Using Divide to Build Stair Stringers
Using the Tape Measure (T) tool described on page 281, measure the right angle formed between the midpoint of the concrete step and the midpoint of the landing's frame. You need to know both the vertical and horizontal distances spanned by the stairs. So click the top edge of the concrete step, and then press the up arrow to lock the cursor's movement to SketchUp 3D models" href="/3d-models/introducing-the-blue-axis.html">the blue axis. Then move the cursor over to the midpoint of the landing's frame. As you can see in Figure 7-25, a tooltip appears displaying the distance. For the model in this section, that distance is 6' 9 1/4". (If your measurements vary by an inch or two, don't worry about it. Follow these steps and SketchUp makes the stairs to fit.) You might as well click to place a guide marking the midpoint; it may come in handy later. To measure the horizontal distance, click the edge of the landing's frame, and press the right arrow to lock the cursor's movement to the red axis. Then click the midpoint of the concrete stone. Tape Measure reports the horizontal distance is 9' 2".
Figure 7-25:
Use the Tape Measure tool to find the vertical and horizontal distances the stairs span. The tooltip on the Tape Measure shows the vertical distance.
Figure 7-25:
Use the Tape Measure tool to find the vertical and horizontal distances the stairs span. The tooltip on the Tape Measure shows the vertical distance.
Armed with these two measurements, the vertical and horizontal distance, you can create your stairs. SketchUp does the rest of the calculations courtesy of the Divide command. It's easier to build the steps first and then place them in the model, so begin your drawing in front of the concrete step and the landing.
1. Using the Rectangle tool, begin to draw a rectangle. Type 9'2,4', and then press Enter (Return).
Your measurements provided the horizontal distance the stairs must travel: 9 feet, 2 inches. You want the stairs to be as wide as the landing: 4 feet.
2. With the Select (space bar) tool, right-click the front edge and choose Divide from the shortcut menu. Then move the cursor left or right to adjust the division. Click when the tooltip says "11 segments".
SketchUp displays red squares to mark the division of the edge. As you move the cursor to the right, SketchUp displays fewer segments; move it to the left, and the tooltip shows more segments. Below the number of segments, you see the Length and a measurement in inches. The number showing will be the run for your stairs and roughly the size of the stair tread. As explained in the box on page 261, you want your run to be between 9 and 11 inches.
3. Choose the Line (L) tool, and then move it along the divided edge. When you see a tooltip that says "Endpoint", draw a perpendicular line to the opposite edge.
Your line creates a new face in the rectangle that looks suspiciously like a stair tread.
4. Continue to draw lines at the endpoints to divide the large rectangle into 11 faces, as shown in Figure 7-26.
If you have trouble drawing a line on axis, press the left arrow to lock the cursor's movement to the green axis.
When you're finished, you're done with the horizontal work. The next steps go vertical.
Figure 7-26:
Remember, only draw lines at the endpoints. Don't be fooled by the midpoints on the edge. When you're finished, you've divided the rectangle into 11 stair treads.
Figure 7-26:
Remember, only draw lines at the endpoints. Don't be fooled by the midpoints on the edge. When you're finished, you've divided the rectangle into 11 stair treads.
5. With the Line (L) tool, start to draw an edge from the front right corner of the rectangle along the blue axis. Type the height for the stairs.
Press and release the up arrow to lock the line to the blue axis. The height for the model in the figures is 6'9.25. Your mileage may vary.
6. With the Select tool, right-click the new vertical edge, and then choose Divide from the pop-up menu. Type 11 and press Enter.
This one's easy: you already know that you have 11 steps and need to measure 11 vertical positions. The Divide command does the work of figuring out just how much rise is required. The line divided into 11 segments serves as your measuring stick.
7. With Push/Pull (P), click the face closest to the divided vertical edge, and then pull the face up to the top of the line.
Your top stair step snaps into place.
8. Continue to pull the rest of the steps into position, as shown Figure 7-27.
At this point, your rectangle is Push/Pulled into a shape that looks remarkably like a set of stairs.
Figure 7-27:
For some models these quick-and-dirty stairs might be enough. In some cases you may prefer simplicity over realism. Stairs like these provide some design information without using a lot of computer resources.
Figure 7-27:
For some models these quick-and-dirty stairs might be enough. In some cases you may prefer simplicity over realism. Stairs like these provide some design information without using a lot of computer resources.
