Wednesday, September 22, 2010

Bentley 2010 Design Competition Winners

Today’s guest blog was contributed by Fran Rabuck, Director of Technology Research for Bentley Systems. Fran is responsible for the lab, and he works with RFID, Sensors, Visualization tools, Next Generation Input devices, mobile and wireless gadgets, and 3D Printing technologies.

At the Bentley 2010 BE Conference, Bentley hosted a competition for three teams, each consisting of two end users paired with a Bentley employee Microstation expert. This Iron Chef-like bake-off challenged each team to design and build a new Philly related iconic-like item that would represent some unique part of Philadelphia. All of their work would be projected onto a large screen live. Talk about pressure! First, the teams needed to choose what they would design, and then they had about an hour to model it. When the teams started their design, there was no mention of 3D printing of their work. Below you can see the results of the teams who designed: 1) The New Liberty Bell, 2) The Cheese Steak Trophy and 3) The Love Shack. The first two, most people are familiar with the association with Philadelphia. The Love Shack is a reference to the famous LOVE statue in Love Park across from City Hall. It’s a reference to the City being known as the “City of Brotherly Love.”

Now, even with the Microstation tools and help of experts, it can be a real challenge to design anything in an hour. The surprising result was all three models were loaded into ZPrint/ZEdit Pro and required very little preparation. Of course, these models were relative simple in structure and that might be expected. But so often, I hear that models need to be “designed from the start with 3D Printing in mind.” I’m not sure this is always true. Recognizing that more complex Digital Terrain Models (DTM), Building Structures and even Digital Plants can be very complex for 3D printing, there are several commands added to Microstation to aid in the preparation of a model for 3D printing.

For example a Civil DTM may include a set of unrelated triangles. These can be converted to meshes using the tool “Stitch into Mesh” or “Construct Mesh from Contours.” Or a B-Spline surface can be converted to meshes using the tool “Mesh from element” using a selection set. Solids can be created from a curved object using the “Solid by Extrude Along” tool. Surface objects can be fixed with the “Solid by Thicken surface” tool and the “Mesh from Element” tool. Sizing problems of Solid Objects can be handled with the “Remove Entity by Size” tool to remove small, print-challenged scaled objects. There are many other tools now in Microstation v8i like: “Add Thickness by Vortex offset”, “Add Flat Base”, “Mesh – Unite, Intersection and Subtract” and “Decimate and Cleanup Mesh” and more.

The last step, of course, is export to a 3D format acceptable by Z Corp. or other 3D printers. STL is the base standard and has been an option in Microstation for years. For color – VRML output can be used. But the lesson here is that exporting or saving models to STL or other formats should be the last step of the process for 3D printing. Don’t let any software vendors or 3D printer services lead you to believe that 3D printing is simply a single push-button solution.