It is a PDF file, if you have the PDF software on your computer it should open when you double click the little arrow.
I work in VCadd V6.0, I use it for my job designing large pumping plants. I also use it for all my personal things including things automotive.
I mocked up my tire/wheel combo on VCadd to make sure it would work before I bought the wheels and tires. Nice little tool to have:-)
