1. A computer-implemented method, comprising: obtaining an indication of a curve; synthesizing at least one element of a pattern specified by a procedural model on the curve from a specified start point of the curve to a specified end point of the curve, wherein the procedural model is configured to synthesize one or more distinct elements according to a set of rules to generate the pattern, and wherein said synthesizing the at least one element of the pattern on the curve overrides at least one of the rules of the procedural model to directly place the at least one element of the pattern on the curve; synthesizing one or more elements of the pattern along the synthesized at least one element on the curve according to the rules of the procedural model; and displaying the synthesized elements.