Slow motion filming & 3D animation

I just couldn’t let this slow motion footage go to waste that I shot on my iPhone from a ferry on the way to France. So when I got back home I was keen to find a 3D model of an RAF Sea King rescue helicopter and animate it flying over the slow motion footage of the sea.

The 3D model that I found was in the RAF yellow colour, so naturally we had to do some work to give it the old MVUK branding and colour scheme and make it our own. I did this by taking the image map for the original 3D model, and then edited and replaced parts of the map with my own graphics, branding and colours in Photoshop.

Calculating the speed

The tricky part was trying to calculate how fast the rotors would be travelling and the speed of the chopper in relation to the slow motion waves of the sea to make it look as natural as possible.

With the average helicopter propeller rotating at between 460 and 600 RPM (rotations per minute), and our footage at 100 FPS (frames per second) I worked that the propeller need to rotate 15 times (or 5,400 degrees) per second by doing something like this:

600 RPM = 60 rotations per second. 60 divided by 4 = 15 (because 100 frames of slow motion footage is actually 4 seconds of normal speed footage @25FPS)

I think I did a pretty good job of it nevertheless, and it was just a bit of fun just because I hate wasting decent footage that the world should see, especially when it’s in slow motion!

Because we love to keep things on-brand and up to date I changed the colour of the helicopter, added our new logo and put an extra little twist into the animation too – and updated the number of rotations of the propellers too, because I don’t think that I’d calculated it right the first time, just incase you were counting. But that’s just between me and you so don’t tell anyone!)

 
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