Hello and thanks for all the answers by now.

I'm writing this OpenStudio measure that needs the area of each surface and subsurface. What I can find in OpenStudio is just Point3d of each PlanarSurface's vertices and there is nothing I can find about the area. I think that might be because EnergyPlus only gets the X, Y, Z coordinates. So I was thinking about writing a method for calculating the areas or try to match the coordinates with the ones in the SketchUp and then use the area calculated by SketchUp.

This brings me into two questions. First one is that is there any way to get the area directly from OpenStudio? and if the answer is no, Is there any better way to find out the matching SketchUp Face to the OpenStudio PlanarSurface or do I have to find them by coordinates?

Thank you for your time