Wed 1 Apr, 2009
An Intermediate Google SketchUp Tutorial – Part 5A
Click Here To Comment/Comments (1) Filed under: SketchUpTags: Cabriole, Legs, SketchUp, Tutorial
In this installment we are going to learn to draw cabriole legs. Cabriole legs go back as far as the ancient Greeks and Chinese but are more commonly associated with Queen Anne, Chippendale and Louis XV period furniture. They are characterized by the “S” shape where the top of the leg bows outward and the bottom bows inward. The foot can be anything from a slipper like shape to a ball and claw. The cabriole leg is generally completed with a knee brace for dressing. The finished set of cabriole legs at left are textured with a cherry grain.
In order to take this tutorial you need to download Tall Cabriole Leg Tutorial Part A SketchUp file; click on the latter hyperlink. There are two entry points for this tutorial. The first entry point includes drawing the leg outlines using the Cubic Bezier Curve tool. Those of you who need more practice with Bezier curves can begin the tutorial there. Though I don’t walk you through the details of drawing the leg outline, I do provide you with the sequence of steps and some helpful hints. You can refer to Part 4 for information on using the Cubic Bezier Curve tool. If you feel you have had enough of drawing Bezier curves but want to know how to draw a cabriole leg you can start at the second entry point, where I have done the hard work for you.
Wherever you enter this tutorial, be mindful that if you make unrecoverable mistakes you can always download the model again, so don’t hesitate to experiment. That is an important part of the learning process.
First Entry Point
Open the model Tall Cabriole Leg Tutorial downloaded previously. Make sure Layer0 is active and the Visible box is checked for layers Grid, Template and Z-Leg. The Visible box for layers Pad Outline and Upper Leg Outline should be un-checked. Your drawing area and Layers box should look like that at right. The .jpg used as our template is already on the Template layer and registered to the grid. However, it is almost impossible to get registration and size perfect, so I have provide the actual dimensions for reference.
Start by drawing all the straight lines first. If the straight lines in the Template do not look registered to a grid line correctly, place the line on the grid as per the dimensions supplied. The pad will be rotated with the Follow Me tool later, so only draw one half of it. Complete the Pad Outline before drawing the curves of the leg. When the straight lines and Pad Outline are completed your picture should look like that at left. Notice that in this picture Layer0 is active and Z-Leg is visible. No other layer is visible. The straight lines and the Pad Outline are all on Layer0. Also note that the Pad Outline has a face. You will likely have to coax this face by drawing one or two straight lines to make it appear and then erase those lines. If that doesn’t work check to see that the ends of the curve on the left side of the pad connect with the straight lines of the pad. Use the Bezier curve Edit tool to move those points until they do and then coax the face again.
When the Pad Outline and straight lines are drawn as shown above, un-check the Visible box for Z-Leg. With the Select tool select only the Pad Outline, right click and Make Component. Name the component Pad Outline. You will get a warning message “A component with that name already exists…..”. See picture at right (Notice that only the Pad Outline has been selected with the Select tool.). I have generated this component and supplied it in the model. If you are sure you have correctly drawn the Pad Outline click Yes. You have now replaced my drawing of Pad Outline component with yours. Since I have also placed a copy of Pad Outline component on layer Pad Outline, which is now your component, you can delete yours on Layer0. Now make layer Pad Outline visible and check to see that yours appears, then un-check layer Visible box for Pad Outline and you are left with just the straight lines for the Upper Leg outline.
Make layer Template visible again. Now use the Cubic Bezier Curve tool to finish outlining the upper leg. Make sure that the horizontal line at the bottom edge of the leg runs along the Red axis and is parallel to, and 25 7/8″ down from, the upper horizontal edge. Also make sure that the ends of the curved portions connect with the straight lines. Use the Bezier curve Edit tool to correct it if they are not. You will have to coax the face again, and this time you may need to add six or more lines. But once it appears, delete the lines you added. With the Select tool select the entire Upper Leg Outline, right click and make component. Click Create and you will get a warning as before. Your drawing area should look like that at left. If you are confident you have correctly drawn the Upper Leg Outline component click Yes. As before, you have replaced my component with yours, including the one on layer Upper Leg Outline. Delete the one selected on Layer0. Make layer Upper Leg Outline visible to be sure it is still there, though it is now your drawing. Proceed to Second Entry Point.
