If you created a 3D model in Sketchup you can load it in Virtual Surveyor
When working in Sketchup you need to be aware of a number of formats:
kml is a format like the .fly format in Virtual Surveyor. It is a container file that contains some information about point, polyline, view postion, ... It doesn't contain a 3D model but may reference to it
dae or collada is an actual 3D model. You can produce it with Sketchup but you typically need a paying version to save it in this format
kmz is actually a zipped kml file that can also contain a 3D model (.dae).
Loading the 3D model
Although you can load a kml/kmz file directly in Virtual Surveyor it is not an optimal way to load a 3D model. The best way is to load directly the .dae file. You can get the .dae file by saving it in Sketchup (Pro) or unzip the kmz and you'll find the .dae somewhere in the unzipped files directories.
Once you have the dae available you can load it through the following procedure: Supported formats of 3D models