Why does a building not show up in the profiles?

Even though a building is correctly specified in the noise module with a certain roof height, it doesn't always show in profiles drawn during calculation or with the Check profile… function. What happens?

This can happen if the building is defined with two “turns”. Point at the building line and select Modify, Properties. In the line with Vertex in front, browse through the vertices with the arrow button to the right of the point number. During browsing, you will see a white cross in the drawing, marking the point. If you see that you go “twice around”, the polyline representing the building is defined in such a way that it lies one time extra on top of itself. This confuses the profile calculations and will also lead to a higher calculation time, because the number of building lines is doubled unneccessarily.

A functionality to automatically detect this situation and warn about it is included in the wish list for a later update.

Why does this happen?

There can be several reasons:

This has shown up frequently after the introduction of SOSI4. After this, it is more common that a building line is not drawn as a closing polygon around the building, but split up into more specified parts. To join these parts, as the noise module needs it, many use AutoCAD-functions or the test command vnnp_noiseplinejoin in the noise module. If you do this once, then are not happy with the result and run the command again without deleting the existing lines, the first created lines will be joined together with the original lines and create another “turn” in the spiral being the joined building line.

To avoid this, always think of creating an AutoCAD map from the terrain model and defining buildings in the noise module as a one way process. If things do not look correct, start again with a new drawing and do things correctly. Do not just try the same commands over and over on the same drawing.

If the buildings for any reason are defined double up in the terrain model, this problem will also arise. The terrain model will also be bigger than necessary and have redundant data. Keep the terrain model clean!