Graphics Reference
In-Depth Information
“If you have small hands, you may want to reduce the thickness of the
ring to make it more comfortable. I have found that a
ringThickness
of
1.2 is less strong, but more comfortable to wear. Experiment with this
value to get a ring that suits you.”
— Anna Kaziunas France
You now have the parametric variables pulled out for easy access at the top
of the code. Now you need to incorporate them into the calculations of the
geometries for the ring.
Calculate the inside radius
To calculate a cylinder, you need the radius value. The radius of a circle
is calculated by dividing the diameter by 2. You can use this information
to calculate the inner band of the ring. However, it also turns out that a
ring fits a little better if you add in a “buffer” of 1mm to your measure-
ment.
If you calculate the inside of the ring by taking the distance across your
finger at the widest point (in mm), adding the buffer of 1mm, then di-
viding by 2, you will get a ring that will fit you reasonably well. It may
require some tweaking, but that is what rapid prototyping with your
MakerBot is all about!
So the formula for calculating the radius of the inside of the ring band is:
r=(ringSize+1)/2
Calculate the outside radius
Next you need to calculate the value for the outside band of our ring. You
will use the formula that we came up with for the inside band of the ring,
and then add the in the thickness of the ring.
The formula for calculating the radius of the outside ring band is
r=(ringSize+1)/2+ringThickness
You can plug this formula into the “outside of ring” and “inside of ring” cyl-
inders as the radius value. You can also use the variable
ringHeight
instead
of the number 6. Your code should now look like this:
//Parametric Variables - change these to modify your ring
ringSize=16.24; // width of your finger
ringThickness=2; // thickness of ring
ringHeight=6; // height of ring
$fn=100; // set the resolution for the model to "high"
difference(){
// outside of ring
