An essential element in creating an interior design or architectural model is building the walls with their correct thickness or width. We go through all the steps in our SketchUp training courses.
If you have bought the SketchUp Pro version for around $600 you’ll be able to import the CAD plans and use them as a guide when building the walls. But if you only have the free Make version of SketchUp you’ll have to draw the building footprint first using either the Line tool or the Rectangle tool, using a sketch on paper as a guide, or possibly an imported JPEG image.
Either way it may help to go to the Camera drop-down menu and choose Standard View and Top from the list. If you’re using the Line tool make sure that you draw along the Red and Green axes – these correspond to the X and Y axes of a CAD program like Autocad or VectorWorks.
Now we wish to offset the wall thickness, or widths. These will vary according to the age of the building and its construction, but common external wall values in Australia are as follows. Measurements from internal to external have 10mm plaster plus 90mm timber stud with a 40mm cavity followed by 110mm brick, making a total of 250mm. Single brick will be 110mm, whilst double-brick will be 270mm.
Next we select the Offset tool or hit F on your keyboard, then click on the building footprint and pull your cursor gently inwards towards the centre of the shape. Note the value in the bottom right Measurements field; type 250 and hit the Enter key. Alternatively you can type .25m to override the millimeters and hit Enter. Note also that if you have inside room measurements (for example in an interior design context) you’d offset outwards, but if you have the outside building measurements (in an architectural setting) you’d offset inwards. Click and drag your mouse-wheel (or hit O) to orbit around the model – it’s a good idea to do this continually as you model, to ensure you’re not extruding along the wrong plane.
To create the wall height we select the Push/Pull tool (or hit P), click on the wall offset section and pull gently upwards. We then type in the wall height, for example 2800 (or 2.8m) and hit Enter to complete the command. It’s a good idea to select the floor and hit the Delete key on your keyboard to get rid of the inner shape. Then triple-click on the walls with the Selection tool and right-click to select Make Group. In SketchUp we always create groups as we go in order to keep objects separate from each other.
Many useful tips and techniques can be found at the SketchUp website. And see many examples of our own clients’ work on our Facebook page.
Other related SketchUp Blog Posts:

• SketchUp background
• SketchUp introduction
• SketchUp modeling
• SketchUp contours
• SketchUp workspace