Blend Nodes
Three compositing nodes. Blend is the general one; Height Blend and Normal Blend exist because a plain crossfade is the wrong answer for height fields and for normal maps respectively. All three carry an optional Mask, and Height Blend carries two outputs.
Type id: blend
Composites two inputs through a blend mode, an opacity and an optional mask. The main compositing node, and the one you chain to stack material layers.
Inputs
- Base (any texture, optional): the background layer. Unconnected it resolves to fully transparent, which turns Blend into a cut-out rather than a layer stack.
- Blend (any texture, required): the foreground layer.
- Mask (grayscale, optional): where dark, the Base shows through (or transparency, if Base is unconnected).
Outputs
- Output (any texture): the composited result. The output’s advertised subtype follows the inputs: two height maps in gives a grayscale out, anything color gives a color out.
| Parameter | Type | Default | Range / Options | Notes |
|---|---|---|---|---|
| Mode | Choice | Normal | Normal, Multiply, Screen, Overlay, Add, Subtract, Lighten (Max), Darken (Min), Difference | Nine modes, in this order. Add clamps at white and Subtract at black. Lighten (Max) is the height-field workhorse: it unions two shapes without Add’s blow-out, since overlaps keep the taller value. Darken (Min) is the intersection. Difference extracts discrepancies between two maps. |
| Opacity | Float | 1.0 | 0.0 to 1.0 | How strongly the blend layer is applied. At 0 the output matches the Base. |
| Alpha Mode | Choice | Composite | Base Alpha, Composite, Blend Luminance | Base Alpha blends color only and inherits the Base’s alpha. With nothing connected to Base the whole result is transparent, which is why it is not the default. Composite is proper source-over: the two alphas combine. Blend Luminance uses the blend layer’s brightness as its alpha, so a grayscale layer becomes its own cutout. |
Height Blend
Section titled “Height Blend”Type id: height_blend
Merges two height maps by their heights instead of by opacity, so the taller surface punches through with a natural interlocking edge. This is how gravel sits in mud rather than fading into it. Purely per-pixel, so it stays seamless wherever its inputs do.
Inputs
- A (base) (grayscale, required): the lower surface.
- B (raised) (grayscale, required): the surface that emerges.
- Mask (grayscale, optional): where dark, A passes through unchanged. It applies to the Height output only; Blend Mask is never masked.
Outputs
- Height (grayscale): the merged height field.
- Blend Mask (grayscale): B’s share of the blend, which is the height-sorted boundary itself. Black where A wins outright, white where B does, ramping across the transition band. Feed it to ordinary Blend nodes so the matching albedo, roughness and normal layers composite along exactly the same interlocking seam. Re-deriving that boundary with a Threshold would not line up.
| Parameter | Type | Default | Range / Options | Notes |
|---|---|---|---|---|
| Balance | Float | 0.5 | 0.0 to 1.0 | Bias toward B. At 0 you see only A, at 1 only B; at 0.5 the two heights decide the boundary between them. |
| Transition | Float | 0.3 | 0.0 to 1.0 | Width of the blending band. At 0 the seam is a crisp height-sorted boundary; at 1 it softens into a crossfade. |
Both inputs are read as brightness.
Normal Blend
Section titled “Normal Blend”Type id: normal_blend
Combines two tangent-space normal maps as directions rather than as pixel values, so both sets of detail survive instead of one flattening the other. Use it any time you layer fine detail over a shaped base. A plain Blend averages the encodings, not the directions, and the result lights flat.
Inputs
- Base (color, required): the underlying normal map.
- Detail (color, required): the normal map layered on top.
- Mask (grayscale, optional): where dark, the Base passes through unchanged.
Outputs
- Output (color): a re-normalized tangent-space normal map. The Base’s alpha is carried through.
| Parameter | Type | Default | Range / Options | Notes |
|---|---|---|---|---|
| Mode | Choice | Whiteout | Linear, Whiteout, Reoriented, Detail | Linear is the cheapest and loses detail on steep bases. Whiteout is the usual default and holds detail on slopes far better. Reoriented rotates the detail into the base’s frame, so detail follows the shaped surface instead of the flat plane it was authored against; the correct choice for detail layered onto a strongly shaped base. Detail is Whiteout with the detail’s slope scaled by Intensity before the two are combined. |
| Intensity | Float | 1.0 | 0.0 to 4.0 | Weight of the Detail input. At 0 only the Base survives. In Linear, Whiteout and Reoriented it mixes between the Base and the combined result; in Detail it scales the detail’s slope instead, so it controls how far the detail tilts the base rather than how much of it replaces the base. |
This node is orientation-agnostic: both inputs must already agree on their green-channel convention. Convert an imported map with Normal Adjust before blending. A flat mid-gray texel is treated as pointing straight out rather than producing an invalid direction.