Houdini 20.0 Nodes Geometry nodes

Trail geometry node

Creates trails behind points.

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The Trail op takes an input op and makes a trail of each point of the input op over the past several frames, and connects the trails in different ways. It will generate trails of any input geometry, whether it is a cube translating, a deforming surface, or particles. This is useful for multi-frame ghosting effects and temporal modeling.


Velocity Computation

The particles thrown off the end-most points receive a higher velocity than those close to the root of the L-system (enable Points display in Viewport Display):

Temporal Modeling

Temporal modeling with the Trail op: the corners of a translated and rotated cube are used as a source for the Trail op with a Trail Length of 50 frames connected by Columns.


Result Type

How to construct the trail geometry.

Trail Length

Number of frames in trail.

Trail Increment

Number of frames to skip in trail.

Cache Size

Number of frames to cache in RAM.

Reset Cache

Resets the cache memory buffer.

Evaluate Within Frame Range

Clamp evaluation between $FSTART and $FEND, otherwise may evaluate before start frame.


How to create the output mesh.

Close Rows

Closes the rows in the output mesh.

Velocity Scale

When computing velocity the resulting velocity will be scaled by this constant. Note there is an internal scale of $FPS to convert the measured change over a frame into a change over a second.

Velocity Approximation

This is the method that is used to approximate the velocity from the point positions.

You can choose between Backward Difference, Central Difference and Forward Difference. Generally, Central Difference gives more accurate results.

Compute Acceleration

When computing velocity, you can optionally also approximate acceleration by enabling this option.


The calculated accelerations will only be non-zero if Velocity Approximation is set to Central Difference.

Acceleration Attribute

The computed acceleration will be stored in this attribute.

Compute Angular Velocity

The difference in orientation of successive frames will be used to compute an angular velocity, w, for the points.


The N attribute is needed to compute angular velocity. Without N, the angular velocities are all zero.

Match by Attribute

Points on successive frames will be identified by using the provided integer attribute rather than the point number.

Attribute to Match

The name of the integer or string point attribute to use for matching successive frames.

See also

Geometry nodes