From 3D Software to Photoshop

1. Export a PDF File from Sketchup (or any other 3D software). Preferably, use the Hidden Line Style to get a clean image
   
   
   
   
2. Open the PDF in PS 
3. Paint with Bucket faces differentiating light and shadow
   
   
   
   
4. Draw Concrete texture with fine Brush.  Remember to do this step in a New Layer
   
   
   
   
5. Fill gaps with Clone Stamp and eliminate what you do not need with Eraser
6. Add sky and elements with the same color using Bucket and Brush with 100% hardness. If needed, use the wand or other Selection tools. Remember to do this step in a New Layer.
   
   
   
   
7. Add concrete texture and transform it pressing Ctrl to follow the perspective
   
   
   
   
   
8. Eliminate parts you do not need using Invert Selections and deleting from Layer
   
   
   
   
9. Add to missing places with Clone Stamp
10. Lower Brightness in places with shadows
    
    
    
    
11. Outline edges with Brush at 0% hardness (black color and then lower Opacity)
    
    
    
    
12. Draw Clouds in a New Layer with fine Brush. Remember to do this step in a New Layer
    
    
    
    
13. Add trees and plants with Brush (you can download them from a lot of pages including us) Remember to do this step in a New Layer
    
    
    
    
14. Draw people with fine Brush, use Shift for straight lines and then paint inside with Bucket (New Layer)
15. Add people shadow: Ctrl+J to duplicate layer & Ctrl+U to lower Illumination. Last step is to lower Opacity
    
    
    
    
16. Add color with Bucket and draw texture with fine Brush to do metal elements (New Layer)
    
    
    
    
17. Add color with Bucket to grass areas (New Layer)
    
    
    
    
18. Draw Grass texture with fine Brush (New Layer)
    
    
    
    
19. Fill gaps with Clone Stamp and eliminate what you do not need with Eraser
    
    
    
    
20. Do not forget to put your name on it!
    
    
    
    

The Final Result