Getting a direct, official "portable" version of Google SketchUp 8 is tricky because Trimble (the current owner) no longer officially supports or distributes this 2010-era software.
SketchUp Free: The modern successor to the "Make" version. It is free for personal use and provides the core tools found in the classic desktop versions. Google Sketchup 8 Portable Free Download
It is important to note that "Google SketchUp 8" is a legacy version released in 2010 Getting a direct, official "portable" version of Google
Volume Calculation: Solid objects could automatically display their volume in the Entity Info panel. Google SketchUp 8 Released - Architect Magazine Getting a direct