Making a decent volocano...

[waldronate]

The gradient tool in Wilbur draws slopes. One setting for Type is "Radial", which draws a cone with the value at the outer edge equal to the value "Low" in the gradient toolbar and the center equal to the value "High" in the gradient toolbar when you click and drag. Using the same tool but with the center value equal to a lower altitude and the operation to "Min" (minimum), the gradient will drop out the center of the cone. Most of the rest of the operations (noise, incise flow, precipiton erosion, and exponentiation) are the standard prettying operations I tend to use in Wilbur. The only difference here is the use of morphological erode to get rid of the little spikes of noise that the operations leave.

Wilbur really needs a median filter, but I haven't gotten around to that. The Morphological Dilate and Erode filters are similar, being a local max and min operation rather than a local median operation. A better algorithm would have a patterning element rather than just using a 3x3 square neighborhood, but you get what you get.

Maybe this GIF will help. You get two seconds per frame, but it does loop.