Documentation / Node reference / geo nodes

geo/Measure

Measures the input and writes the number onto it as an attribute.

Attributes

Computes one quantity per entity and stores it, so the rest of the graph can read it: a geo/Delete or a group rule can select on it, an expression can reference it, and the spreadsheet shows it.

Which entity carries the result follows what the measurement is OF. Area and perimeter belong to a face, so they land on the PRIMITIVES. Curvature belongs to a point, so it lands on the POINTS. Area, volume and genus of a whole solid belong to the body, so they land on the OBJECT.

A MANIFOLD_3D solid, the geometry a geo/M3DCreate produces, is measured by the Manifold library itself and in world space: area is its whole surface, volume is what it encloses, and genus counts the tunnels through it (0 for a ball, 1 for a torus). Those three are the only measurements a solid can answer, since it carries no points or primitives of its own. Build a solid first if what you have is a mesh.

Volume on a VOXEL input is the occupied volume of the grid instead.

Parameters

Name Type What it does
type UInt8 AREA · PERIMETER · VOLUME · CURVATURE · GENUS What to measure. Area and perimeter are per face and need a mesh. Curvature is per point and needs a triangle or quad mesh. Volume needs a solid (geo/M3DCreate) or a voxel grid. Genus counts the tunnels through a solid and needs a geo/M3DCreate.
curvatureType UInt8 MEAN · GAUSSIAN · MIN · MAX Which curvature to write: mean, gaussian, or one of the two principal curvatures.
attributeName AttributeName The name the result is written under. It is not tied to what is measured, so a graph measuring twice can keep both numbers by giving them different names.
addDirection Bool Also write a per-point .CURVATURE_DIRECTION vector, the unit direction of maximum principal curvature. Useful to drive a copy or a hair direction along the shape's flow.
smoothingRadius Float Averages the curvature over a neighbourhood of about this radius, in the units of the input. Details smaller than it, such as skin texture or scan noise, fade away, and larger forms keep their curvature and direction. 0 measures each point on its own. The average follows the surface, so it never reaches across a gap to another part of the shape.
allocator UInt8 TEMP · POOL · FLAT_POOL Which allocator backs the scratch buffers: a pool clears at the end of the cook, temp at the end of the frame.

See also

This page is generated from the engine, so it describes the release you can download. The same text is in the editor's Help panel next to the node itself.