Floaters

A floater is a piece of detail geometry on a high poly that is not connected to the surface beneath it. A screw head, vent or small panel simply hovers just above the main mesh. When you bake, the detail still ends up in the normal map, because the baker records whatever high-poly surface it finds above the low poly. The technique has been in use for a long time: a 2006 Polycount thread is already titled "Baking Normal maps in maya using floating geometry" (Polycount forum: Baking Normal maps in maya using floating…).

#How floaters are baked

In a typical bake, rays travel from the bake cage toward the low poly, and the baker records the high-poly surface each ray meets (see baking). A floating screw head sits in the path of those rays, so its normals are captured. It makes no difference to the baker whether the screw is welded on.

This saves a lot of modeling. Cutting a detailed vent into a curved, subdivided surface means rerouting support loops and reworking the topology. A floater is modeled once, on its own, then placed and duplicated. You can move it until the moment you bake.

#Example

#Limits

• Silhouette and grazing angles. A floater is texture detail only. Detail that affects the silhouette belongs in the low poly; detail that does not can go in the bake (Polycount forum: I need some advice). Seen edge-on, a floater disappears.
• Distortion from averaged normals. Floaters can bake with skewed, distorted edges because of the low poly's averaged normals: "if you use floaters they'll often get distortion because of averaged normals" (Polycount forum: No More Distortions With Floaters - Flattened…).
• Ambient occlusion and depth. A floater has real height, which shows up in the AO and other maps. Flattening floaters to remove distortion changes this: one artist reported "much different AO bakes" than floaters with real depth (Polycount forum: No More Distortions With Floaters - Flattened…).
• Jagged edges in some bakers. One artist found floaters baked with jagged edges in Marmoset Toolbag 3 but smooth in Handplane. Adding a lip around the floater and making it thicker helped (Polycount forum: Is there a specific way i should be baking…).
• Distance. Floaters placed far above the surface cause trouble; bring them close "so they're not quite touching the pieces below them" (Polycount forum: Baking Normal maps in maya using floating…).

#Related terms

baking · bake cage · the high-to-low workflow · normal map · fixing baking artefacts · mesh decals (the mid-poly equivalent: floating geometry in the game mesh, as used for Star Citizen's "floating decals for livery and numbering" (Polycount forum: Star Citizen...The Gladiator...ART DUMP)).

#Further reading