This paper presents an online personalised non-photorealistic rendering (NPR) technique for 3D models generated from interactively sketched input. This technique has been integrated into a sketch-based modelling system. It lets users interact with computers by drawing naturally, without specifying the number, order, or direction of strokes. After sketches are interpreted as 3D objects, they can be rendered with personalised drawing styles so that the reconstructed 3D model can be presented in a sketchy style similar in appearance to what have been drawn for the 3D model. This technique captures the user's drawing style without using template or prior knowledge of the sketching style. The personalised rendering style can be applied to both visible and initially invisible geometry. The rendering strokes are intelligently selected from the input sketches and mapped to edges of the 3D object. In addition, non-geometric information such as surface textures can be added to the recognised object in different sketching modes. This will integrate sketch-based incremental 3D modelling and NPR into conceptual design.