There are some great fan-designed 3D models, many very faithful to the original blueprints, that a snapshot could work quite well for a tabletop battle-grid. Credit always goes to the 3D modeler. I only add missing bits and a bit of colour. Search here for the full series.
This is a 3D Warehouse model by Vincent D. of Main Engineering on the Intrepid Class starship.
One tool that has become very useful is the Slice function on SketchUp, which allows a cutaway view quicker than the deletion method I had been experimenting with. I used it here to isolate the upper and lower levels of Main Engineering. The upper level should fit perfectly over the lower level.