Cross-Hatch Drawing with Adobe Illustrator
I just stumbled across Saurabh's great tutorial on "How to Convert a Photograph into Abstract Line Art" over at VectorTuts. Quite a nice effect there, but it got me thinking about the fact that there must be an easier way rather than duplicating paths and manually resizing each line to match the underlying image. Here I will show you how you can transform any image into a cross-hatch drawing in minutes.
Create a new document and place the image you want to transform into a cross-hatch drawing (File>Place, or drag and drop from Adobe Bridge).
Select the placed image and choose Object > Live Trace > Tracing Options... I prefer opening this window because it allows me to make changes and see them applied immediately (provided that the "Preview" check box is selected).
Feel free to try out your own options, or copy those shown in the screen shot. Changing the "Blur" options makes the trace smoother. Commit by pressing the Trace button.
With the resulting vector art selected choose Object > Live Trace > Expand. Because now we need to access the newly created paths.
Now you could create your own Patter Swatches (see below for links on how to that) or simply open one of the many, many libraries already available in Adobe Illustrator. I chose: Window > Swatch Libraries > Patterns > Basic Graphics > Basic Graphics_Lines
That's a pretty good collection of line patterns. If you want to see how one is made, simply drag it out of the Swatches Panel onto the Art Board.
(From the Adobe Illustrator CS4 Online Help: Create pattern swatches, Guidelines for constructing pattern tiles).
The magic of the Appearance Panel is that you can apply multiple fills, strokes, and even effects to any selected vector shape. And this is just what I'll use it for. Select any tone with the direct selection tool (the white arrow pointer) in your traced image and choose Select > Same > Fill & Stroke and then click on any pattern in the Swatches Panel (or the secondary Swatches panel which was opened from the Swatch Libraries). Then, within the Appearance Panel, click on the "Add New Fill" button, and choose another pattern. You will see that the two fills now overlap.
For a more painterly effect select any fill and apply an effect such as the "Roughen" effect. Also, you can easily control how many lines you want in your drawing just by tweaking the Scaling Options (double-click on the Scale tool). Try scaling your illustration with the Patterns Option not selected, until you have exactly what you need; then check the Patterns Option and scale the illustration back down to the size you need it. Check out my original Adobe Illustrator file [Zip compressed, 1.1 MB].
You can do this type of illustration with any kind of pattern! Imagine diagonal lines, dots, stars, triangles, colors, *whatever*. Hmm... getting carried away here ;-)