- What is an RGB/RGBA Mask?
References
The RGB Mask (correctly known as RGBA Mask - red, green, blue - and A for alpha) is a simple image that maps out each part of your multiplier(see: What is a multiplier?) to a particular pattern channel in the game's Create-A-Style Tool. The image on the left shows how the UV map of a table has been mapped into three different pattern channels for the game.
They are incredibly easy to make. The mask maps out which pattern channel in the game applies to which part iof the mesh. Red links to the first or only pattern channel being used by the mesh, blue to the second, green to the third, and the alpha channel to the fourth when available (not all creations offer the full four patterns - the majority of objects offer only three).
What if my mesh is only one or two colours?
For 1-pattern objects: - make the RGB mask all red
For 2-pattern objects: - make the main part of the object red, and the second part green
For 3-pattern objects: - make the main part red, the second largest part green, and the last part blue
(4-colour meshes are discussed below)
Why do some EA RGB masks have other colours?
When painting in pure red, green and blue colours, we’re actually painting white on the RGB channels of the image (and anyone who has made Sim patterns will already know about these). The game is using the underlying channels as shown in Photoshop extract below. Each channel links to a pattern slot in the CAST tool. If you paint white directly into any of these channel layers, the main picture will show pure red, green or blue.
However, for 4-colour creations, the alpha channel is used, but unlike the RGB channels, this channel has no attached 'colour' to it and so won't show on the main image in the same way as the RGB channels did. The colour for the alpha channel (provided it is not pure red, green or blue) can be ANY colour just to show where the alpha area lies. The RGBA mask on the right has an orange shade showing where white is on the alpha. The colour used is immaterial provided that the alpha channel itself is white. EA have been known to use orange, pink and yellow colours.
So I just add an extra colour if I want four colours?
No. If only it were that easy! To use all four pattern channels, the creation you're cloning must already have all 4 channels available (most windows and doors do, many nursery objects, and a few other object types are creeping in that use four colours too. If the item you're cloning has only three enabled pattern channels in Workshop, then adding a fourth alpha layer will have no effect.
I've seen RGB masks made of pinks and yellows - what are these?
Some creation types (walls and floors for example, as well as clothing) can blend patterns so that changing one pattern causes a shift change in all the others too. One example is the dirt-wallpapers that came with World Adventures, where the brick block is red on the first channel, but the dirt on the green channel is YELLOW. Yellow merges the red and green channels, allowing the two channels to blend. This is not available by default in standard objects and if the object you're cloning uses the first three channels as red, green and blue, then this is what you need to use too. There are rare objects that do blend (a one-tile round EA table for example) but these have a special blending property set in the internal files that we cannot access in Workshop currently.
For full details on creating RGB/RGBA masks for objects, see Object Creation Part 2: Object Textures
See also: Sims 3 Wiki RGBA Mask page
Referenced from:
- Resource Sims 3 Textures - Basics
- Resource DDS Images
- Resource I’ve imported my textures but some parts of my object appear white in the 3D view - why?
- Resource How do I create a Sims 3 object?
