When modeling meshes, be careful that your surveyor’s contours don’t touch or overlap. If they do, it will create an anomaly in your mesh when you magic wand them.
When you are using the Magic Wand (SHORTCUT = SPACE BAR) to trace contours lines for a mesh, you can adjust the setting that the magic wand uses by going to Options > Magic Wand Settings, here you can increase or decrease the number and accuracy of the points that the magic wand places. Note:
When Site Modelling accurate Cut and Fill Calculations are often what comes between lengthy planning consents and a projects success. Once you have modelled your site make a copy of this and keep it as your existing site. Then modify your mesh according to your project. To get the difference between the two Meshes use
How to create accurate contour lines from an existing ArchiCAD Mesh. Login to www.archicadselect.com > Resources > Tips to download this TIP Sheet. .