, I recreated the part Matt presented as closely as possible with one exception; I did not use rounds where Matt did. As a result, the only feature in this model that is order dependent is the first feature, both constraints and feature order can be changed without the stereotypical problems shown in Matt’s example. Note: As we develop round/fillet capability, it will not alter the outcome of this example when rounds are used in place of the cuts.
In the example below updating the design intent as Matt did is trivial because it is so straightforward in To3D. To start the interactive demonstration select this link or click the image below.
Note: A browser that supports WebGL like Chrome or Firefox must be used for the demonstration to work.