Drawing instructions
Ellipse shape
Place the ellipse tool on the TactiPad and hold it at the finger fitters positions.
Draw along the inner contour for the ellipse shape.
Finding the centre position.
As long as you create two crossing lines that are symmetrical, they will pass the centre position. Symmetrical here means each line is a diameter line, from opposing angle positions, not necessary the lines of the longest and shortest diagonals.
When connecting the pushpins at 0 and 180 and also those at 90 and 270 degrees, you obtain the longest and shortest (orthogonal) diameters.
The full lines will cross the centre position.
Be aware, when placing all four pushpins at the outside and then lifting the tool might cause the pushpins fall out. To avoid this, place two pushpins at the inner side a 0 and 90 degrees and two along the outside at 180 and 270 degrees. By moving the tool slightly upwards off from the pushpins you can safely lift the tool.
Placing the ellipse on a pre-determined centre position
The open space at the inside of the ellipse does not make it easy to place the ellipse centre on a pre-defined position. You have to create support lines.
We might need to develop an insertion tool for positioning.
Dome
Instead of drawing the full contour you can draw parts or a dashed section of the ellipse. Dashed lines are applied to indicate invisible lines of 3D figures.
For a dome, orient the longest diagonal of the ellipse horizontally on the TactiPad. Draw the lower part of the contour as a solid line and the top half as a dashed line. Now you have the bottom section of a dome. The dashed section represents the invisible part of the dome.
This 3D figure can be completed by placing the top (T) somewhere above the dashed section of the contour and providing two lines from the position T to both ends of the virtual diagonal.
While the push pins are still there, the line for the diagonal at the bottom should be dashed as well because this line is not visible.
Fantasy 1
Create an ellipse and place a pushpin somewhere along the inner side and rotate the ellipse and draw it again.
Choose a different position for the pushpin. Repeat this a few times, for an unexpected result.
Fantasy 2
Combine the ellipse with the triangle or square and fit the shapes into each other.