All that stuff you forgot from geometry
You can throw on top of these expressions several more functions to make things behave a bit differently. By simply trying out sine, cosine and tangent (abbreviated sin, cos and tan in the Filter Factory), you can generate some wild effects. Again, we're simply going to build upon the expressions we created in the previous section. You can do this in one of several ways. First, you can simply enclose the whole expression inside the parentheses in the expression sin(). So the example for the R channel above would look like this:

sin(src(cnv(ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(6)), cnv(ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(7)),0))

Remember the extra parentheses at the beginning and end. Now, I don't particularly like the way this makes the image look. So the other way you can do this is to take your expression and insert sin (or cos or tan) functions throughout it. We could do it:

src(sin(cnv(ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(6))), sin(cnv(ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(7))),0)

or we could place the functions randomly throughout the expression, remembering to use parentheses properly, as in:

src(cnv(sin(ctl(0)),cos(ctl(0)),tan(ctl(0)),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(0),ctl(6)), cnv(ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(1),ctl(7)),0)

You can see examples of the effects below.

Three ways to apply a sin function to a convolve function.

 

One important thing to keep in mind is that the Filter Factory preview is not too terribly likely to represent the final look of your image. You might see some great banding and noise effects in the preview, only to come up with flat posterization when you apply the filter. There's really no way to say when it's going to be accurate, so you'll need a little extra patience to get just the right look. Now, once you've created your filter, as I showed you in Part 1, your previews will become much more accurate.