“Imperfection is the digital perfection” –unknown
The CG world is so clean and artificial looking that you need to bring in the uglies of the real world to make it look real.
Stuff like dirt, grime, scratches and rust. All of which is covered in this tutorial :)
It took me a couple of weeks of experimenting, but I finally nailed down the perfect method for creating rust in blender (without any extra software)!
Create something awesome using the tutorial? Post it in the comments!
1. Load the startup file and open the reference photo in the UV/Image Editor.
2. In the UV/Image Editor, create a new Image with the settings as seen below.
3. Proceed to Edit Mode and in the UV/Image Editor, change the mode from “View” to “Paint”.
4. Open the Tool Options (T) and change the settings, as seen below.
5. Paint on the areas you want the rust to appear on your model.
6. Save your image in your hard drive to avoid loss of your progress.
7. Proceed to the Material Node Editor and add a Diffuse shader and mix it with the existing node setup.
8. Add an Image Node and use the Rust Mask image as factor input on the Mix Shader.
9. Add the rust texture via the Image Texture node and attach it to the Diffuse shader, as seen below.
10. Attach a Color Ramp Node and modify the colors, as seen below.
11. Continue painting the rust mask texture until you have something like the image below.
12. Add the Normal Map version of the rust texture and use it as a Bump Map, as seen below.
13. Duplicate the Normal Map and use it as input for the paint shaders.
14. Increase the scale of the rust texture by adding the nodes as seen below.
15. Duplicate the Normal Map Texture and disconnect it from the Mapping Node, as seen below.
16. In the UV/Image Editor, using the Rust Mask texture, save it as “Rust_Mask_Streaks”.
17. Reset the paint options to normal, but enable the Strength’s pressure sensitivity and lower the value down, as seen below.
18. Paint the Streaks, as seen below.
19. Proceed to the Material Node Editor and load the Streaks Texture.
20. Attach a MixRGB Node and use the Streaks as Factor input.
21. Using the same Streak texture, connect it as Factor input to the paint’s Mix Shader, as seen below.
22. Attach a ColorRamp Node and control the effect of the streaks, as seen below.
23. Add a new Image Texture and use the Rust Specular Map.
24. Attach a ColorRamp node to the Specular Map.
25. Combine the Specular Map and the Streaks Texture via a Mix RGB Node and set its mode to Multiply, as seen below.
26. Use the Rust Mask texture as the Displacement Input.
27. Add a Scratch Texture and scale it by 4.
28. Invert the colors using a Color Invert Node.
29. Mix the Rust Mask and Scratches with a Mix RGB Node set to Screen, as seen below.
30. Control the final amount of displacement by attaching a Math Node with mode set to Multiply, as seen below.
31. Attach a MixRGB Node to the paint shader that we had previously, as seen below.
32. Use the Scratches texture as Factor input on step #31.