Let's see now how to add a dirty map through the Vertex Colors tool and how to bake it to an image texture; such a texture map can be useful for the creation of the shaders (which we'll see in the next chapter).
To do this, we are going to use an already set .blend file:
- Start Blender and open the
Gidiosaurus_baking_normals.blendfile; save it asGidiosaurus_baking_dirty.blend. - Put the mouse pointer in the 3D view and press the Z key twice to switch into Solid viewport shading mode; click on the 14th scene layer to enable the visibility of the Gidiosaurus_detailing object.
Let's first go with the creation of the Vertex Colors layer:
- In the Outliner, select the Gidiosaurus_detailing object and then click on the mode button in the 3D viewport toolbar to select the Vertex Paint mode:
Selecting the Vertex Paint mode item
- Now, click on the Paint item in the 3D viewport toolbar and from the menu, select the Dirty Vertex Colors item; the Gidiosaurus mesh, first filled with a plain white color, gets shaded in grayscale tones:
Using the Dirty Vertex Colors tool
- Expand the last operation panel at the bottom of the Tool Shelf and press Ctrl+click on the Dirt Angle slot to enter the value 90°; the grayscale shading on the mesh gets a lot more darker and contrasted:
Tweaking the settings for the Dirty Vertex Colors tool
- Go back in Object Mode and then move to the Material window, where the Body material is already assigned to the high resolution mesh. Scroll down the panel to reach the Shading subpanel and enable the Shadeless item; then, reach down the Options subpanel and enable the Vertex Color Paint item:
The Shadeless and the Vertex Color Paint items
To understand the effect of the items we enabled in the Material window, just switch to the Rendered viewport shading mode; the mesh surface is self-illuminating and showing the dirty Vertex Colors layer:
The Dirty Vertex Colors layer visualized in the Rendered preview
Note that the Shadeless item is not actually mandatory for the baking, but is only required to see the object in the Rendered viewport shading mode as in the previous screenshot.
- Also, enable the 4th scene layer (Shift+left-click) and in the Outliner window, select the Gidiosaurus_for_baking object. Go to the Object Data window to be sure that the UVMap_norm layer is the active one and then go to the Render window and scroll down to the bottom, to the Bake subpanel; click on the Bake Mode slot to select the Textures item from the pop-up menu:
Baking the Dirty Vertex Colors layer to Textures
- With the Gidiosaurus_for_baking object still selected, enter Edit Mode and select all the vertices; in the UV/Image Editor window, add a new 3072 x 3072 blank image renamed as
vcol. - Go out of Edit Mode and in the Outliner, select the Gidiosaurus_detailing object; then, Shift-select the Gidiosaurus_for_baking object and go to the Bake subpanel under the Render window to click on the Bake button:
The final baked "vcol.png" image map
- Save the baked image as
vcol.pnginto thetexture_makingfolder. - Enable the 3rd scene layer, select the Armor_detailing object, and repeat the procedure; save the baked image as
vcol2.pngin thetexture_makingfolder and also save the file:
The baked vertex color layer for the Armor
The Vertex Colors tool can add a color to each vertex of the mesh, so it's actually possible to paint an object without the need for an image texture; the denser the mesh, the better this works.
The Dirty Vertex Colors tool uses the proximity and the depth of folds and creases on the mesh surface to calculate grayscale values to be assigned to the vertices; thanks to the Vertex Color Paint item, enabled in the Material window, this grayscale shows up in the rendering and so it's also possible to bake it into an image.