Niall Horn VFX's Blog- Making Of My Work & RnD

Friday, 21 March 2014

Battleship Explosion Project

If you look back a few months ago I did a Battleship Explosion shot, I was not happy with it, a lot of things were not right and I wanted to wait a little while before I came back and re did again.

The Making:

This time round I started doing about a weeks worth of RnD (aswell as all the previous weeks/months) for the Ship Destruction, Theres many different approaches I tried everything from Thinking Particles to Cloth Simulation. For this Project I actually used no simulation for the destruction at all, I had my ship asset which I split into two pieces where the explosion occurs, then I just animated them to jump out the water and then fall back down. Then I used Rayfire to detach some of the elements of the ship and used a basic PFlow system to throw some debri into the air.Next my plan was to bake these particles out to geometry which I did using PFlow Baker from Script Spot. I would then use these pieces as an Object Src in Fume FX.

                                             The Destruction Setup in the Max Viewport

Fume FX:

Once I had finished the layout, added the camera move and locked the shot and the scene file I jumped into a new scene to setup the FumeFX sims. 

The Fume FX scene used 2 grids, one for the fireball explosions and the other one for the fiery smoke trails/tendrils. For both grids I used Colour Caching, this enabled me to use multiple smoke colours in the same gird, for the Fireball grid, There were 3 Fireball PFlow systems each emitting very quickly a burst of particles and then deleting, Two of the smokes were black smoke and the other was a lighter grey to give some variation to the colour. The other Grid is the using One PFlow system for the trails which is emitting around 70 Particles that get pulled down by gravity after a few frames, then using the Spawn operator with a low lifetime of the spawned particles you can create nice fiery smoke trails.

                                              A very simple low res test of fiery smoke trails

The Fume fx sim was meant to have a quick burst of fire, and then burn out into rolling smoke. The Fume FX sims for the final grids took around 8 hours to sim and to render around 10 hours. A lot of the Fume FX look is added in comp with colour correction and glows, I even added a sharpen filter that was animated to show on the smoke making the smoke look a lot more bolder and higher quality.

A Viewport Preview of the Fume FX Simulations

Fume FX Comp Render

Next I knew that due to avoiding using 3D Fluid simulations for the Ship and Debri interaction with the ocean I was going to have to fake some water splashes, I setup a new scene from the Layout scene so I could create 3 water splashes using PFlow and Krakatoa. First was a big impact water splash for when the ship explodes (I did not use this in the final comp, due to it hiding the Explosion Render to much). Another was a splash for when the back of the ship hits the water as it lifts in the air, and the other was a water shock wave a long the Ocean surface. The Ocean surface was made with Houdini Ocean Toolkit and for this scene I used a low res version so the Particle sim time would be quicker. All the systems were realtivly simple and using pretty much the same setup as one another, I am really excited to work on this shot again but doing full 3D Fluid sims in Reallfow as I know it will make it so much better.

                                                                  The PFlow Setups
Destruction, Explosion, Water Splash passes Preivews

I also Did A quick test a few weeks ago on making a water splash in 3DS Max with PFlow and Krakatoa. Looking back I need to add a Water Shock wave around the base of the explosion.

Once this pass was rendered in Krakatoa I moved onto lighting/shading/rendering the ship and the Ocean. I switched to V-Ray for this as well as using V-Ray for the Fume FX Global Illumination pass. I setup shaders for the ships hull, the guns on the ship aswell as misc parts of the ship. Each Shader was using different relction values the ships hull is meant to be a bit more "rusty" then say the ships guns.

The Ocean Shader was one of which I have been developing for my Realflow Work, It has fake Foam Interaction using the V-Ray dirt shader due to the fact of there been no ship/water interaction. The lighting for the shot was based on a HDRI (High Dynamic Range Image) of a sky as well as a few V-Ray Lights. One V-Ray Light I used to fake the Reflection of the fire on the Ocean which was key framed to fade off when the explosion fire burns out. This really helped me in comp as the FumeFX Pass is not actully been reflected on the water surface. For Reflection passes I usually just hand key them onto say an ocean surface in comp and add some 2D noise so it kind of matches the ocean wave displacment, a cheap trick that works well!

The Ocean and Ship Pass Rendering

The Plan was then to have a skydome pass which I did render but in the end I used a "Checker Dome" for the background this is due to you been able to see the Fume FX sim better which enables me to get better feedback on what to improve for the future. However Here is a test comp using the skydome pass (This was before all render passes were complete).

It Looks pretty ugly! 

Next was the Final Two Stages all done in one long night! While Listening to some FXGuide Podcasts! Compositing was done in After Effects, The Main things were blending all the elements together and making the Fume Fx sim look much more realistic, adding a lot of Colour Correction to it aswell as glows to really make it look the part. For this shot I faked all my motion blur using Real Smart Motion Blur which is really good when used properly! It saves rendering Motion blur or even velocity passes out of 3DS Max. Its a really exciting stage seeing all your hard work come together. I made a few shot changing decisions in comp, like getting rid of some of the water spary passes as well as getting rid of the sky dome. I was going to leave BG Black but rendered a Checker Dome pass out. I also created a new style of  Breakdown that you see a lot on ILM's Breakdowns and some other big name studios, its where you see the camera fly around all the layers in the comp. For this I duplicated my Shot Comp and made a 3D Camera and all the passes 3D Layers, I added White Borders to the edges so you can see each layer clearly. Then All I did was move each later the same distance behind on another and rescaled them so they lined back up to the final comp. The Using the Camera tool with a 3D Camera I create a camera animation that tracks around to see all the Layers and then tracks back to the camera view. 

This is the Type of 3D Layer Breakdown I created!

Once the shot was Final at around 2 AM in the morning I set it to render for After Effects and uploaded it!

I have got some really positive feedback, and some critique about it been to fast making the scale look small, I am currently in the process of correcting his and will be re uploading the Version 2 soon! Overall I spent around 5 days of 6-8 Hours per day working on this (including 2 days rendering) So 3 Days really! 


I hope this article was informative, I have a lot of ideas for VFX shots coming soon. 

Thanks For Looking!

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