Well if I had to produce something like that this would be my approach:
1. Output the plan as a PDF.
2. Open the PDF plan in Photoshop (Rasterizing it). And put this on its own seperate layer and make the background transperant (ie. delete all the white).
3. Do a plan view rendering of the building with a cut plan at 1200mm which includes the flooring but disable the shadows. Save this as a JPEG.
4. Open this JPEG into PS, size to match the plan and place on a layer below the plan.
5. Render a second plan view but this time add another cut plane just above the floor and exclude the floor from the picture. Save this as a JPEG.
6. Open this JPEG into PS, size to match plan, make the background transparent and place on a layer between the JPEG with the floor and the plan.
7. Now run a drop shadow effect on the JPEG with no floor.
8. Lastly add a very subtle drop shadow effect on the bottom JPEG.
No doubt there'll be several was to acheive this.
)
