Elliptical wooden table leg, 140 cm high, 70 cm wide, and 72 cm high.
I would like to divide this oval shape (140 cm x 70 cm, 4 cm thick) into 20 approximately equal segments. I also want to know at which angles the individual 20 boards need to be cut. Could someone help me figure out the easiest way to draw this and determine the angles at which the boards should be cut? the planks are standing vertical.
hi @huib
Welcome to the forum.
I would do something like this:
- work on a quarter of the ellipse because of symmetry
- I wouldn’t do the cut at the summits of the ellipse but symmetrically vs them
- draw 7 lines from the center that will be the cut lines
- set symmetry constraint bewteen lines 1 and 2 and lines 6 and 7
- draw 6 construction lines between the end point of the seven lines
- set equal constraint to the length of the 6 construction lines
- you can now measure the angles and cut the panels
[Edit] video added
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I think the parameters are to create relatively equal width planks with which to make the oval base and to help calculate the angle cuts needed for each plank?
If you are intending to make the ellipse from planks.
You probably want them close to equal widths, and none of the angles to be over 90 degrees. This will allow strapping to be applied and tightened whilst the glue sets. If any angle is over 90 the planks will pop out under compression.
If this is roughly what you had in mind, I will do in more detail.
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20 wood pieces divided and combined for a LEG? Mind Blown!
Yes, this is exactly what I mean! If you would like to do that, I’d greatly appreciate it. Thanks in advance!
Hi
I will list out the approach used.
Having done a quick drawing to your dimensions, I would be inclined to used a lot more planks. Even with 6 in each quadrant you will have a lot of material to remove when smoothing, as each plank is about 140mm width.
Here is a simplified process for which will need you to draw more segment lines to suit your need.
Step1: Draw the Ellipse and enter the size dimensions you want (this locks the size).
Step2: Starting at the bottom draw straight lines allowing auto snap to the Ellipse curve (as many as you need).
Step3: Now lock the end point as shown. ‘Screen1’ picture shows result of step1 to 3.
Step4: Shift Select all of the straight segment lines and set = ‘Equal’ attribute. This will make all the segment lines the same length to fit around the curve. See ‘Screen2’
Step5: Now lock all of the incident points around the curve, where the straight lines intersect. This will stop things moving in the next step. See ‘Screen3’
Step6: Now draw short straight lines from these points away from the Ellipse curve and set them to be Tangent to the Ellipse curve using attributes.
Step7: Using the auto drawing guides, Draw lines towards the axis that are perpendicular to the tangent lines. Which ever line the auto guides are using as a reference is highlighted (glows). Step 6 and 7 are illustrated on Screen4
Step8: You now have the necessary lines to measure cut angles. See ‘Screen5’
You will need to play around with offset lines and extending line lengths to extend outside of the ellipse curve.
There is a much easier way than this, using single offset lines.
Steps 1, 2, 3, 4 are the same.
Step5: Click offset edge single tool, and select all of the straight segment lines.
Step6: Set the offset inwards by the distance you want. (Step5&6 picture)
Shapr3d will automatically size the faces of the new line.
Step7: Add two lines from the origin to each of the quadrant axis intersections, and use TRIM tool to trim the ends of the new offset line. (Step7 picture)
Step8: Now add short single lines between inner offset line and outer original to create the plank cross-section shapes. (Step8 picture)
That should give you all you need to get measurements and make templates.
If using 10 planks per quarter, I think I would make the long axis of the Ellipse 1% over size to allow for sanding to shape.
Have fun!
Thank you very much, it helps a lot!
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