In this tutorial, I will explain how to draw a floor plan in SketchUp accurately and to scale from measurements taken on site of an existing space. I will demonstrate the technique I use with measurements I took of the floor plan from my own house.
In the last two tutorials, I explained how I draw the basic floor plan from the image on the assessor’s site and then print it to scale so I can use it as the basis for my measurements on site, which saves me time because I don’t have to figure out where to start or the overall scale of my drawing when I’m with the client.
Step by Step Instructions
The method that I’m about to explain certainly isn’t the only way to draw a 2D floor plan in SketchUp. Some designers prefer to draw on top of the sketch drawing. I know that my drawing probably isn’t scaled accurately enough for me to use it as a reference, so I just work from the dimensions.
But first I should probably explain how I measure. I start by using my trusty laser tool to measure the overall dimensions of the rooms. Then I go back and add details for all of the openings and any other elements. For windows and doors, I dimension to the opening from the nearest wall or opening. I also (usually) record the exterior width of the casing. I note the sill height and header height for windows.
I try to work in a systematic way through each room, but I have to admit that I can easily get distracted while I’m measuring. Sometimes I also use an app on my iPad that lets me take photos of a wall and add dimensions and notes to the elevation.
If you want to follow along, here are the dimensions of the interior walls in a format that might be a little bit easier to read. You can click the image to make it bigger or save it to your computer.
Let’s get started. I’m going to open up the 2D floor plan that I created for the initial drawing and switch to the top view (Camera – Standard Views – Top) and then switch to Parallel Projection.
Then I’m going to switch the Shaded drawing style because I find it a little bit easier to work with. Go to Windows – Styles and select whichever drawing style you like best for drawing in 2D.
Whether I dimension the entire house or just a room, I always pick one corner and work my way out. For this drawing, I’m going to use the bottom left corner, which happens to be my living room. The living room spans the entire width of the house, so I’m going verify that the measurement in my SketchUp drawing matches the dimension I recorded.
I selected the Tape Measure tool, click on the inside edge of the left wall and dragged the mouse to the inside edge of the right-hand wall. The measurement is 27′ and my field dimension is 27′ 2.75″ so I am going to adjust the width of the room.
First, I hit Escape to exit the tape measure tool. Then I’m going to Zoom Extents so I can see my entire plan. I’m going to use the Select tool (the arrow) and click on a point that is just to the left of the top right wall of my house and then drag a selection box over everything to the right.
After the second click, I can see that the selected walls are highlighted blue.
Now, I’m going to adjust the width of the living room by the 2.75″ difference. Click on the Move tool in either your top toolbar or the large toolset to select it. Then click on the bottom right corner of the garage wall. Start dragging the cursor to the right, making sure that the red or green dotted guideline is visible. Without clicking again, type 2.75″ and hit enter. Use the tape measure tool to verify the new dimension is correct.
Basically, we’re stretching the horizontal wall that makes up the bottom of the living room by 2.75″ by moving all of the walls to the right. You can use this same technique to resize many different shapes within SketchUp.
Before we move on, I should explain that I have made the basic assumption that because the house is a simple rectangular shape, the width of the living room is the correct width of the entire structure. I also want to delete a portion of the center wall that was shown on the assessor’s site but isn’t there in real life.
At this point, it’s really easy to delete walls. All I’m going to do is use the Pencil tool to draw two lines to create a separate segment in that long wall and then use the Eraser tool to delete it. In SketchUp, faces (the gray shaded part) are created by closed loops of lines (edges). When you draw a line through another line, the point where they intersect breaks the line up into segments that you can manipulate independently.
After creating the wall segment, I click the Eraser tool and then click on each of the long edges of the segment to erase them. The face will disappear automatically because it can’t exist without the edges.
And, here’s what it should look like…
Before we move on to drawing the interior walls, I’m going to create a group from the exterior walls. In SketchUp, edges and faces are “sticky”, which means that if you draw two faces or 3D objects that are touching each other, they will stick to each other when you try to move them. I want the ability to work with my interior walls separately from the exterior walls, so I’m going to group them separately.
