Shape Brush Roundness needs to detect Pen Shaft Rotation. Only certain Wacom pens have this feature. Otherwise, it should be an option that the shape can change with Initial Direction.

When you draw with a real pencil, you can change the way you hold the pencil in order to alter the way you create shapes. By changing the angle, you can make new strokes.

However, with the DP10 method, you can't change the angle except for doing it manually by moving a slider. This is unnatural for an artist. To constantly have to stop drawing and manually alter a setting that is capable of being detected by software is ridiculously inconvenient.

I don't know if it's outside of DP10's capability to create lines where the angle of the shape brush changes dynamically, but this is just another example of 'almost useful, but not quite there.'