Houdini 20.5 Nodes Geometry nodes

Flatten geometry node

Flattens 3D geometry onto a plane.

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Since 20.0

Overview

Use this SOP to flatten 3D geometry by moving selected points to a 2D plane.

The Clip node deletes points on a plane to clip 3D geometry on one side of that plane. If you want to delete instead of flatten points, use the Clip node.

This node was created to flatten the bottom of cloud geometry.

Tips and tricks

  • You can use Flatten to “flatten” geometry onto a unit sphere. Set Direction to Use Attribute, set Direction Attribute to P, set Flatten to To Single Plane, and Distance to 1.0.

Parameters

Group

The subset of the input geometry to flatten. If this is blank, the node affects all the input geometry.

Orientation

Orient Using

Whether to orient the flattening plane using a vector (the direction perpendicular to the flattening plane) or rotation.

Origin

The origin of the flattening plane. Set Uniform moves all points to the plane position specified in the parameters. You can set this to Use Attribute to move each point to a plane specified by an attribute on the point.

The default values are 0, 0, 0 and Set Uniform.

Origin Attribute

When Origin is Use Attribute, this is the point attribute to use as the origin value.

The default value is pivot.

Direction

When Orient Using is Direction, this is the direction perpendicular to the flattening plane. The origin point and this direction define the plane’s location and orientation. You can set this to Use Attribute to orient the plane using an attribute on each point.

The default values are 0, 1, 0 and Set Uniform.

Direction Attribute

When Direction is Use Attribute, this is the point attribute to use as the flattening direction.

The default value is N.

Rotation

When Orient Using is Rotation, this is the rotation vector of the flattening plane (from Y-up).

The default values are -90, 0, 0 and Set Uniform.

Rotation Attribute

When Rotation is Use Attribute, this is the point attribute to use as the rotation value.

The default value is rot.

Flatten

Flatten

Whether to use one or two planes to flatten the 3D geometry.

Between Planes (default)

Flattens 3D geometry on one side of the flattening plane. You can also define two offset planes with the Distance Min and Distance Max parameters, and flatten all points onto those planes.

To Single Plane

Flattens 3D geometry on both sides of the plane onto the plane. Use this setting to flatten 3D geometry to a 2D plane.

Strength

The amount of flattening. The default value of 1 flattens the geometry to the given plane. Lower values blend between the original and the flattened shape to smooth and flatten the shape.

Values higher than 1 move the points beyond the plane into an inverse shape.

Distance Min

When Flatten is set to Between Planes, this is the distance from the origin to the minimum plane. The points below this value will be flattened to this plane.

The default value is 0.

Distance Max

When Flatten is set to Between Planes, this is the distance from the origin to the maximum plane. The points above this value will be flattened to this plane.

The default value is 1.

Distance

When Flatten is set to To Single Plane, this moves the plane along its normal.

The default value is 0.

Thickness Attribute

If you turn this parameter on and set it to the name of an attribute, the node offsets the flattening plane for each node by the value of this attribute.

For example, using the default value of pscale on a scattered point cloud that has spheres instanced on it aligns the spheres to sit on a ground plane.

A point cloud without (left) and with (right) flattening to a ground plane. The instanced sphere primitives aren’t aligned on the ground plane because the thickness attribute isn’t used:

A point cloud flattened without (left) and with (right) using the thickness attribute. The instanced sphere primitives are aligned on the ground plane:

See also

Geometry nodes