Create

   • Click 2 points + 'Escape' to create a simple unit curve...
   • or click 3 points to create a unit curve with a free end decoration.
   • You can draw multiple unit curves in each layer.
   • Click on "Add layer" to add a new layer.
   • Adjust the height of the layer by clicking 'g' in the side view
    or perspective view, and dragging the orange point up or down.
    'Escape' to abort the edit, 'Enter' to accept it.
   • Select a unit curve and press 'h' to add a vertical line at the end of the biarc.
   • Press 'f' to fill all the faces.

Edit

   • Control points are marked in black. Move them to adjust the curve.
   • To edit a unit curve at a specific layer, select the layer first.
   • Select a unit curve and press 'r' to change the position of the PRC point of the biarc.
   • Select a unit curve and press 'd' to add a decoration to the lower part of the biarc.
   • Select a unit curve and press 'delete' to delete it.

View

   • Press '1', '2', '3' to switch between the top, side and perspective views.
   • Press 'h' show or hide this dialog.