Sketch up Photoshop dimension/resolution correlation


Im new in 3D, I need to do matte painting in speculative architecture for my project,
at the moment I don’t understand how can the resolution of the 3D model
surface match later on in PS with image texture.
I can setup the resolution due to " Make Unique Texture" option in Sketch up, however I haven’t got any clue when I create the dimension of 3d model in meter according to the picture which I will use for texturing later on in PS, which it appears in cm and the picture usually bigger than the 3D model, therefore the image even, if I scale it down, don’t match with shape. In other words is there any link between meter(in PS cm) and resolution, that make it easier estimate when I design the face of the 3D model according to dimension and resolution of PS.