Decals

Decals in the context of DECALmachine, are mostly - but not necessarily - single-polygon-meshes with a specific Decal material applied. The material determines the type of a decal, of which there are currently 4:

  • Simple - normal mapped + parallax, 1 material component
  • Subset - normal mapped + parallax, 2 material components
  • Panel - normal mapped, up to 3 material components
  • Info - color mapped

DecalTypes 3 simple, subset, panel and info decals, each 1 polygon

These so called mesh-decals are an alternative approach to detail texturing.
But unlike actual texturing, detailing using Decals, does not require any UVs being present and is extremely flexible, due to it being noncommittal, non-destructive and object based.

Note

This is not to be confused with mixing textures and materials via multiple uv channels on the same objects, for which term Decal is also sometimes used.

Parallax

Parallax is a shader effect, that by utilizing an UV offset, creates the illusion of depth on flat geometry.

Parallax

Note

How well parallax works depends on the angle you are looking at it from.
Also, parallax works better for some types of detail than others.
Going into the surface, works surprisingly well. Going above, not so much.
A single level of depth works better than multiple levels.

Orthographic Views and Cameras

The parallax effect will not work properly in an orthographic viewport.
However, you can still render it perfectly, when using an orthographic camera.

Mirror

One huge advantage of mesh decals being objects - as opposed to just textures, or part of a texture - is that you can use modifiers on them.
The Mirror modifier especially comes to mind. Arrays can also be useful at times.

To setup the mirror modifier for decals, you need to tell it to mirror the UVs as well - in most cases that would be the Flip U option, in some rare ones it's Flip V, it depends on how the decal is layed out.
Without the UVs being mirrored, the parallax effect will be distorted and text will be reversed and unreadable.

In addition and with a Normal Transfer mod being present in the stack, make sure any mirror modifier is positioned before it. Normal Transfers should always be at the end.

A great way to mirror decals and do all the above automatically, is by using the Mirror(and Un-Mirror) tools in MACHIN3tools, as demonstrated below.