The paper presents a modification to the existing surface evolution models for predicting channel profiles machined using AJM in brittle and ductile materials. Considering the variation in both the local nozzle standoff distance and the divergence angle of each particle trajectory in the jet plume enabled the modified model to address all the shortcomings of existing models for the prediction of channel profiles machined on inclined and highly-curved surfaces. It was observed that the jet footprint differed on the flat and curved surfaces, becoming wider as the rod diameter decreased. Computational fluid dynamics modeling showed that this was not due solely to the expected conical divergence in the jet, but also due to differences in the erosion caused by secondary impacts of rebounding particles. The model predictions compared well with measured surface profiles machined in flat glass and PMMA targets inclined at 30°, and with axial grooves made in 3 and 5mm diameter glass rods and a 4.72mm PMMA rod (maximum error of approximately 8%). With an appropriate characterization of the footprint, the model is in theory applicable to virtually any target geometry and incident angle.