Per Pixel Painting

What is Per Pixel Painting

Use Per-Pixel mode for high-resolution models (digital art) and low-resolution models (pixel art), where you need maximum compatibility with other environments and where extreme clarity of texture is required.

Note that Depth painting within this mode only supports the real time generation of a normal map, rather than actual painted displacement but, based on this information, a displacement map can be exported as well as a normal map.

The first we’ll talk about is per-pixel painting.
It was introduced into 3DCoat for the first iteration of the v3 cycle. The well-known 3DCoat V2 used Micro Vertex painting. Every vertex had color and coordinates in space, so any kind of displacement was allowed.
However, this approach was limited because it was very difficult to edit mesh with non-quad faces; on that situation projecting patch (vertex faces) to texture resulted in the loss of quality, so it was difficult to import a texture, edit it and export because the after-export texture appeared to be slightly blurred.

Here are the basic points of this technology:

• Painting is performed not over vertices but directly over pixels on the texture. It looks like every pixel on the 2D texture is represented as a point in 3D space.
• Every pixel contains any amount of layers of color, opacity, normal displacement, and glossiness.
• Every layer can be blended with the previous one using common and well-known blending operations for color and displacement.
• Every texture point in 3D space has its neighbors in per-pixel representation. It is important because it allows painting over the model and performing non-local operations like blurring and sharpening with a brush.
• Some operations are performed in 3D space, like painting, filling, and applying curves, and others in 2D projection, like a smudge. All this is transparent to the user.
• Most operations can be performed (optionally) not only on the visible side of an object but on the invisible too, like applying curves, filling, and painting rings, rectangles, and polygons over the surface.
• Exchange with other applications becomes fast, and with no quality loss, you can use 3DCoat at any stage of the pipeline, put a final touch or perform full texturing.
• You can import a normal map and use it as a reference for texture painting. A normal map can be changed, too; you can apply some smoothing (not over seams) or fade some areas.
• Seamless painting and smoothing over texture: This technology can be used for any kind of texturing, low poly or high poly. You can edit textures from 32 x 32 to 8192 x 8192 (if you have 1GB or more of video memory). It can be used in a wide range of applications, from graphics for mobile phones to high-end game projects and films that require huge textures. Also supports tiled, self-intersected, and mirrored textures without any problems.

List of advantages of per pixel painting over micro vertex painting

• Much faster than micro vertex painting.
• Supports tiled, self-intersected, and mirrored UV sets (micro vertex painting supports only non-overlapped texturing).
• Takes less memory than the micro vertex approach.
• Gives good precision of painting without any additional blurring.

The only disadvantage in comparison to micro vertex painting is that per-pixel painting does not support vector displacement, only normal displacement.
Sometimes this makes it an essential point, so we left both approaches per pixel and micro vertex in place.

For example, using micro vertex approach to paint over baked voxel sculptures gives you better results.

Advantages of per-pixel painting over projection painting:

• Possibility to operate pixels on the back side of the model, for example, filling, blurring, and applying overall effects.
• Painting quality does not depend on the distance from the object to the camera.
• More precise painting result; what you see is what you get. The key advantage over usual texture painting in space is the possibility to blur pixels under the brush because every pixel has its neighbors.

PPP now has evolved for displacement painting

So although a tutorial like this will go into painting depth information in microvertex mode and manually painting cracks and shape, instead of using the normal map in PPP mode you can use the depth/height map.

When exporting the low poly mesh from PPP mode, it is a new mesh with different verts.
To export a mesh identical from the one imported and you need to have the exact same model exported but with the new UVs switch Use source position to ON.

3DCoat was updated and the subd patch levels under “texture” on the menu has been renamed to “View > Adjust tessellation”: You can improve visual appearance of mesh displacement using additional tessellation of faces.
Face represented as a grid NxN (weight and height) over every face. Use this options only if you are sure that your video card can support the additional processing.

Adjust tessellation works best painting over with Cube mapping projection, which is the same as triplanar texturing.

Tutorials

How to bake out Displacement Maps: A short tutorial showing how to bake out and export Displacement maps in 3DCoat.