9. Clean up your stairs by erasing the extra edges in the model, as shown in Figure 7-28. If necessary reverse the faces (right-click ^ Reverse Face).
Make sure to erase the extra edges on the back of the stairs that were created during the Push/Pull operation.
At this stage the stairs are the right dimensions to drop in place—4 feet wide. If you want, go ahead and use the Move tool to put them temporarily in position. When you're finished checking them out, bring the stairs back out in front of the landing. For some models where you want to limit the detail, quick-and-dirty stairs like these may be fine. For this model, you'll create a few more stair details. If you take another look at the stairs in Figure 7-1, you see that they're made from two stringers and 11 treads for the steps. The stringers are made from 2-inch lumber. In the next steps, you'll trim your stair stringer down to size and turn it into a component.
1. Using the Move (M) tool, click the face of the stairs, and then begin to push back (Figure 7-29). Press the right arrow key to lock the movement to the green axis. Type 3'10 and then press Enter (Return on a Mac).
The stairs were 4 feet wide. Trimming them down by 3 feet 10 inches creates a stair stringer that's 2 inches wide. If you have any leftover edges or faces that aren't part of the string, clean them up with the Eraser (E).
Figure 7-28:
You can drag to delete the extra edges in the stairs. If you accidentally erase the wrong edge, one of the faces may disappear. In that case, just press Ctrl+Z (C-Z), and then try again.
Figure 7-28:
You can drag to delete the extra edges in the stairs. If you accidentally erase the wrong edge, one of the faces may disappear. In that case, just press Ctrl+Z (C-Z), and then try again.
Note: Lumber used for construction is usually available either rough or dressed. Dressed lumber is planed so its actual dimensions are less than the nominal dimensions. So far in this chapter, most of the lumber was planed. For the stringers, you're specifying rough lumber with actual dimensions that are close to the nominal 2 inches. The stringers are hidden from view and touch, so rough lumber doesn't present an aesthetic problem. The stairs can benefit from the extra strength of thicker lumber, too.
2. With the Line (L) tool, hover over the top stringer's first inside corner as shown in Figure 7-30. Move on the red axis to the edge and click the edge.
An inference line appears as you move the cursor back to the edge.
3. Move to the bottom edge of the stringer, and find an inference from the bottom inside corner, as shown in Figure 7-30. Click the bottom edge of the stringer.
A diagonal line marks the angle for the bottom edge of your stringer. Get out the power saw.
Figure 7-29:
Use the Move (M) tool to turn your 4-foot-wide stairs into a 2-inch-wide stair stringer. Here, the moving face is constrained to motion along the green axis.
Figure 7-29:
Use the Move (M) tool to turn your 4-foot-wide stairs into a 2-inch-wide stair stringer. Here, the moving face is constrained to motion along the green axis.
Figure 7-30:
Draw a diagonal line across the bottom of the stair stringer. After you remove the triangular portion by using the Push/Pull tool, you have a model of a typical wooden stair stringer.
Figure 7-30:
Draw a diagonal line across the bottom of the stair stringer. After you remove the triangular portion by using the Push/Pull tool, you have a model of a typical wooden stair stringer.
4. With Push/Pull (P), click the triangular front face of the stringer, and then click the back edge.
The excess material that was attached to the stringer disappears. It now looks more like a real piece of lumber sawn into a stringer. And you don't even end up with any sawdust on the ground. If you have any leftover edges or faces that aren't part of the string, clean them up with the Eraser (E).
5. Triple-click the stringer and press G. In the Create Component window, for the name, type stringer and for the description, type 2-inch stair stringer. Then choose Create.
You've created a new stringer component. For these stairs you need two stringers. Wider stairs often use more stringers to provide support in the middle of the tread.
6. With the Move (M) tool, click the bottom-back corner of the stringer. Then click the midpoint on the back of the concrete step.
The stringer is installed. The bottom edge is aligned with the midpoint of the concrete step. The top edge is aligned with the midpoint of the landing's frame. The back edge of the stringer is flush with the back edge of the landing.
7. Still using the Move tool, press Ctrl (Option) to switch to copy mode. Click the bottom-front corner of the stringer, and then click the midpoint on the front of the concrete step.
A new stringer is positioned on the other side of the concrete step.
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