To select elements easily in SketchUp, you can single, double or triple click. If you single click on a surface or edge, only that surface or edge will be selected. If you double click on an edge, the edge and any adjoining faces will also be selected. If you double click on a face, the face and all adjoining edges will be selected. If you triple click on any surface or edge, all surfaces and edges that are connected to each other will be selected. I’m going to triple click on one of the edges in my plan to select everything in the plan.
I can tell that everything is selected because all of the edges are blue. If I zoom in on the face of the wall, I can tell it’s selected because it is covered in blue dots.
With the edges and face selected, I’m going to right-click somewhere on the face and select Make Group from the menu that pops up.
I click Zoom Extents so I can see the entire plan again. Now, when I click on any of the edges or the face of the walls, all of the edges turn blue but there are no dotted lines on the face. I also see a blue box surrounding all of the walls in the group.
I am going to begin laying out the interior walls by using guidelines created with the tape measure tool. First, I’ll establish the depth of the living room, which is 12’9.25″. I select the tape measure tool and click the bottom interior wall of the living room and drag my mouse up. As I drag, I type in the value and hit enter. This establishes a guideline for the wall.
This wall thickness is 5.5″. I’m going to use the tape measure tool to establish another guideline, but this time I’m going to click the first guideline, drag up and enter 5.5 for my length.
I’m going to use the rectangle tool to add the interior wall for the living room. I click on the Rectangle tool to activate it. Then I click at the intersection of the top guideline and the interior edge of the left wall and then click again on the intersection of the bottom guideline and the interior edge of the right wall.
You may be wondering, “Why go to the bother of using guidelines? Why not just use the pencil tool to draw lines?” One of the biggest mistakes I see students make is drawing crooked lines. When I establish a guideline at a specific distance from an edge that I know I drew aligned to either the green or the red axis, I know for sure that any lines I draw snapped to that guideline will also be aligned to that axis. In other words, I know they’ll be straight.
It’s really important to make sure that all of your lines in an orthographic drawing are exactly that – orthographic or perpendicular to each other at 90-degree angles. It’s really easy in SketchUp to draw a line that’s just a little bit off. You may not notice it at first, but later it will cause you lots of problems. If you use this method from the beginning, you’ll be assured that all of your lines are accurate and straight.
So here is my new wall. You can delete the guidelines once you’re done with them by using the Eraser tool and clicking on them one by one. But, it’s easier to go to Edit and Delete Guides, which will delete all of the guidelines in the drawing at once.
I’m going to repeat this process for the rest of my interior walls. As you draw your walls, you may find that you need to adjust the exterior walls before you go any further. To open the group for editing, double-click on any edge or face within the group. You’ll see that everything outside of the group is lighter or grayed out and everything inside the group can now be selected and edited. You can also add to the group while it’s open. To close the group, double-click on any point outside of it.
Here’s what my plan looked like when I opened the exterior wall group to edit the two walls that make up the dining room…
You will also notice as you draw interior walls, that the edges of the walls will create new faces for not only the walls but also within the rooms. Delete these faces for now. Single click on each face and then hit the delete key or go to Edit – Delete.
When I’m all finished adding my interior walls using my guideline and rectangle method, I end up with this…
Every time I draw a plan from field measurements, there’s always a little tweaking that needs to happen. In this case, I had to experiment with the wall thicknesses to make sure all of the interior dimensions were correct. I could have taken measurements at certain points to more accurately establish the wall thicknesses, especially since this is an older house with plaster walls, but I’m not too concerned with that right now. If this were a client’s house, I would go back and verify the wall thicknesses at a subsequent time.
My next step is to clean up all of the wall intersections by deleting the lines in between each of the wall faces. I won’t be able to delete the intersections where the interior walls meet the exterior walls because they don’t actually share those edges because the exterior walls are grouped.
I won’t be able to delete these…
Finally (for this tutorial anyway), I’m going to group the interior walls using the same method I described for the exterior walls. I end up with three separate groups for the interior walls.
In the next installment of this tutorial, I will explain how you can easily add window and door openings to your plan and create 2D symbols for door swings and window glazing.