www.engineeringnews.co.nz 9 then it suddenly doesn’t work any more.” It wasn’t until people started to realise how complicated the geometry could become, especially as the facade goes round a curve, that the whole engineering design had to change. The steelwork junctions were equally complex. It was decided that the nodes should be simple hexagons that varied in shape to accommodate different steel section sizes. One of the most difficult problems was to find the normal to 6 (or 7) triangles meeting at a single vertex or node, which would be valid in both concave and convex situations. This made the node design uncertain and gave rise to nodes that varied from a simple hexagon to unique six sided nodes whose sides varied in length depending on their orientation. Inventor’s iLogic tool enabled designers to place a generic node, then configure it to suit the conditions. “There were several occasions where we just ran into roadblocks and we couldn’t figure out how to get round some of the problems,” says Crawley. “And in most of the situations things were resolved by people having lastminute inspiration while they were taking a shower or similar. Once one problem was solved we just moved onto the next one until everything was fixed.” “Almost by accident we discovered a repeatable technique to build complex manufacturable assemblies against a simple point cloud,” says Crawley. “With this technique, any shape made from triangular facets like this becomes surprisingly quick and easy to build. “One of the other features of Inventor, which saved considerable time for the designers, was the ability to emboss each component. In any given model you had maybe 20,000 components open, it took a finite period of time to interrogate each part by accessing its properties to identify it. To avoid having to do this, 4DFS embossed the part number and the grade of the material on each part. When the designer was moving around in 3D space, he could interrogate the part by simply inspecting the embossing. “It’s like engraving the part number and the material specification into the part,” says Dent. The embossing was kept on the part and it was a considerable aid to the construction process in the workshops in China. This also enabled any 3rd party review process (like DWF and Navisworks) to work without any additional data being provided. “The generic iLogic steel component was also designed to change colour if you changed the section size or grade of steel which made downstream inspection (in say Navisworks or DWF) so much easier,” says Crawley. “On many occasions, new design criteria or steel sizes were added, and iLogic was able to update every single part already made. “There are some new Autodesk tools like BIM 360 Glue and Mockup 360 that would have saved us weeks of time collaborating with stakeholders around the globe, but at the time we just made good use of Autodesk DWF files and some screen sharing software,” says Crawley. The iLogic tools and programming interface in Inventor simplified even the hardest problems. “Sure it took some effort, but who’d have thought Inventor would be able to export building survey data directly from the 3D model?” says Dent. “We were able to fabricate the steel without producing any drawings. All the steel junction pieces were CNC machined directly from our 3D Inventor models.” As the building was symmetrical about a central plane, Inventor simply mirrored every component. However, simply mirroring embossed text just reversed it. Making the text readable again (and changing the lettering) was another problem solved using more iLogic and Autodesk Vault which made very short work of renaming and renumbering thousands of parts and assemblies. “We didn’t really have any other option other than to make the thing work otherwise someone was going to have an awful lot of glass for their greenhouse,” says Dent. “And we had to order everything in batches so that we could get it all locked in with the supplier.” The results The glass panels were made in China and assembled into their aluminium frames in North China. The steel was made in south China and then it was all shipped to Adelaide. The glass and aluminium was fitted to the steel in Adelaide. “It all fit together without any specialised hand finishing,” says Dent. “And the factory didn’t need any fabrication drawings.” The 2D design of the steel was still going on when 4DFS were doing the glass. “When you think about how separate all these different projects were, it’s incredible that it ever came together,” Founder of 4th Dimensional Facade Solutions says Dent. In a situation where the whole design exercise was not following the logical design or manufacturing sequence and given the situation where some parts had to be ordered before the rest of the design was complete, it speaks volumes for the experience and ingenuity of those involved that the project was successful. It also speaks volumes with regard to the flexibility, sophistication, maturity and quality of the Autodesk Inventor software that it could accommodate an architectural design project of this magnitude. It’s true to say that without Autodesk Inventor this project couldn’t have been built. EN
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