Building the new design
In part I we explained that by drawing a circle and extruding it, you can build a complete model (part). In the image below, you can see two cylinders on top of each other. The model is represented as a cross-section.
In this cross-section, two cylinders with different diameters are attached. The reason one cylinder has a different diameter than the other is because we do not want our body to be pushed all the way into the mouthpiece, so it acts as a stop. The distance between the fipple (the end of the blade) and the tone holes determine the intonation (along with the diameter and the shape of the tone hole), so we need a consistent build. This end stop will help us be consistent in our build.
And now, for the hardest part of the design; how do you go from a perfect circle (the beginning of the chamber) to an ovale shape (the beginning od the windway)? The answer: software. We are drawing a circle on the tube that we showed. Next, we are drawing a new plane, perpendicular and at a certain distance from the tube end. On that plane, we draw an ellipse. In addition, guide curves are drawn, to let the software know how we want to achieve the transition. Next, we are creating a lofted extrude from the circle to the ellipse, with the guide curves as the…yes, you guessed it; the guide.
In above picture you can see the guide curves (purple) and the initial circle (sketch 10) and the ellipse at the other end. On e guide curve is a straight line, the other is a spline (based on a number of variable curves).
Let’s see how it looks like when we extrude a solid from the circle to the ellips, using the guide curves:
By applying ‘zebra-stripes’ to the preview, we can check for consistency and symmetry. By turning the model, we can check every angle.
View from above. The model is completely symmetrical. In this model, you can also see that the actual mouthpiece is slightly smaller than the rest of the chamber.
By applying and confirming the preview, we create a solid. Next step is to create the cuts like the windway, the chamber, and the window, leaving room for the blade. However before we do this, some corrections are made to the outside of the model.
Next is the windway. By drawing a rectangle at the beginning of the mouth piece and extruding it over a length of 45.5mm, we create a cut that will mark the end of the windway.