SDF
Offset, invert, round, and shell a distance field, in that order.
What it does
SDF converts a shape, image, or other compatible source into a Distance Field and applies a chain of distance-field operations on top: offset (expand or shrink), invert (flip inside and outside), round (soften corners), and shell (hollow out into a ring or outline).
The ops work directly on distance values, so they compose cleanly and stay resolution independent: rounding and shelling do not blur or pixelate. Viewport visualisation is set here too. Max Distance sets how far the field's influence reaches, Weight scales overall strength, Alpha controls the overlay's opacity, and Falloff shapes the gradient between inside and fully faded out, from a preset curve or a wired Curve node.
When to use it
Growing or shrinking a shape by a fixed distance: Offset.
Soft, rounded corners on an otherwise hard-edged shape: Round.
An outline or ring instead of a filled shape: Shell.
Flipping which side counts as inside: Invert.
Shaping a Distance Field before Contour, Volume Render or Flood Fill.
| Parameter | Type | Default |
|---|---|---|
source | OneOf([FieldOf(Sdf)]) | — |
offset | Number | 0 |
invert | Boolean | false |
round | Number | 0 |
shell | Number | 0 |
max_distance | Number | 100 |
weight | Number | 1 |
alpha | Number | 0.500 |
falloff | OneOf([Curve]) | Curve(Easing(BezierSpline { points: [... |
strength | Number | 1 |
Gotchas
Offset, Round and Shell all read as plain distances in scene units, so their effect scales with the size of the source shape. A Round of 10 is subtle on a huge shape and can swallow a tiny one entirely.
The Source input is required. With nothing wired, SDF has no field to transform and passes through empty. It does not error, and it produces nothing to view or chain further.
Max Distance, Weight, Alpha and Falloff affect only how the field is visualised and normalised for display. The underlying distance values that downstream nodes read are unchanged.
Worked example
Wire a shape (or any Distance-Field-compatible source) into Source.
Raise Round to soften its corners.
Raise Shell to turn the filled shape into an outline ring.
Enable Invert to treat the outside of the shape as inside instead.
Adjust Max Distance and Falloff to tune how the field reads in the viewport.
See also
Contour · Flood Fill · Volume Render · Distance fields & volumes