Impact Based Fluid Effects in Houdini

Taught by Alvin Yap

Course Number:
Software Version:
Original Run Date:
October 2020 
6 hours 50 minutes 
This course, taught by Alvin Yap, is an in-depth look at creating an open ocean simulation in Houdini, rendered with Redshift and basic compositing in Nuke.

The course begins with a close look at the simulation geometry provided, followed by making the necessary optimizations and modifications to get them prepared for the ocean simulation. We'll dive into aspects such as creating proper subframe data, as well as creating watertight geometry for complex objects.

Next, we will look into generating the main simulation using the Flip Flat Tank, and use simple yet effective techniques to create a realistic water effect. We then move on to creating and matching an open ocean using the Ocean Spectrum tools and touch on Redshift briefly to generate our open ocean render with displacements.

The next topic on the list is generating the white water elements for the flip simulation where we\'ll look at the white water solver, and taking a surprising turn by using the white water solver only for the foam layer and creating a custom POPs sim for the spray and bubble elements. With the whitewater elements complete, we then look to generating volumes from the spray and foam elements.

We then get into rendering with Redshift, where we learn how to create materials and tweak them for our final look, then we\'ll jump in between Nuke and Houdini and we figure out how to create various AOVs, mattes, as well as our own custom AOV in order to adjust specific areas of the comp. In closing, we'l look into separating some elements in the render so as to get a defocus effect in Nuke without artifacts as well as a quick overview on some quality settings in Redshift.

Alvin Yap started his career as a 3D Generalist before taking an internship role with Side Effects and has been using Houdini since 2008. He has worked with several companies such as Rising Sun Pictures, Framestore, and Sony Pictures Imageworks.
Impact Based Fluid Effects in Houdini
Watch our overview of the course

Class Listing

Class 1: Geometry Prep Part 1

This class takes a look at the assets we have to work with, and we will check our assets to ensure that they are watertight and suitable for simulation. We also take a look at generating subframe data.

Class 2: Geometry Prep Part 2

We continue from Class 01 where we apply the techniques onto the geometry, and learn how to generate watertight geometry for open surfaces.

Class 3: Flip Sim Part 1

This class looks into creating a basic ocean setup, and brings up the topic of optimizing animations and cameras for a simulation. We finish this video by setting up the fluid sim so that we can adjust quickly create smaller simulation regions for faster iteration times.

Class 4: Flip Sim Part 2

We continue from Class 03 and create our fluid basic fluid simlation and ensure that our colliders work properly.

Class 5: Flip Sim Part 3

We look at references and adjust the solver and add forces to create a fluid simlation. We also look into ways to tame the simulation so that it stays within the boundaries we set.

Class 6: Flip Sim Part 4

This final video on the fluid simulation completes the discussion on keeping the motion of the fluid within the bounds we have set, as well as means to make the simulation settle quickly without looking viscous.

Class 7: Meshing

This video focuses on generating a mesh from the fluid sim. Topics include using the various smoothing and masking functions, as well as generating geometry that stretches out the ocean into the distance.

Class 8: Ocean Spectrum Part 1

This video shows us how we can generate and match reference of an open ocean using the ocean spectrum nodes. We dip a toe into Redshift and render an ocean using displacements.

Class 9: Ocean Spectrum Part 2

We then continue to apply this open ocean to our mesh generated in Class 07. We also encounter some boundary issues, and fix them.

Class 10: White Water Part 1

This class goes over the white water tools, primariliy figuring out how to generate the emission volume, and start on a basic whitewater simulation.

Class 11: White Water Part 2

We look closely at the tools used to to create various looks on the foam, ensure that the foam aligns closely with the render mesh, and finally create our own custom setup to generate the spray and bubbles using pops.

Class 12: White Water Part 3

We complete the custom spray/bubble setup, and then look how we can ensure our foam sticks closely to the surface in a realistic manner.

Class 13: White Water Part 4

We look at some quick render optimizations, followed by rasterizing the spray and fluid volumes and setting attributes for the bubbles.

Class 14: Rendering Part 1

This class looks into creating the materials for the ocean surface. Partway through we realize the displacements are off and we fix it. We then look into creating a mask to reduce displacements in areas that are moving fast.

Class 15: Rendering Part 2

This class focuses on tuning the volume material for the combined spray and foam volume as well as the bubbles.

Class 16: AOVs and Compositing Part 1

This class focuses on generating the various render passes and combining them together in Nuke. We then take a closer look into generating mattes to allow specific regions to be adjusted in Nuke.

Class 17: AOVs and Compositing Part 2

We continue from the previous class and look into how to split up a render in order to create a defocus effect in Nuke. We conclude the course with a quick discussion on how to setup Redshift for high quality output for the final Nuke comp.