Let’s talk about point clouds, Geo Referenced drawings and Plant3D. The use of GeoRef data is common place when dealing with the utilities industries. Customers like to give us site plans that we can pipe around, and sometimes even 3D models of these sites. That is brilliant, and should you receive a point cloud then that’s even better. For new installation, the site plans or point clouds can be invaluable as it allows us to route our pipework, and place equipment so that it does not interfere with existing kit. We do have one small issue to address however, that of scale.
Anyone who has been given Geo Referenced data will know that the drawing / pointcloud contains some big X and Y values. This is due to the 0,0 for the easting and westing being from a point about 150Km out to sea from Penzance.
These big numbers present a challenge to Plant3D due to the number of decimal places too. If our data is positioned somewhere in Norfolk, the AutoCAD drawing is at least 630Kmx330Km big. Now if we are dealing with large civil or mapping features all is well, however as a piping engineer we are dealing with small pipe entities. If we were to try and route a pipeline based on a model that large, well let’s just say it does not work. Auto route just will not connect, and we cannot even route a straight section of pipe.
The fix is simple, choose a suitable reference on the supplied data, and take careful note of its easting and westing. Now move the entire data such that the reference chosen is on 0,0. This gives us a drawing that is the size of our site NOT the entire country. We can route around this model and create our plant design, happy times, the software is working and we have a functional design. The problem comes when we have to supply the design back to the customer on the previously supplied Geo Reference point.
The solution is to XREF our design into another drawing, and offsetting the XREF by the previously noted values. Now you may wonder how all of a sudden it works with these big numbers again, it works because we are not editing or adding small pipe features to this drawing. As the new drawing is viewing only the size is not an issue. If we need to edit the design, it is done so in the drawing with a local 0,0.
There is an AutoDesk white paper called Using Plant 3D in a State Plane Coordinate Project Environment that covers this for US based systems.
To find out more about AutoCAD Plant 3D just head over to our software page or give us a call on (023) 8086 8947.