Today's tip of the day by Gavin Goulden focuses on using Polypaint in ZBrush to create skin textures with color spray...
An important part of character creation is having believable skin that renders properly in both high-end and real-time scenarios. With current generation workflows evolving, my process has changed from painting a two-dimensional texture to painting textures right on my high-resolution mesh. This allows me to bake everything out together, and make iterations right at the source rather than manipulating a baked down asset. Most people are familiar with the Polypaint feature within ZBrush, but may not be familiar with how powerful it can be – in this tutorial, I hope to shed some light on that feature and what it could possibly bring to your future projects.
Base Textures with Polypaint
To begin, select a color that is relevant to your character's skin tone and fill your model, then begin marking major landmarks with shades of blue and red. Any tool will do, but I just use Standard with only RGB activated at 100%. Generally, where blood would be closer to the surface will have a stronger red or pink color, with fatter areas and locations that have stubble being slightly blue and green. The key here is subtlety; a small variation can go a long way. Right now, you are working with broad strokes to mark bigger locations. Even at this stage, you could easily bake out a texture to then push further in Photoshop
– using the baked down texture as a starting point or guide.
Mark major areas in your character my defining landmarks using broad strokes with the Polypaint tool
Top tip 1: Adding Detail to Your Skin Texture
Once you have your base colors defined and are happy with them, change your brushstroke to color spray – this will cause the colors that you apply to be varied, similar to changing the spread in the shape dynamics panel in Photoshop. The colors applied will alternate between the primary and secondary colors chosen in your tool, so, if you had black and white, the result will be a mix of black and white dots. At this stage, you are pushing the color variation within your skin but still want to keep the differences subtle, so keep your color selections within the same range. At this point, I work in phases, generally going over the model with bigger strokes that help break up the surface and then refining it more as I go along.
Use color spray and work in passes to bring more detail and life to your character's skin texture
Top tip 2: Baking Down Your Textures
Chances are, if this asset is for games, you will need to export the colors you have created in a format that can be used as a texture. If you already have UVs on your model that are to your liking, you can simply convert Polypaint to Texture. This will create an image that you can then export, flip vertically, and use as a Diffuse texture. If not, you can generate UVs, follow the same step, and export the texture along with your model. Once you have a low poly asset with proper UVs, you can then transfer the color information to your game asset.
Generate UVs for your model and export the color map that you have created in a format that is friendly to game assets
Polypaint is a great tool for laying down base textures as well as creating fully detailed color maps for your characters
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