The Grow Bounds effect increases the layer size for the effect that directly follows it. This effect is most useful with layers that have Collapse Transformations/Continuously Rasterize enabled, because they render using a buffer that’s the size of the composition. For example, if you apply Drop Shadow to a text layer that’s partially out of the composition frame, the shadow will be clipped because only the portion of the text that’s in the composition frame will cast a shadow. Applying the Grow Bounds effect before the Drop Shadow effect prevents the shadow from being cut off. The number of pixels you specify increases the height and width of the layer’s buffer.

This effect works with 8-bpc, 16-bpc, and 32-bpc color.

Original (top left); the Wave Warp effect is constrained by dimensions of layer (bottom left); Grow Bounds effect fixes problem (bottom right).