Does anyone know if and how we could access additional structure information from an IFC object.
Let's look a small simple disc as an example.
The screenshot is from Access. There I can select the face or the circular polyline around it.
Looking at the IFC text file, the dark blue line is made up from vertices -> IFCPOLYLOOP
.............
#140= IFCCARTESIANPOINT((3.,-9.5,-356.247813));
#141= IFCCARTESIANPOINT((3.,-13.435028,-359.267265));
#142= IFCCARTESIANPOINT((3.,-16.454482,-363.202274));
#143= IFCCARTESIANPOINT((3.,-18.352591,-367.784739));
#144= IFCPOLYLOOP((#120,#121,#122,#123,#124,#125,#126,#127,#128,#129,#130,#131,#132,#133,#134,#135,#136,#137,#138,#139,#140,#141,#142,#143));
#145= IFCFACEOUTERBOUND(#144,.T.);
#146= IFCFACE((#145));
which is further used to define an
-> IFCOUTERBOUND
and that one to define an
-> IFCFACE
The initial file came from a third-party software and was imported into TBC, relayered and recolored and then exported as IFC. So, I must assume that the IFCLOOP information is kept somewhere.
Is it possible to retrieve those.
Reason being. One of our guys asked if we can easily mass retrieve the center lines of steel plate holes. If I could retrieve all the IFCLOOPS I could just compute an average into the loop vertices.
Worst case scenario would be to parse the IFC file itself. I'd have to have a closer look at that local to global transformation though. The vertices are saved as near zero types, with some kind of shift and rotation.
I myself don't trust the IFC to that point yet. There is always a paper drawing with intervals I can hack into Excel and compute the points along a stringline. And often enough they don't match. Sometimes the IFC is wrong and sometimes the paper drawing. Always need to double check the dimensions with the steel and hole patterns that's being delivered to site anyway.
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Ronny Schneider
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