A graphics processing system for generating a render output using an input curve defined in a world space includes processing circuitry configured to determine a portion of a canonical curve defined in canonical space that corresponds to the input curve and the transformation needed to map the input curve to the portion of the canonical curve. For sampling points in the world space surrounding the input curve, the processing circuitry is configured to transform the sampling points from the world space to the canonical space using the determined transformation between the world space and the canonical space; and determine, in the canonical space, the closest point on the determined portion of the canonical curve to the transformed sampling point. The system also includes processing circuitry capable of using the determined closest points on the canonical curve for the transformed sampling points in the canonical space when generating a render output.