positionPrevious
Provides the vertex position from the *previous frame* in local space, essential for implementing time-based effects like motion blur.
Core Advantages
Its core advantage is providing the necessary historical data (previous frame's position) to calculate vertex 'velocity', which is the cornerstone of advanced effects like motion blur and TAA, while completely abstracting the complex underlying data caching.
Common Uses
Generating a velocity buffer, which serves as the core data source for post-processing effects like Motion Blur and Temporal Anti-Aliasing (TAA).
How to adjust
This node provides read-only historical data. Adjustments are made by how you use it: for example, by calculating and visualizing the velocity vector, or by tuning the intensity parameters of post-processing effects that consume this velocity data (like motion blur).
Code Examples
1// Calculate the per-frame velocity vector of a vertex in local space
2const localVelocity = positionLocal.sub( positionPrevious );