The most likely problem is that the sections you have added are on a different layer to the original drawing. In SheetCam layers are completely independent of each other.
In SheetCam, go to View->layer tool. The layer tool will show all of the layers in your drawing. Move the layer tool to one side of the screen so you can see the drawing. If you click on a layer that layer will be highlighted on the drawing.
Your cad package should have a method of hiding layers. Hide the main drawing layer. Now select everything else that should be on that layer and move it to the right layer.
Les |