Imported model tracing question

I use Sketchup mostly to source models for my architectural models created in Chief Architect. I need to calculate volume for some of my projects and I am looking for an easier method than doing my calcs on paper. I can export my 3d house model to .SKP format and I am wondering about how difficult it would be to trace a building similar to the image shown?

The roof overhangs would be excluded from the volume so the forms are somewhat simplified. The areas of most concern are the roof planes where they do not make simple geometric shapes.

If you get to make your volumes as a solid group, the Entity info will give you the volume without you needing to calculate it.
Just trace the main outlines of the house and create the surfaces from them.

Thanks. I will start experimenting to see if it is faster than pencil an paper.

Be sure it is.