| 
    The finished Screenshot. | 
  
     | 
    The floor plan - scanned from a book. | 
  
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    Rotate the plan until it is oriented the way you want it. | 
  
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    Use Scale to compress the image vertically. This compression creates the illusion that the scene is being viewed from the side. | 
  
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    Use Crop and Image Size to frame the part of the plan that will become the drawing. | 
  
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    Draw a vertical line - make it as long as the height of the wall. Copy and paste the line, placing a copy at each corner on the floor plan. | 
  
     | 
    Use the Polygonal Lasso Tool and the Fill command to draw surfaces. | 
That's the main 
  stuff. A few other tips....
  - Surface Textures - I usually draw them straight on, then use the Shear or 
  Distort commands to match them to the surface.
  - Name your layers - some of the screenshots had close to 100 layers, very difficult 
  to keep track of without descriptive names.
  - Figures are just drawn freehand.
  
  Please let me know if you have any questions, or if I can make something clearer.
  -Jon