How to Add Floors to a Building Model in Google SketchUp 8
Adding a second (and third, and fourth) floor to your model in Google SketchUp isn’t as hard as it may seem. The key is to think of each level as a separate “tray” consisting of interior walls, a floor surface, and the ceiling of the level below.
You model each floor as an individual group, making it easier to hide, edit, and move. For the same reasons, you also make the exterior walls a separate group; they act kind of like a “box” into which your floor levels stack.
Making groups to keep things separate
The edges and faces that make up your exterior walls should already be enclosed in a group by themselves. If they’re not, taking the time to set things up now will save you hours of headache later.
Provided your exterior walls are already a group, the next step is to turn the rest of your first floor’s geometry into another group. This is how you do just that:
Select the floor and interior walls of the first level.
Triple-click a face on any interior wall to select everything that’s attached to it.
Make a group by choosing Edit, Make Group from the menu bar.
Drawing the next floor
Modeling each new floor directly on top of the one underneath guarantees that everything in your building lines up. Here’s how you add a second floor to the house model:
Trace the inside perimeter of the exterior wall to create a new face.
You can use the Line tool to do this. Keep in mind that this works only if everything you touch is already part of another group; if it isn’t, your new edges stick to your existing ones, and your model becomes very, very messy.
Push/Pull your new face into a thick slab.
A reasonable ceiling-to-floor distance between levels for houses is about a foot. You can figure yours out with a tape measure and a calculator.
Draw the interior walls of the new floor.
This is just like drawing the first floor. Switch to the Top view (Camera, Standard Views, Top) and then use the Tape Measure, Eraser, and Line tools to draft your floorplan.
Push/Pull your interior walls to the correct height.
That’s 8 feet, in this example.
Group together your interior walls, your floor, and the ceiling of the level below.
If your upper floor isn’t bigger or smaller than your lower floor, pull up your exterior walls to match your interior ones.
Here, you’re extending the box that holds your floor trays up another level. Follow these steps:
Edit your exterior wall group by double-clicking it with the Select tool.
Use Push/Pull to extrude it up.
Exit (stop editing) the group by clicking somewhere off to the side of your model.