Freehand Drawing Tool (keyboard shortcut: D)
This tool, called the Freehand Drawing tool, is used to draw curves directly, as you would with a pen or pencil on paper. To draw a path with the Freehand Drawing tool, click on a starting point and drag all the way around the contour of the path you wish to create. The path is finished when you release the mouse button. If there are any sharp points on the contour of the path, it is good to start at one of these. If you want to add other sharp points, pause in your drawing until a white square with a blue outline appears there, then continue.
The point where you started the path is marked with a solid blue square. If you finish your path inside this square, it will create a closed path. (It will turn red to indicate that you have hit it.) If you finish the path outside the square, it will create an open path.
The path that is created by this tool may not perfectly follow the contour you drew. In order to make freehand paths easier to edit and use less memory, it attempts to create a curve using as few points as possible that follows the contour as closely as possible. It is also designed to smooth out the jitters that are common in freehand drawing with the mouse. It is not always perfect, but the imperfections can be fixed with the Reshaping tool.
Tweaking curves after drawing
After you draw a curve with the freehand tool, a slider appears at the bottom of the Properties panel allowing you to adjust the smoothing tolerance.
Adjusting the tolerance of a newly drawn freehand path.
If you don’t think the curve you got is accurate enough to what you actually drew, drag the slider to the left. This will reduce the tolerance of the smoothing, resulting in more points that follow the original drawn curve more accurately. But the additional points might make the path more jaggy, and a little harder to edit with the reshaping tool.
If you think the curve you got isn’t smooth enough, or contains more points than you think it needs, you can drag the slider to the right. This will reduce the number of points, making the path smoother and easier to reshape, but it might be a little less accurate to what you actually drew.
The same freehand drawn path, with different tolerance settings applied.
You can make multiple adjustments to the slider, which re-centers itself after each use. When you deselect the path, or edit it manually, the Tolerance slider goes away. The raw drawing data is only saved as long as the slider is visible, so it is not possible to make this type of adjustment to the curve later.