Knowledge base
What should you supply?
A good model starts with complete drawings. An overview of what we need, in which form, and which information is often forgotten.
The drawings
The more complete the package, the faster and more accurate the model. Ideally send everything the contractor uses for construction:
- layout or general arrangement plan with coordinates;
- long sections of roads, pipes and ditches;
- cross sections or typical sections with build-up and crossfalls;
- levels: floor levels, manhole covers, kerb heights, finished levels;
- survey of the existing ground, if available;
- detail drawings of tie-ins, accesses, junctions or excavations.
In which format
Digital CAD files (DWG or DXF) are preferred. They contain the real coordinates and often 3D lines or spot levels already, which makes modelling more accurate and faster.
PDF can also be used. The drawing is then scaled and placed on coordinates using known points or the grid on the sheet. This takes more time and the accuracy depends on the quality of the document. A scanned paper drawing is the least accurate.
Do you have a survey or model in LandXML, or an earlier design in another format? Send it along; it can serve as a check or as a starting point.
Ideally send the original drawings as the designer produced them, with their layers intact. Edited or stripped-down versions sometimes lose exactly the information the model needs.
Coordinate system and height datum
State which coordinate system and height datum the project is drawn in, and which system the machine works in. If this is not on the drawing, we propose a common system based on the country and location of the site and ask you to confirm.
If the machine uses a local site calibration, also pass on the control points used, with their coordinates. That makes it possible to check that the model and the calibration agree.
Practical details
Besides the drawings, a few details help us plan the job properly:
- site address or location (town, street or coordinates);
- make, type and software version of the machine control system, per machine;
- which layers or stages you want as separate surfaces (for example excavation, sub-base, finished level);
- the required delivery date;
- a contact person who can answer questions about the design.