Hey, I'm trying to create a spiky circular curve, but can't think of the best way to do this. Think cartoon sun with spiky edge that a four year old would draw. But with many spikes...and it has to have perfectly symmetrical spikes... and expressions are the devil's playthings.
I tried drawing one out with grid snap and then bending it with a lattice and mirroring, but I didn't like the outcome. Spikes were getting distorted. Wish there was a way to extrude a 2d curve along another 2d curve. or...wait.....is there?
Create a NURBS circle with an even number of CVs--as many as you want there to be points on your sun. Switch to Edit Point selection (NOT CV selection), and select every other point.
IMPORTANT: the seam of the curve should NOT be selected. If you have the seam (i.e. the very first point) selected the next step will most likely cause an error!
Now go to Edit Curves -> Insert Knot. Set the options to 'At selection' 'Set multiplicity' to '3'. Click the Insert button. Now, each curve point you had selected will be capable of being a sharp point.
Now comes the tricky part. Switch to CV selection mode, and you'll notice there are now 3 CVs in between each of the newly-sharpened points. Carefully select them all. If you have a really dense curve, this will be a pain to do. (You could use an expression to do it quickly and easily, you know, but, "devil's playthings" and all...)
Once you have all these 'soft' CVs selection, just switch to the scale tool and scale them down. You should end up with the nice spiky sun you're after.
A quicker solution would be to create the curve in Adobe Illustrator and import it, if you can.