Creating a 3D Sketch From 2D Plans: Part 2
Adding A Roof To The Guest House

I knew I'd find you here! You just can't get enough of this stuff.

Your guest house needs a pitched roof because:                                         A. City zoning requires it.  -  B. You are tired of shoveling snow off it and you can't get your lazy guests to do it.  -  C. The neighbors say it's ugly and reminds them of a shoebox. Ha Ha

Whatever...Lets add a roof.

This is what a roof looks like in elevation. It's called a Gable Roof because it has triangle shaped ends (more Architectural terms to impress your friends).






Here's a cool shortcut! On the short side draw two diagonal lines, corner to corner, as in the example. Where they intersect is the exact middle of that wall.

If you did that on the 2D elevation it works the same way. The top of the roof is 5 high or half the wall height of 10. On your perspective, draw a vertical line up from the center point (Centerline or C/L). The top of the roof will be half the height of the wall as shown on the elevation. For now make a good guess where that top point is on your perspective and complete the triangle gable end as shown below. 


The section called Shortcuts will help you with an exact way to find the height of the roof.

Remember how we drew the hidden opposite wall in Freehand Sketching? Do the same on your guest house.

Draw converging dashed lines, where they intersect is the hidden inside back corner of the house. I removed the door and windows to see this step better.

Draw the top of the roof.  

Using the super cool  shortcut you learned, find the center of the wall and complete the roof.


This drawing is also known as a Wire Frame. It is similar to what is produced with more advanced Perspective Projection, which will be covered in a future advanced lesson.

Also Computer Aided Design (CAD) programs can produce wire frames from 2D plans. Now you have learned the basics which take the mystery away. If your plans are to go into Design, Architecture or Engineering, this knowledge will be extremely beneficial.

Want more? Part three coming up.

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