If you're brand new to SketchUp, one of the first things you'll notice is that your "walls" are paper-thin. Consider what happens when you build the following:
Deleting the top face (step 3) of a form you've push/pulled into existence results in super-thin, single-surface walls. That's fine if you're building Japanese shōji, but for many applications, you'll want to model your walls with a thickness. The easiest way to go about doing this is to use the Offset tool. You can activate it by choosing Tools > Offset from the menu bar or by clicking on its tool icon. If you haven't set up your own keyboard shortcuts yet, you can switch to the Offset tool by pressing F on your keyboard.
Here's how to use Offset to create walls that look thick:
- Start with any face in your SketchUp model.
- Activate the Offset tool (choose one of the methods listed above for doing so).
- Click once on your face (the one in your model).
- Move your mouse (don't drag) toward the center of your face.
- Click again when the offset edges you're creating are the right distance from the original perimeter of your face.
- If you want to be precise, type an offset distance (such as 6in or 15cm) on your keyboard and press Enter (This Help Center article has more information about entering precise dimensions in SketchUp, as does this video).
- Switch to the Push/Pull tool by pressing P on your keyboard.
- Click between the two sets of edges on your face to push/pull it into a 3D form.
- Click again to stop push/pulling.
Want to learn more about Offset? Check out this video.