In this tutorial, we will use the versatile utility shader to generate random colors for the sprinkles on a donut. We will then use a variety of color shaders to further adjust the colors of the sprinkles.

A simplified scene file can be downloaded here.

Standard Surface

• Start off by creating a standard_surface shader and rename the shader 'Sprinkles'. Assign it to the sprinkles geometry.

Utility Shader - Color Mode

• Create a utility shader and connect it to the base_color parameter of a standard_surface shader. We will use the object_mode of the utility shader to add random colors to the sprinkles. This mode uses the name of the shapes to compute the color.
• We don't want any shading from the utility shader as we are already using the standard_surface, so change the shade_mode to flat. Flat renders the model as a pure, solid, flatly lit and shaded color.

_{Utility Map connected to standard_surface.base_color}

Random - Seed

We can use the random shader to create variations of color for our sprinkles.

• Create a random shader and connect it to the base_color of the standard_surface shader. Connect the utility shader to the input_color of the random shader.

• Change the seed parameter number. You should notice that the color of the sprinkles randomly changes.

_{Random's seed parameter animated (utility shader set to object mode)}

Composite

We can also use the composite shader to mix in another color using a blend mode.

• Delete the random shader and create a composite shader. Connect it to the diffuse_color parameter of the standard_surface shader. Connect the utility shader to Input A of the composite shader.
• Change the operation parameter of the composite shader to multiply and change the Input B color to orange. You should see that the colors of the sprinkles now have an orange tint to them.

_{Color of sprinkles tinted with an orange color using the multiply operation of the composite shader}

_{Change B color to orange and Operation to 'multiply'}

Color Convert

Another way to change the colors of the sprinkles is to use a color_convert shader.

• Delete the composite shader and create a color_convert shader. Connect it to the diffuse_color parameter of the standard_surface shader. Connect the utility shader to the input parameter of the composite shader.
• Try changing the color space to see the effect it has on the color of the sprinkles. In this case, it was changed to xyY.

_{Color space converted to xyY}

Color Correct

Once you are happy with the general colors of the sprinkles, you can use a color_correct shader to further fine-tune their appearance.

• Create a color_correct shader and connect it to the diffuse_color parameter of the standard_surface shader. Connect the utility shader to the input parameter of the color_correct shader. You can adjust the exposure and multiply parameters, for example, to add more variation to the color values.

_{Fine-tune the colors using a color_correct shader}

That concludes this tutorial. Have a go at experimenting with some of the other color correct shaders to create some different variations of color.