Creating a 3D Sketch From 2D Plans: Part 3
Adding An Addition To The Guesthouse

You've spent a whole bunch of money on a guesthouse; but, nobody visits for very long, and if they do they can sleep on the blow-up mattress.

You want to use this house for you, not guests! How about a home theater? Yea, or maybe a music studio, hobby room, sport room or fort. Now we're talking!

How do I do that? You ask...Here's how. From the original plan let's add more space to one room.

We now have an L shaped building and we can use the original perspective and build on it.

The new elevations look like this. They look a little confusing, don't they? This is one reason people have trouble understanding construction plans, another good reason to view a building plan in 3D.

In this design the door is placed slightly to the right of the centerline of the building elevation. The first thing we are going to do is to see how close to the centerline you placed the front door on the perspective drawing created earlier. Use your centering shortcut. I was pretty close. If you were too far to the left or right, erase your door and relocate it so it looks like my example. This centerline point is where we will start building the addition.

Just to the left of the door draw in the first wall. Its top and bottom are going to converge to the right vanishing point because it's going the same direction as the side of the house, meaning they are in the same plane with each other. They share the same vanishing point. Look at the new side elevation for reference to see how far the wall comes out from the existing house. Make your best guess. You are getting good at this.

Start drawing the new wall coming out from the end of the house. Same vanishing point, right!

Now you can finish the front of the addition by converging lines from the top and bottom of the wall next to the door.

I'm going to test you again (oh no, another test). No sweat! Using what you know from drawing the side of the existing house; find the center and draw the gable end over the addition. How did you do? It should look close to the example.

You passed with flying colors. (I don't know what that means. I heard some old guy say it once.)

Converge a line from the top of the new gable roof back to the existing roof.

Where it intersects is where the Valley (where two roofs meet) starts. Draw a line from that point down to the intersection of the addition wall and existing house. This completes the valley.

By now the design is easier to understand. Draw in the new sliding door and you've got your new addition.

This is a plan view of the roof you just drew.

If you want, place a piece of tracing paper over your wire frame perspective and add some finishing touches. Don't forget some landscaping.

A completed thumbnail sketch could be used to show off your concept. What a great tool.

You deserve a big pat on your back! This 3 part lesson was the toughest of all. If you made it thru this far you know more about 3D perspective drawing than most of the people working in the design field.

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