Section 4: Painting and application of textures
Fig. 14: reference paste the reference image in your painting software
Fig. 15: painting masks...mask1.png easy, it's only black and white
Fig. 16: mask2.png another mask...
Maximize the UVW editing window and press "Print scr" ("Stamp" on italian keyboards) to get a screenshot of the monitor in memory. Open your software of choice for tecture creation (Fireworks in my case) and create a new image with a resolution of 2000x2000 pixels and a white background. Press "Ctrl + V" to paste the screenshot in the newly created image, cut away the parts outside the blue square area and rescale the image to fit the 2000x2000 background (Fig. 14). Using this pasted screenshot as a reference we can start painting the masks for our blend material. The first mask will define areas where the white paint is showing. Black areas of the mask will show the white paint (Fig. 15, note the background reference image shown in semi-transparency on the bottom layer). Save the mask as "mask1.png" (or any other 3ds mnax compatible and not destructive image type as TIFF, BMP...).
Let's go back in 3ds max and create 3 standard materials, naming them "white paint", "black paint" and "red paint", changing only the diffuse color to the respective color. We will later change this materials to proper reflective paint materials, but now we just need fast rendering test materials. Create a new "Blend" material and name it "bonnet".
Fig. 17: mask3.png the rising sun!
Fig. 18: mask4.png the black/red gradient on the bonnet
Put "mask1.png" in the "Mask" slot. The material in the first slot ("Material 1") will show up in the black areas of
the mask, while "Material 2" will show up in white areas. This is pretty simple, but the material tree can get quite complex so keep this principle in mind if you start getting confused. Create a new "blend" material in each one of the 2 slots. Name "white" the first material and "black" the second (i couldn't find a better naming, just name things so you can understand at a glance where you are in the material tree).
In the newly created blend material ("Material 1" of the root blend material), which will show in the black areas of mask1.png, we will need white paint areas (sponsors), black paint areas (number 22) and red paint areas as well (the rising sun in the japanese flag), so we need a new mask (Fig. 16) (mask2.png). Put it in the Mask slot. Drag an instance of the white paint in "Material 2" slot: thus the white paint will show in areas defined by black areas in "mask1.png" and white areas of "mask2.png". Create a new Blen material in "Material 1" slot (i named it "red and black"). If you are getting confused help yourself opening the "Material / Map navigator" by clicking on the relative button in the material editor.
In the newly created Blend material, put "mask3.png" (Fig. 17) in the "Mask" slot. Drag an instance of "red piant" in "Material 1" slot and an instance of "black paint" in "Material 2" slot. Go back to the root Blend material and click
on "Material 2" slot ("black"). Put a new mask in the "Mask" slot (Fig. 18, "mask4.png").
Drag an instance of "Red paint" in "Material 1" slot and an instance of "black paint" in "Material 2" slot.
That's it: the principle behind this material, as said, is quite simple, so if you are getting confused feel free to do some experimentation to understand how all this masks and blend materials work together.
Section 5: Creating the shaders
Fig. 19: a test render check the masks...
Fig. 20: paint is finished check the paints and tweak if necessary
Having assigned the "bonnet" material to our bonnet model, fire up a test render which should output something similar to Fig. 19. If the result is the same, we can go on in defining proper paint shaders.
The paint shader are quite simple: i will describe how to build "red paint", the other 2 paint (white and black) are similar,
the main difference being the "diffuse" slot: you can also tweak the various parameters to get particolar effects on the different paints.
So, click on "red paint" in the material editor, and by clicking on the material type button (now "standard") switch to a "Raytrace" material. All your instances in the "bonnet" material will automatically update and reflect the changes you are making. Click on the small "Diffuse" square button and select "Falloff Map" from the list that pops up. Set the Falloff Map type to "Fresnel" and set the "Front" color to 107.0.0 (RGB values) and the "Side" color to 170.114.114. This will make the paint appear a little brighter on the surfaces pointing away from the camera, and quite darker on the surfaces facing the camera.
Put anothe "Fallof Map" (Fresnel type) in the "Reflect" slot, and set the front value to 30.30.30 and the side value to 175.175.175: this way we will have stronger reflections on the surfaces pointing away from the camera, and lighter reflections on surfaces facing it, simulating what's actually happening on real car paints. Go back to the root of the rayrace material and set the color of Specular Highlights to 255.255.255, the level value to 90 and the Glossiness value to 90: this way we will get strong and small highlights. An interesting experiment you can do is to use the "highlight only" blur's plugin in cooperation with a "shellac" material: put the red paint in one slot of the shellac and the
"highlight only" in the other slot: this way you can set up 2 different highlights, simulating the typical car paint "coating".
Create the white and black paint shaders in a similar way and do another test, getting results similar to Fig. 20.