WATER SCENES VIRTUAL PRODUCTION
SMOOTH SAILING Filming water in VP requires various considerations, from keeping the set safe to blending real and virtual elements
For example, says Hall, when working with rain or particle effects, you want to ensure that the physical properties of the virtual rain – including spawn frequency, droplet size, wind direction and material – match those of the physical rain. “If there’s rain falling on a subject, it should also be in the virtual environment. Though it’s not always necessary; if you have a shallow depth-of-field in a large volume with physical rain, it may not be needed. This can save on GPU resources. “The VP supervisor will also be able to advise you on the capability of practical AS HARDWARE IMPROVES, WE CAN DO MORE IN REAL TIME, FOR more accurate and realistic VIRTUAL WATER”
water effects on the volume: LED panels have varying tolerances to humidity.” However, as we all know, water and electronics do not mix well. The environment has to be very controlled. “If shooting using a water tank and the LED volume as a backdrop, whether that is for underwater or above, the main thing to worry about is safety,” says Stiff. “These are large electronic devices next to a pool of water with actors. Keeping a decent distance between the water tank and the volume is wise, but this creates a gap between the practical and digital water. To allow the blend between real and digital, camera angles should be kept low to the water surface or high to obscure the edge of the water tank.” Tim Doubleday, head of on-set VP, Dimension and DNEG 360, claims that the main challenge is limiting practical water to a single area. “When done right, the two elements work brilliantly together since you get all the natural reflections and refractions from the LED wall in the practical water.” CATCH THE NEXT WAVE Water simulations have advanced to the point where they can now run in real time, including waves, crashing surf and complex water movements.
“The Fluid Flux plug-in for Unreal Engine seems to be widely used in the community and has produced great results,” says Hall. “I also know there has been impressive use of ICVFX for underwater scenes, so I’m interested to see how that progresses. ”As hardware improves, we can do more in real time, which will only lead to more accurate and realistic virtual water elements,” he adds. The way light interacts with water can also be rendered with a high degree of realism. Doubleday thinks we will see further advancements in how objects interact with water, such as a boat carving through water leaving a trail in its wake, or how a heavy object disperses water when dropped from a height. “These situations can be simulated using complex offline processes, but I can’t wait to see them running in real time on a giant LED wall!”
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