RealFlow 2015 Alpha Demo- VDB Meshing- Pyramid Water Gush

With RealFlow 2015's release on the Horizon and more and more exciting features been added to it, I wanted to make a new demo video of RealFlow 2015's VDB Meshing.

*NOTE Any screenshots of RealFlow 2015s UI are from the current Alpha Build and subject to change. Also I wont be showing too much here, so stay tuned for Next Limit at FMX 2015 For more info on new features in RealFlow 2015 !

The Demo Shot- 

I decided a Pyramid Gushing water looked quite cool! So I used this as a small scale production style test shot, of a large scale fluid sim to test the VDB Meshing. I thought it'd be nicer rather than just showing clay rendered mesh! On the other had, in production a lot of the fluid mesh here would be culled out due to the velocity of the fluid it would be a lot more spray rather than mesh, however I ignored this fact due to showing the mesh is the purpose of this shot.

Note this was sim'd on my second machine (specs below), over easter due to taking a few days off (Not had a proper day off for a long time!Ha!) and due to my main machine working on more awesome shots for The Sea Serpent's Song, Stay tuned for those, I also plan to make a breakdown reel when I am done on that project!

The Sim itself is pretty simple, Using RealFlows Hybrido Solver (FLIP) using two emitters inside the pipes, that have animated speed to have an initial burst of fluid which then turns into a stream of fluid. The particles Die on collision with the ground. I used Noise Fields and Vorticity Boost in the domain itself to get more Air/Turbulence in the fluid rather than a perfect stream of fluid. No Viscosity was used.

Core Fluid (Hybrido FLIP) Sim- Peak 7M Particles

I decided to do secondary sims, RealFlow 2015 includes a Bubbles only emitter so rather than doing Bubbles and Foam in one emitter for this test I did them as Separate Emitters. The Bubbles sim was HY-SPH and the Foam was dumb particles. The bubbles sim will come into play at render time a lot.

Rather than doing Colour By Velocity/Vorticity becuase I am meshing in RealFlow to Alembic and have not found a method to render a grey scale velocity map for comping (Like the method with Krakatoa and Frost, with VRays ExtraTex Vertex Colour render pass). I rendered the Bubbles with fluid mesh, and thus the bubbles are refracted through the fluid to get the White/Translucent Water Colour By Velocity look. This is actually what Colour By Velocity Mimics in the real world anyway, Bubbles refracting through fluid when fluid is move at high vort/velocity!

Bubbles to Refract Through Fluid Mesh

I used Dumb Particles for the foam sim just so I could have more of them and because the foam doesnt need to be as stringy as it would if its surface foam, its gonna break apart into droplets pretty quickly in this sim so thats why I went for Dumb Foam over doing an SPH or FLIP sim.

All sims and Info, VDB Meshing At the Bottom

The Meshing is very simple, Rather than using standard Hybrido meshing I added the new VDB Meshing node into my scene. VDB Meshing breif history- developed by Dreamworks in 2010/2011 VDB (OpenVDB) is way of using/storying Sparse Volumetric Data. Meshing is just one of its uses. Sony Picture Imageworks developed there own similar type called Field3D (.F3D) however VDB has taking over, theres lots of FX support for VDB all around now!

The RealFlow VDB Mehser does not only include the speed and versatility of VDB Meshing but also includes filters such as Erode, and Boolean operations. More info on LuisMs Blog Check it out It also features the "Splash Thinning Filter" as in the standard Hybrido Mesher, which is great for refining the mesh. So the final meshing was done in a few hours, I left it overnight and woke up to check on it, and it was done already :) Really Loving the VDB Meshing, the amount of detail and speed it can mesh from particles for high res sims is amazing, I cant wait to use it in production.

VDB Mehser "View As Points" Feature

Meshing Detail, Meshed this frame within a minute

Both the Mesh and the Secondary Sim particles were cached out as Alembic sequences and stitched together so they could be rendered through V-Ray Alembic Proxies. The Advantage of caching them out in a seq as frames rather than as one file means if something goes wrong like a system crash, you wont loose the whole cache, only the frame the sim/system crashed on. If you were to cache/wrire to one alembic file and had a system crash or powercut then you've just wasted hours of sim time, down the drain... Literately :)

 RealFlow Stitcher Tool  For Alembic Sequences

VDB Mesh Vray Proxy back in Max. (Viewport Preview)

The Pyramid/pipes was a very simple model a 5 minute job, all the detail/stone comes from V-Ray Displacement Modifier using a Standard Max Tiles Procedural Map,  UV Map'd onto the Pyramid, The additional stone detail comes from Fractal Noise Bump maps ontop of the Displacement.   The Lighting was done with Two V-Ray lights and a HDRI Map, as you can see in the final. The water shader I wanted was muddy water pretty simple setup using a standard VRayMtl with Fog to colour the refractions/water.

Muddy Water Shader WIP

The trees were added in to add more completion to the shot, aswell as hide the mesh kill on collison with the ground, they are basic trees (From Maya Paint Effects Actually) using PFlow to scatter them, and then baked into an Alembic file using Exocortex Crate and rendered through VRay Alembic Proxy also. 

Compositing was very simple in AE as all passes apart from the foam were beauty passes, I also rendered the mesh on its own as a claymesh pass.

Final Comp Of The Test Shot^

Big Thanks to Next Limit, Especially Gus,Luis and Dan aswell as the awesome RealFlow Developers lead by Angel Tena! 

Final Demo Video - RealFlow 2015 VDB Meshing- Pryamid Water Gush

Thanks For Looking, Be Sure to check back for more of my work, and Checkout RealFlow 2015 at FMX :) - Niall