How do I combine masks in DaVinci Resolve?

There are several ways to combine masks in DaVinci Resolve, offering flexibility depending on the desired outcome. Here's a breakdown of common methods:

Method 1: Using Composite Modes (Most Common)

This is the most intuitive and frequently used method for combining masks within a single node.

1. Create your masks: Draw your desired masks using tools like Power Windows or the Magic Mask.
2. Apply masks to the same node: Ensure all masks intended for combination are within the same node in the node tree. Resolve inherently combines masks applied to a single node.
3. Adjust the "Composite Mode": Look in the Power Window settings (or the specific mask's settings if applicable). You'll find a "Composite Mode" dropdown. Common modes include:
   • Add: Combines the masks, showing the areas covered by either or both.
   • Subtract: Removes the area of the second mask from the first.
   • Intersect: Shows only the area where both masks overlap.
   • Difference: Shows areas covered by only one mask and not both.
4. Refine: Adjust the individual mask properties (softness, position, etc.) and the composite mode until you achieve the desired result.

Example:

Let's say you have two circular Power Windows.

• Add: The result will be a shape consisting of both circles combined.
• Subtract: If one circle covers part of the other, the covered part will be "cut out" of the underlying image within that node.
• Intersect: Only the overlapping section of both circles will affect the underlying image.

Method 2: Using Multiple Nodes and Compositing

This method offers more control but requires a slightly more complex node setup.

1. Create each mask on a separate node: Draw your masks using Power Windows or other tools on separate nodes.
2. Connect the nodes sequentially: Connect each node with a mask to the original media node. You might need to use an Alpha Output to isolate only the mask's matte.
3. Use a "Merge" node: Place a Merge node after your masked nodes. The output of your original media goes to the background input (usually the yellow input). The mask's output goes to the foreground input (usually the green input).
4. Adjust the "Composite Mode" in the Merge node: The Merge node also has a "Composite Mode" dropdown, similar to the Power Window settings. Use Add, Subtract, Intersect, etc., to blend the effects of each masked node.

Benefit: This provides more control over how each mask influences the final image, as you can introduce other effects or adjustments between each mask.

Method 3: Using the "Paint Mode" (For very specific needs, like animating subtraction)

As the provided YouTube video suggests, another less common way to create complex masks, is through animating Paint modes. (Relevant portion mentioned in the reference: 0:24-1:59)

1. Create a single Paint mask. Use the paint tool to create the first shape.
2. Animate Subtraction: Change the paint mode to subtract.
3. Animate Level Slider: Activate the keyframe button for the level slider. Bring it down to zero. Go one frame forward and increase the level slider to one. This effectively turns on the subtraction at the desired time.

This method is primarily used for time-based subtractions within the paint tool.

By understanding these different methods, you can effectively combine masks in DaVinci Resolve to achieve precise and creative results for your video editing and color grading projects.