Second Entry Point
OK, we are all together again; the brave souls that came through the First Entry Point and you wimps who started at the Second Entry Point. Open the SketchUp model Tall Cabriole Leg Tutorial downloaded previously (or your version). Make sure layer0 is active, Upper Leg Outline is visible and the other layers are not visible. Also choose Front and ISO views. From the Components/Select/In Model box drag in two more Upper Leg Outline components. You now have three in the drawing area; one on layer Upper Leg Outline and two on Layer0. Rotate and align one on Layer0 with the one that exists on layer Upper Leg Outline as shown at right. Notice I have turned on viewing of the axis.
Un-check the Visible box for layer Upper Leg Outline. With the second Upper Leg Outline residing on Layer0, the one that has not been aligned, place it where the Upper Leg outline and layer Upper Leg Outline was before making it invisible. See picture at left.
Select one of the Upper Leg Outline components and Explode it. With the Push/Pull tool pull the face in each direction 6″, so that it ends up 12″ long. Triple click, right click and Make Group.
Select the other component, Explode it and extend it in each direction 6″ with the Push/Pull tool. Do not Make Group, leave it as primitives. Select the Group created above and Explode it. Now, triple click on a surface to select all primitives and choose Edit/Intersect/Intersect with model. Be patient and wait for the blue outlines to disappear. This may take a few seconds. Your picture should look like that at right. Notice the unwanted lines that need to be hidden at some point. This can be done with the Eraser tool and the Ctrl key. Leave hiding lines until the end of clean-up.
Use the Eraser tool to clean up the Upper Leg. To aid clean-up select View/Hidden Geometry. Rotate the drawing to avoid erasing geometry you want to keep.
After erasing unwanted geometry, de-select View/Hidden Geometry so that the lines which need to be hidden is more obvious. With the Eraser tool and the Ctrl key carefully hide these lines. Rotate all around the Upper Leg to be sure you get all of them. Zoom in close to avoid erasing a defining line.
Some lines may appear not to hide. Zoom in real close and you will see that you may have to rebuild a small section. Erase a few lines, and then look for end points to tie together in rectangles or triangles. When you have re-built the area hide the lines you added. This problem shows up frequently with Bezier curve models. Patience and detail are the only solution. But I have never run into one that can’t be repaired.
Your picture should now look like that at left above. Select this Upper Leg and create a component called Upper Leg and place it on a new layer called Upper Leg. Un-check layer Upper Leg Visible box and check Pad Outline Visible box.
In order to operate on the Pad Outline with the Follow Me tool we need a path to follow. See the picture at right for details on creating the path. Select the Circle tool and check the VCB to be sure that the sides parameter is 24, if not type 24s and enter. Start with the center at Point A. Place the second point along the Red axis and slightly beyond the Pad Outline; Point B in the picture at right. Delete the face of the circle so there is only a perimeter. The construction line in the picture at left is there simply to emphasis that the second point of the circle is along the Red axis; you do not have to draw this construction line.
Select the Pad Outline component and Explode. In the Layers drop down box place the exploded path on Layer0 (it is currently on Pad Outline). With the Follow Me tool extrude the Pad. The Follow Me tool is finicky. I suggest starting very close to Point B, but still on the face of the Pad Outline, and moving along the Red axis until reaching Point B. When the shape is formed release the mouse. You may have to triple click the Pad with the Select tool and right click to Reverse Faces if the color is wrong. You may also have to use the Ctrl key (add) and triple click the bottom of the Pad to include it in the selection. I am not sure why this is sometimes necessary given we extruded a single face, but for some reason it may be.
Create a diameter line on the top of the Pad, preferably along the Red (or Green) axis. Select the entire Pad by triple clicking with the Select tool (include the bottom if necessary with the use of the Ctrl key). See the picture at left above. Do not include the path. Now create a component called Pad and place it on a new layer called Pad. Delete the path circle.
Finally, we have an Upper Leg and a Pad shown right. The Pad is not in the correct place, and even if it were the bottom of the Upper Leg is square and the Pad is round. In Part 5B we will place the Pad and smoothly transition the Upper Leg to the Pad to create the slipper look. Save your work. This is where we will begin Part 5B. Stay tuned.
nagog says:
I am interested in your tutorial(s) on Cabriole Legs please provide mailing and payment instructions Thanks