Testing the Waters, ep. 2 - motion vector pass

(experiments in fluid dynamics)

composite

Because of the render-time motion blur, the previous "episode" took too long to complete. This time around, I tried a motion vector pass, which shaved about 85% off of rendering time.

initial simulation (filling the pools)

After modeling some pools, the next step was to fill them with a torrent of particles. Once the pools were full, I turned the water pressure down to a trickle. Total simulation time (filling + adjustments) amounted to maybe 2000 frames, or around a minute of animation. Only 120 (4 seconds) of those frames were used for the final video.

motion vector

I only concerned myself with two passes this time around: motion vector and specular. The motion vector pass is represented above.  Each additive color - red, green, and blue - corresponds to a different spacial dimension - respectively, the X, Y, & Z vectors. The compositing software uses those first two colors - red and green - to blur pixels along the width and height of an image.

specular pass with highlight filter

The specular pass is used to create a sparkly effect on the water.

steps

This video shows some of the steps of the process.