Hi Guys,
How come Aliens never decide to crash land there UFO's up North in the UK?
In Films they always invade London or LA, or New York!! This is my first shot of integrating a RealFlow Shot into a Live Action Plate, In this article I will be going into a detailed making of process on how this shot was created.
Modelling/Texturing of the UFO Asset
I made the UFO Asset last year Modelling was done in 3DS Max, and Texturing in Mudbox and Photoshop. I wanted to make my own Asset instead of downloading one as a personal challenge to get to know the basics of modelling and texturing.
Getting the Live Action Plate, Matchmoving & Animation
The Live Action Plate was shot while I was gathering reference pictures for a college project, Outside of my college is the Docks and theres this huge "pool" of water that links to the docks and I always thought it would be cool to have a UFO Crash Land in there, I then came up with a whole bunch of other ideas for a UFO attack sequence but this shot stuck in my head for the past 6 Months. The Live Action Plate was shot from a shoulder rig on a Canon 550D, The Shot was then Tracked/Matchmoved in After Effects using the 3D Camera Tracker that's built in, all the renders were comp'd as 3D Layers, there was no rendering from the camera in 3DS Max, it was kind of faked in comp, More on this below.
The Animation of the UFO was done over 135 Frames to match the cameras pan down to the docks where the UFO would be crashing landing, but then it rises back to the surface to show that its ok and maybe the aliens are ready to invade?! I rendred a simple test to check the animation worked well with the plate:
RealFlow Fluid Simulations
All the Fluid Sims were done in RealFlow 2013 with Hybrido. I have been using RealFlow and Hybrido for a year and a half. Most of the Production time on the shot was spent in RealFlow getting the splash looking nice! For Non RealFlow Users, Hybrido is RealFlows Large Scale Fluid Solver using FLIP simulation.
The first step was getting the Core Fluid sim looking nice, I knew I would be blending the Sim with Real water from the Live Action Plate so I made this fluid volume as large as possible while keeping enough detail in the sim. I ran several low res tests of the Core Fluid sim, trying to keep the scale of the fluid looking realistic, I ended up increasing the Gravity a bit due to the splash of the UFO making the particles go quite far into the air. When I was happy with the core fluid tests I let it sim a High Res Iteration over 12 Hours.
Final Core Fluid Sim 01
Final Core Fluid Sim 02
Next was the Splash and Splash and Foam Secondary Simulations, I wanted a very dense Splash for this shot so I used two Splash Passes one Dumb/Ballistic Particles and the other was a SPH Liquid Sim. I did one Dumb Splash and Foam sim this generated the basic splash and the main body of Foam. I also did a SPH Liquid Splash Sim to get the big splash you see in the final shot, The Actual splash sim also generates some foam, but due to some particles still be generated I gradually got rid of the splash sim in comp after the initial big WhiteWater impact, I used a mask with lots of feather in comp to gradually "Fade it out" kind of. Then the Dumb Splash and Foam sim is the foam on the surface.
Dumb Splash and Foam Sim
Splash Sims on the Bottom
The Mesh was generated in RealFlow and took around 4-5 Hours to Mesh. All of these sims were then brought back into 3DS Max for Rendering.
Rendering
The RealFlow Mesh was loaded back into 3DS Max using the BIN Loader, and the Particles using Krakatoa's PRT loaders with PRT Caches for the Splash and Splash and Foam Sims. The main part of the rendering stage was getting the water shader to match the Live Action Plate's water. I used my Ocean Shader with no Displacement other than some noise on the surface. I decied there was no need for Velocity/Vorticty shading of the water due to the Large Splash cloud you do not see the fluid mesh to much apart from the surface interaction. As Said I used my Ocean Shader setup without displacement and just some Bump noise to get the CG water looking like the water in the plate.
Water Rendering Test 01
Water Rendering Test 02
In the end I took a lot of saturation out of the shader, the water starts to look almost grey but it works well in the plate. I also used a Still Frame of the Plate to make sure that the Camera in 3DS Max will line up with the plate when the renders are used as 3D Layers in Compositing. The Fluid was lit using a HDRI of a harbour of which the reflection look very similar to the plate, the HDR also was shot on a sunny day as was the plate.
The Splash and Splash And Foam Passes were rendered as Particles with Krakatoa I used Specularity on the Particles with a basic Material to get the particles looking more like white water and less "powdery".
Splash and Foam Rendering- Krakatoa
The UFO Was rendered on its own pass so that the fluid could be blended easily without affecting the UFO lighting/rendering. The Fluid Mesh pass also has the UFO in but using the V-Ray Mtl Wrapper it Masks the UFO like a MatteShadow Shader so that the UFO fits right into the fluid pass. The Splash and Foam passes also uses the UFO as a Matte Object so that they don't occlude where the UFO will be.
Compositing
Compositing for this shot took a lot of work, the big task of blending the CG Water with the Live Action Water. The First thing was colour correcting, the water shader was close to matching the real water however it still needed blending, I used Masks on each side of the mesh to blend it with a lot of feathering.
Its pretty hard to tell where the blend is when theres the motion blur on top also.
Trying to Achieve Seamless Blending- Early RnD Low Res Mesh
I comp'd all the Renders in there own comp first, before copying each pass to the live action comp, and then using them as 3D Layers.
Render Passes Comp
One cool thing I did is that because the UFO does not crash into the water until frame 33 I only rendered the Fluid Mesh from frame 30 onwards and I just used frame 30 as a still for the first 30 frames before switching to the render sequence of frame 31-135. This saved a good 3 hours render time.
As I said before, the camera tracking was done completely in After Effects, there was no exporting camera data to 3DS Max, What I did was used a camera in Max that lines up with the original live action plates perspective, I then made all the elements 3D Layers, made sure they all had the same transforms on. This then make them fit into the original camera move.
The Splash and Foam has some colour correction on also, also some more blur and motion blur using RSMB. Then the UFO had its own colour correction on also a bit of RSMB Motion Blur to save rendering out motion blur. Also I added some Water on the lens, just with a still image of water droplets on black, then animated a mask, to quickly reveal them as if the camera lens gets splashed. I think it adds quite a bit to it all!
I also added a mini Breakdown onto the shot, just showing where the CG Water is and then how it blends into the plate.
Evaluation Thoughts
I am really happy how this shot has come out, not only have I got a awesome Fluid Sim shot but I have actually blended it into a Live Action Plate.
I really like the Splash Particles and how nicely they came out, When I get into the Relase Version of RealFlow 2014, I will then be able to render mist, which will add even more realism to my Fluid Sim shots, this is where I want to give a big shout out and thanks to Next Limit for all there support with my RealFlow work, and for giving me (A 17 Year Old Student) a chance to Alpha/Beta Test RealFlow 2014. Can't wait to see what amazing VFX images artists are gonna create with it, I know now with the success of this shot I have more ambitious ideas!
This shot I worked on over a month, but the bulk of the work was done in 2 weeks, this makes me think that maybe a VFX sequence for my Showreel will actually be a good and realistic idea!
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