BUZZ
The latest news about the industry and companies that use 12d Model. Who’s won what, who’s done what, and what’s in the pipeline. If you have some news – or know some news – about a project, let us know here.
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Newsletter
Rail transitions | Free 12d access for BOSSI candidates
12d Model upgrade seminars | Electronic lodgement of cadastral data | Roadflow | Drones on construction sites
Estimating rock volumes for Airds Bradbury Renewal
Pacific Highway detail design | Berry Bypass | RMS seeks interest from surveyors | Pacific Highway Upgrade project | Overnight success for Daly Smith | North West Growth Centre
Rail transitions cube up the error
Newscastle’s de Witt Consulting recently raised what looked like an unsolvable problem, related to one of their ongoing projects with ARTC that involve checking rail track alignment, and realigning if necessary. The team at de Witt is adept at creating Super Alignment from the ARTC’s SAS data — they punch in coordinates to create the SA strings, then upload to their Leica Viva instruments and use Road Runner for setout.
The system works well, until they encounter geometry that cannot solve. A section of the Ironbark Creek coal line was due for reconditioning — removal of the ballast, realignment of the track, replacement and re tamping of the ballast and re tamping. When de Witt’s Michael Henderson entered the data for a broken back curve with a cubic parabola transition, it would not solve.
de Witt’s work ended partway through the transition, so a workaround was found where the second curve was remodelled as a straight, the transition solved onto the straight, and the site work was successfully completed.
EXDS went back to the 12d Solution programmers to get to the root of the problem. They’ve explained that when a cubic parabola is used to join two large radius curves — as in this case — shift is very small, and the ‘m’ in the formula y=mx3 becomes very very small, (10-6 or 10-7), while the x3 becomes very large. There are intrinsic problems with floating point calculations when a very small number is multiplied by a very large number, and sometimes — as in this case — a solution cannot be found.
Interestingly, the problem is most apparent with cubic transitions, and 12d Model has a better chance of finding a geometric solution if a natural clothoid is used.
BOSSI Candidates get free access to 12d Model
The Board of Survey and Spatial Information of NSW (BOSSI) has the role of assisting and assessing candidates to become a Registered Surveyor. One of the criteria that Surveyors must meet for Registration is to demonstrate competency in Engineering Design, and the Association of Consulting Surveyors (ACS) runs a course to develop and demonstrate this competency.
Some Registration candidates work in Surveying firms without access to suitable design software, and EXDS has agreed with ACS to loan full working copies of 12d Model to candidates doing BOSSI Workshop. At the last workshop (May 2014) six candidates successfully took advantage of a loan license of 12d Model.
Do you have news about a project? Let us know here