Houdini 21.0 Nodes Geometry nodes

Labs Random Selection 1.1 geometry node

Randomly selects a subset of input points or primitives.

The Random Selection provides multiple intuitive ways to isolate, color, or group a random subset of input points or primitives.

Parameters

Group

The names of the groups to select from. Leave this blank to affect all elements in the input.

Elements

What class of elements to operate on: points or primitives.

Selection Mode

Exact Number modes output precise numbers of selected elements.

Exact Number - Randomize Element Order scrambles the input element order before selection, and it is the only mode that does this.

Probability evaluates selection separately on a per-element basis, so the final selection ratio and number are not precise and are affected by Random Seed.

Periodic modes periodically select and then skip a certain number of elements following to the input element order. The numbers of selected and skipped elements in different periods can be constant or random.

Ratio

The ratio of the number of elements to select to the total number of elements.

Count

The number of elements to select.

Probability

An individual element’s probability of selection.

Random Seed

Affects the selection pattern. In Probability mode, it also affects the final selection ratio and number.

Periodic

Offset

Offsets the selection pattern.

Select

The number of elements to select in the first part of every period.

Skip

The number of elements to skip in the second part of every period.

Select Min

The minimum number of elements to select in the first part of every period. The final number is randomly generated between the min and max on a per-period basis.

Select Max

The maximum number of elements to select in the first part of every period. The final number is randomly generated between the min and max on a per-period basis.

Skip Min

The minimum number of elements to skip in the second part of every period. The final number is randomly generated between the min and max on a per-period basis.

Skip Max

The maximum number of elements to skip in the second part of every period. The final number is randomly generated between the min and max on a per-period basis.

Delete Non-selected

Deletes the elements that were not selected.

Delete Selected

Deletes all elements that were selected.

Create Group from Selected

Creates a group containing the randomly selected elements.

Group Name

Name of the group created from the selected elements.

Integer Attribute from Selected

Creates an integer attribute marking selected elements. Selected elements are assigned a value of 1, while non-selected elements receive 0.

Attribute Name

Name of the integer attribute created when Integer Attribute from Selected is enabled.

Color Selected

Color Selected

Applies a color to the selected elements for visualization in the viewport.

Delete All Existing Color Attributes

Removes Cd attributes of all types, point, primitive, vertex, or detail. This gives a clean slate so only the new color attributes will exist. Note some combinations, like primitive and point attributes, allow attributes of the same name.

Color Type

What sort of color to add. Can be one of:

Constant

The same color is applied to all of the group.

Bounding Box

A color gradient is applied depending on the position of the entity in the bounding box.

Random

A random color is assigned to each group element.

Ramp from Attribute

An incoming attribute is remapped to color according to the provided ramp.

Color

This is the color to apply when in Constant mode.

Color Seed

This is the random number seed for the Random mode.

Attribute

The attribute to be remapped into color. If it is a single float, it is indexed directly into the ramp. If it is more than one float, each component is remapped independently.

Range

The incoming range of valid attribute values. Attribute values within this range will be remapped to 0-1 for the ramp lookup, values outside will be clamped.

Geometry nodes