Blender 5.0 Geometry Nodes > Signed Distance Field Nodes

Geometry Nodes is a Visual Programming feature of Blender similar to Grasshopper in Rhino. In simple terms, a Node Tree is constructed to generate 3D geometry that can be parametrically adjusted, a program where variables can be modified to generate a different oucome. Between the initial INPUT node(s) and the OUTPUT node, modifier nodes are added to transform and manipulate mesh geometry so that the end result is different from the original condition. A good overview of Blender Geometry Nodes can be read here

Signed Distance Field (SDF) Nodes in Blender

Normally, Blender respresents geometry as a polygonal mesh. The "skin" surfaces of 3D shape ("geometry") are defined by a gridded of polygonal cells. Using small shapes to describe a bigger shape. The cells of the grid are polygons and the more polygons that are used to describe a geometric shape, the smoother it will appear (the facets become less visible). The downside of more polygons is greater demand on your computer to calculate and display their shape, size and position continuously. Too many polygons and your PC may crash (when it's computational capabilities are exceeded).

SDF is an alternative method to describe geometry by utilizing mathematical equations and a field of numerical values. A Negative Value is inside a geometry. A Positive Value is outside a geometry. A value of Zero is exact on the surface or skin of the geometry, between the boundary between the inside and outside of the geometry. This method of shape representation is much less demanding for a PC to calculate than the mesh method. More about SDFs in Blender can be read here.

From Blender 5.0, new Volume Density and Signed Distance Field (SDF) nodes were added. SDFs allow geometries to be combined with one another with better topological transitions than with traditional mesh modeling techniques.

An SDF Geometry Node Tree

In the example below, a UNION boolean of 2 geometries is constructed, showing smooth topology transitions between the two.

1. A Cube geometry (represented by the Group Input node) and a Cylinder geometry (Cylinder node) are first added.
2. Transform Geometry nodes are added for each geometry to allow for Transform, Rotation and Scale manipulations to be done.
3. Mesh to SDF Grid nodes are added for each geometry...and the meshes are now converted from meshes to 2 sets of distance field data.
4. Next, the 2 SDF Grids are combined using a SDF Grid Boolean node, set to Union.
5. Then an SDF Laplacian node is added to allow for smoothing control via the Iteration parameter.
6. A Grid to Mesh node is added to convert the unioned SDF fields back into a mesh.
7. A Set Material node is added to allow for applying of material to the newly created geometry.
8. Lastly, a connection is made to the Group Output node to display the final result of all operations.