Fig. 1. Three-dimensional morphology of the metal surface

Fig. 2. Geometric schematic diagram of the micro-facet

Fig. 3. Masking and shadowing effects of the Blinn model. (a) Shadowing effect; (b) masking effect

Fig. 4. Three models under masking effect (a) Complete passing model; (b) complete masking model; (c) semi-masking and semi-passing model

Fig. 5. Three models under shadowing effect (a) Complete passing model; (b) complete shadowing model; (c) semi-shadowing semi-passing model

Fig. 6. Schematic diagram of the experimental measuring device

Fig. 7. Measured and simulated results of DoP for different materials. (a) Steel with a roughness of 0.40 μm; (b) steel with a roughness of 0.67 μm; (c) copper; (d) aluminum