Bring Your Imagination to Life

Use Autodesk's video-editing software 'Combustion' to edit and hide wires in stunts such that the videos look real

Thursday, August 09, 2007

Most of us always wonder how those awe inspiring computer-generated images are created for movies. Scenes of action stunts, crashes, accidents, etc are created so professionally that it's impossible to distinguish between a real stunt and a computer-generated image. Combustion is a video-editing software used worldwide to ease the process of creating and editing videos including removal of unwanted wires and cracks from stunt scenes. Let's now use Combustion to remove a wire from an accident scene to make the scene look real.

We used two separate videos: one of a car coming down the street and another of a man walking on the street with a rope to perform the stunt of an accident.

Combustion's main menu is simple and well laid. The workspace window and toolbar is on left. Settings of various operators are on right, with the playback controls in centre	From the file menu choose File>New and make the following settings-Type: composite, Name: any (as 'wireremoval' here), Format: NTSC_DV, Duration: 30 frames with 2D mode

Press F3 to get the workspace panel, right click on the name of the composite and click on Import Footage. Make sure that one of the videos has transparent background	All the imported videos/GIF images would appear in layers in the workspace. Here you can see the wire used for the stunt performance. Click on play to see the unedited video clip

Go to the first frame, right click on the video with the wire, go to operators and select Paint. Press F3 to go to the workspace panel, you would notice that the Paint operator is visible just next to the Workspace menu	Press F2 to get the toolbar in front, use the Zoom tool to zoom on the wire in the video. Make sure to select a brush just wider than the wire and select a contrasting color such as red . Use the line tool to draw a line over the wire to hide it completely

Select line tool from the toolbar, press Tab to access the Edit Controls mode. Press 'A' to enable animate and re-position the line object using control points to hide the line in each frame. Once done press the key again to finish animating	Select line object and go to Paint's control panel and click Reveal in modes control. From source list click on Pick Operator and in Select Source box click Open footage. Browse the folder where the image of the background is stored and click OK

As soon as the image is imported, you would notice that the wire and the color on the line tool both become transparent as the background image acts as a mask to cover the line tool's position in each frame	Press F3 to open the Workspace panel, click on the composite name and play the animation to view the final result. On first playback it would take some time to render, but you would notice that the wire is now completly hidden from view

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