My mesh wont allow me to cut a hole?

Issue description

You have a site mesh and you would like to cut holes to accommodate roads houses etc. When you use the mesh tool to draw the shape of the hole, you end up creating additional roofs instead..

Solution 

Let's go through the steps:

1. Select the existing mesh.

2. Make sure your mesh tool is Active.

3. Draw inside the boundary of the selected mesh.  

4. When you finish your shape you will be given the choice to add new points or create a hole.

Tip: How to remove a hole from a mesh.