How to Generate Wall Elevations and Cross Sections in Autocad from Floor Plans
Houses have four elevations. We could call them Front, Back, Right Side, Left Side. I like to orient them to the compass: North, South, East and West. On our house West is the view to the water and East is the view to the road.
We will use the first floor plan on the right and then the second story plan. |
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Step 1 is make a new layer: EAST and give it a color. Select EAST as the default layer. Turn on Floor1. Also toggle on ortho to force autocad to draw either up and down or left or right. This will make all lines straight. Also set snap to 2 if you have been drawing with snap turned on. Otherwise, use object snap.
Now draw a horizontal line below your main floor plan far enough that you will be able to draw all of your floors and roof lines. Label this line "Top of Floor". This is your reference for all horizontal lines.
Now locate the corners of the house that will show in the elevation and accurately draw vertical lines for each corner that will be in the elevation. I have indicated these lines with the red circles. |  |
Now in the next image I have extended the vertical lines to meet the horizontal top of floor line. I do this with the extend line command.
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Then I turn on the second story plan to see if I need to add any more corners or windows. In this case I don't need to add anything for this elevation except I do want to keep a line on the fireplace because I will need to eventually add a chimney.
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Next Step. Offset the top of floor line by however high your first floor ceiling height is. In my case, 9' or 108". That represents the bottom of the ceiling. Offset this line up 12" to represent the floor joist area. This new line is the top of your second floor. Then offset top of second floor line the height of the second floor. In my case, 8' or 96".
To arrive at the height of my windows and doors I offset the top of floor line 80' which is standard. to get a garage door height I use an offset of 7' or 84". |  |
In the drawing to the right I have trimmed the garage door to the 7' height and the entry door to the 80" height. I have also trimmed the tops of the two 1st story bedroom windows. I now go to the second story and offset the floor 80 inches to get the tops of the 2nd story windows. I will then offset the top of the windows down 48" since my bedroom windows are 48" tall. My entry windows are 60" tall so I will offset their top down 60" and trim.
Now trim out the unnecessary lines and you have the drawing to the far right.
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This is the developing elevation. I have filleted the corners of windows. The garage door top was found by offsettig the top of floor line 7' (84"). The window tops are offset 80" from top of floor. If a window is 48" high then I offset the top of window line (which was 80" from floor) down 48" Then you trim out the many lines and this is what you get.
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To get roof drawings we need to go to the adjacent elevation. In this case that means the NORTH ELEVATION. Set North as the draw layer and make a vertical line to the right of the floor plan, far enough away to be able to construct an elevation (probably around 40'.
Top of floor line is circled red.
Blue circles denote lines you need to show the corners of the house. |  |
Here we extend the critical corners and any other details like windows or doors to the top of floor line at far right.
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Offset the top of floor line for first floor the distance from floor to ceiling (9 feet in my house). Offset the ceiling height up 12" to accommodate floor joists. That makes top of floor line for second floor (shown with red circle). Offset that line the height of the ceiling (8 feet for me) and you now have the top of ceiling or top of plate height which we will use for defining the roof.
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We also need to locate the chimney location which is shown to the right.
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Now select all of the lines in the North Elevation and rotate them as shown here.
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With ortho and snap on I drag the North Elevation down to match top of floor lines of both elevations.
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And here I have trimmed out the lines to make the first and second story lines more obvious.
My roof pitch is 5/12. This means the roof rises 5 inches for every foot of run. I begin by drawing a line from the left end of the ceiling line to the right 12', then draw up 5' then enter C Enter to close the triangle formed.
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Now I offset the hypoteneus of the triangle 6 inches. I also offset the wall 24" to make a 24" overhang for the roof. I at this point erase the 5' vertical line and the 12' horizontal line of the original triangle.
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Now carefully fillet to form the end of the rafter tail.
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Select the rafter tail (the three lines contained in the red circle) and mirror them along the plate line midpoint. This gives you two sets of rafters.
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Fillet the tops of the rafters together. This locates the top most ridge. Chimneys need to be a minimum of 24" above the closest roof within 10'. So draw a line from the ridge through the chimney boundary lines. Then offset up 24" to get the top of the chimney.
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Offset the top roof line to create a shingle layer. Fillet out the chimney to its final shape.
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Now select a rafter (crossing box in the location of the red circle). Copy the roof using the intersection of the wall and top of plate as your pick point. Make two copies as shown to the right.
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Trim out the extra lines and the elevation will look like this.
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Now we extend the roof lines from the North Elevation across the front of the East Elevation.
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Select extension lines and move them to the East Elevation.
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Here we offset the sides of the house 24" to get a 24" roof overhang. Overhang roof lines are circled.
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These extension lines from North elevation show the top extent of our roof.
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This shows trimming of the roofs to accurately show roof height and roof overhang. Now we have to still find the height of the garage roof.
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Here is clean up editing of the above projection lines to establish a more final look.
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To find the garage roof height I had to take the depth of the building from roof overhang to roof overhang (34'.) Then half of that is 17'. The math is roof height = distance to center from edge times 5. Then I offset the horizontal bottom of the roof up that distance to get the top of the roof.
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Last step is to locate the chimney. I find these lines from the floor plan and project them down for the sides of the chimney and from the North elevation to establish the top of the chimney.
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And this is what we get when we do the final trim.
All done except for labeling window and door heights and showing the height of the building with a dimension. We also want to attach a label like EAST ELEVATION and a scale like SCALE: 1/8" = 1' |  |
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