Good neon is easier to control when the shape and glow are separate. First create a clean line or matte, then build the bloom and composite everything through Merge nodes.
Prepare the shot and the node graph
On the Edit page, isolate the section you need and create a Fusion Clip when appropriate. In Fusion, identify MediaIn and MediaOut before adding anything. A readable graph is much easier to revise later.
Create the neon line with Paint or a mask
Paint is convenient for drawn lines. Create a Stroke, set width and color, then animate Write On so the line reveals along its path. For geometric outlines, a Polygon/Polyline mask can be cleaner than Paint.
- Add Paint.
- Create a Stroke and set Brush Size.
- Choose the core color.
- Animate Write On or the mask length.
Glow: preserve the core and build soft bloom
One oversized Glow often turns a sharp neon line into a blurry blob. Keep a bright narrow core and make the outer bloom softer and wider. Two Glow passes with different settings can be easier to control than one extreme node.
Outline a person or object
For chroma-key footage, a matte can come from Delta Keyer. For normal footage, use an appropriate mask, track or segmentation method. Once you have a matte, derive an edge, color it and feed it into Glow.
Merge the layers cleanly
Composite source, line and glow so each element can be disabled independently. That makes intensity and color changes fast without rebuilding the graph.
Animate and review at playback speed
Offset multiple reveals, add easing and judge the result in motion. A neon effect can look great on a paused frame and feel far too aggressive during playback.
Key takeaway
Neon becomes much easier to art-direct when the line, color and bloom are separate responsibilities in the graph.