Category: Class

Week 25 – Treating Fire Footage

Time Nodes:

• Retime: Allows you to slow down, speed up, or even reverse selected frames in a clip without necessarily altering its overall length.
• OFlow: Provides more detailed control than the Retime node, such as method, smoothness, shutter, etc.
• Kronos (NukeX only): Similar to the OFlow node, but works better for some footage.

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Treating Fire Footage:

• Simply extracting the alpha and merging it over the footage often looks fake. To achieve a more detailed alpha area, you can connect the Keyer after converting the footage into Log color space. Use the ‘mergeLog‘ gizmo to merge the footage with the background, preserving more details. Additionally, applying MotionBlur can make it appear more natural.
• Before merging the fire footage over the background, you can merge it with the ‘max’ operation to enhance detail and color in the outline area.

• For thick and strong fire, create a core matte for the fire footage by blurring, increasing contrast, eroding, and inverting the alpha. This will give you a black-colored core matte. Merge the fire footage over it with the ‘plus’ operation.

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Creating Reflections:

• Reflections are crucial for making the scene look natural, especially in scenes with reflective objects such as glass, plastic, or metal. Here are some techniques to create reflections:
  • Re-arrange the fire footage with CornerPin, blur it, and multiply with a low value or mask it into the glass area.
  • Use CurveTool to create average intensity data from the fire footage. This data can be applied to the gain of a Grade node to create a flickering effect.

Heat Distortion:

• Real fire creates heat distortion around itself. To mimic this effect, add Noise around the fire and convert the merged footage into forward u and v for IDistort.

After adding all the environmental effects, merge the fire footage using the techniques mentioned above.