I might be wrong, but I think it has happened on multiple projects after using the RPS convert to line string command. Bellow are 2 examples from most recent project. I’m confused how the elevation is -157258.847 when the min is 558.276 and the max is 559.068. I would like to know a simple way to fix without deleting the whole line.
When exporting to earthworks, it ends up looking like a tangled bundle of strings.
If I’m not mistaken, its the UCS data has something to do with this issue. in the convert to linestring command, try using the check box to remove UCS data.
be sure its the RPS convert to linestring and not the TBC version.
Your 100% correct, I tried to join to lines together, One was bad line and other was normal. I got an “unable to join lines because different ucs data” error.
Great question and shows the undeniably quirky nature of CAD data
Your screen grab shows that you selected a Polyline. It shows that that Polyline has UCS values these are USER COORDINATE SYSTEM values - these define a new X,Y and Z axis for the line, and in that coordinate system the line has a single Elevation value of the 157258.847 i.e. it is 2D in the plane of the coordinate system, however in a normal Elevation = Up coordinate system, the line is 3D and has elevations in the range 558.276 - 559.068
The UCS defines a tilted plane on which the line is drawn in AutoCAD, and allows AutoCAD to create a 2D line in space that has a constant elevation, that then in normal coordinate space looks like a 3D line. To be able to use such a line, your software has to understand what to do with lines that have different UCS properties - Earthworks and GCS900 do not understand UCS at all.
The Convert to Linestring command has a remove UCS option that allows the UCS properties to be removed and the line gets recomputed as a true 3D linestring in TBC - those 3D lines are compatible with GCS900 and Earthworks.
The reason that Earthworks shows what it does is because it is trying to read the line as a normal CAD line, but is ignoring the UCS component which is 100% necessary to get it in the correct place in 3D space - without the UCS - the line will be totally meaningless and likely very very incorrect
This is why we create and support such cleanup tools
When you import CAD data you should always run RPS CAD Cleanup, optionally Project Cleanup and then run Convert to Linestring to fix these CAD problems before you attempt any Takeoff or Modeling procedures on the data.
CAD Cleanup does a 100% correct job of recomputing the line into the Z up coordinate system, which may include modifying a radius value of an arc to make it fit when drawn in plan view (in AutoCAD they draw the arc on a tilted plane so that they can make it 3D on that plane, however that really does not work at all for site project issues like Parking Islands, Curb Returns, Curb Lines etc., as it is not always that the curves are planar, they often have vertical shape that is not planar, and AutoCAD cannot model that without chording the arcs first - this is AutoCAD’s biggest limitation in my view by far.
Hope that this helps
Alan
