New geo/SDF nodes

Polygonjs 2.0.58 is out, and it brings SDF modeling.

SDF stands for signed distance field. Instead of building a mesh from vertices, you describe a shape as a distance function, then combine those shapes with booleans and triangulate at the end. It works for hard surfaces as well as organic shapes, and especially well when you mix both.

One of the main benefits is that the models are guaranteed to be watertight, which makes them 3D-printer friendly.

Polygonjs has had SDF nodes for years, but they could only be used in a shader, for pure raymarching. Their output could not become a model. That is now possible.

The new nodes live in the GEO context. geo/SDFBox, geo/SDFSphere, geo/SDFTorus, geo/SDFCapsule and the rest of the primitives create fields. geo/SDFBoolean unions, subtracts and intersects them, with a fillet or a chamfer on the seam. A great advantage of those nodes being in the GEO context is that you can combine them with standard nodes like geo/CopyToPoints or geo/Transform.

geo/SDFRound, geo/SDFOnion, geo/SDFMirror, geo/SDFRepeat and geo/SDFElongate give you more ways to tweak a model.

Once you are happy with the result, use geo/SDFTriangulate to convert it to a mesh you can export or print.

Three examples to start from:

• SDF Boolean Basic shows how to combine a sphere and a box.
• SDF Boolean with different colors shows how to add colors.
• SDF for 3D printing is more involved, and shows how to end up with a model you can 3D print.

As with any other example, you can modify them as you like, copy them into your scene, and learn how to make more elaborate setups.

As always, tell me what you build, and what is missing. Reply to this email, or say hello in the Discord, Bluesky or Twitter.

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