Some initial sketches, developing the idea of simulating natural line drawing.
This type of hatching is popular in contemporary illustration – here I’m emulating this ‘distracted’ line, where small errors can become amplified as each layer is drawn with the last as a guide. Adding imperfection will be a large part of the sketches generated for Dada (an irony perhaps given the hard work Ad is doing to ensure Dada’s movement is accurate!).
Programmatically, the concept and implementation is really simple:
- Begin with a set of points selected with random offsets within a range
- Duplicate the points and offset each by a constant plus a random amount
- Modulate the offsets using a sine wave to smooth out the peaks
- Every so often, correct the offsets by referring to the original points
The script also chooses to look ahead to the next or previous point (x coordinate) on the preceding line at random intervals, which causes a wandering of peaks across the page.
Here is the same sketch again, however this time the points are drawn by interpolating between the x coordinates of the points and using this midpoint as an anchor for drawing a quadratic bezier curve through all points. The result is a more natural line, though to draw curves with Dada we’ll probably have to compute the curve (to a certain resolution) using a series of small line segments.
The other issue is overlapping lines. In this simulation I can fill white over the previous line within the shape of the new line, effectively blocking out any overlap. To draw this with only a pen or pencil, it will be necessary to calculate all intersections and then remove the overlapping line segments, breaking the line segment into several lines segments. If Dada could go back with an eraser and rub out the overlaps that could also be a nice touch!