RE: How do I keep my LandXML file edits from Trimble Business Center

Katie Cook — Wed, 17 Mar 2021 19:01:55 GMT

Victor,

While searching for my own answers to a related question, I came across this and thought it might help you. (Refer to link for full article.)

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To export intelligence with the triangulated surface, you must include the features which have names and styles.If you take the time to delete triangles from your DTM or change a triangle edge, those changes will show up in the <Faces> block in the LandXML file. If the receiving software cannot process <Faces> the triangle edges will not be used and the triangulated surface after import will not exactly match the surface that you exported. Some applications will use the <Faces> information, like Civil 3D or Trimble Business Center, but not all civil design applications use the triangle edge information, and InRoads V8i certainly does not. InRoads V8i will export <Faces> data, but will not import triangle edge information and must triangulate an imported surface itself. Differences in the maximum triangle length and deleted or changed triangles will cause the surface that InRoads V8i creates to be triangulated differently. That means that if you transfer surface data in LandXML format to someone using InRoads V8i, the surface that is received may not exactly match the surface you export. One method of forcing identical triangulation by software that does not process <Faces> data is to import the triangle edges into your surface as breaklines prior to exporting to LandXML. After importing the LandXML file, the triangulation must be performed without limiting the triangle length.

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file:///C:/Users/h7etdkrc/AppData/Local/Temp/1/Surface_Export_Import_Using_LandXML.pdf

Best,

Katie

RE: How do I keep my LandXML file edits from Trimble Business Center

Ray Thwaits — Mon, 24 Feb 2020 21:36:10 GMT

Whether you import your LandXML file into an InRoads surface or a MicroStation terrain model (not there's any value to that with SS2), it will be re-triangulated. It doesn't matter if the LandXML file includes points and lines or points and faces or both, it will be re-triangulated based on the points and lines in the first and third cases, and on points in the second case; i.e., it will ignore the faces. When based on points and lines the differences are usually insignificant. Obviously, you're finding some significant differences in your surfaces. I know of only way two ways to force identical triangulation: export triangle edges as breaklines or import the triangles from graphics in a dgn or dwg file.

I'm not clear what you mean by your edits not matching. If edits to points or breaklines aren't carried over from TBC, I would suspect that TBC isn't correctly exporting your final surface. Edits in TBC such as flipping triangle edges or deleting edge triangles will only be exported to a LandXML file if the faces are exported. Since InRoads ignores the face definitions, those edits will not be reflected in the InRoads surface.