By Jeff Bertrand
For this project, we were to composite a series of live footage with cg elements. The story for my sequences is a car taking off, speeding down the highway and crashing in the end.
Live on CG
I used my BMW M3 model with the smoke from the green screen footage to simulate acceleration. First I made the scene in Blender. I surrounded the model with grass and sky textures so the reflections would show up on the car.
Then I made a matte of the smoke using a combination of blurring, color correction, translation, and scale.
Then I rendered and animated the car. Here is a still from the video.
CG on Live
For this video, I used the M3 model following a path that is similar to the stock footage of Mauna Kea. I built the scene around the vehicle so that reflections would show. The scenery is not rendered in the final image, but the car still picks up the reflections.
In order to simulate the shadow underneath the car, I built a semi-transparent road that matches the curvature of the highway. The road was rendered in the final image, but with opacity set to about 40%. I still had a 3D model of the road underneath so that there were dark reflections on the bottom of the car, but that model was not rendered in the final.
The animation did not look very natural without motion blur, so I added some in the final image.
Live on Live
The final video is the car exploding after speeding along the highway. The ridge of the road naturally blocked the bottom of the green screen footage so the explosion looks like it was part of the scene. The top of the explosion was cropped in the original footage so putting the explosion near the top mitigated the problem. Here is the matte of the explosion.
And here is the final image with the matte color corrected on top of the original video.
The original source footage was downloaded from 3 different sites. This video has each of them appended together.
1. Mauna Kea stock footage