In this short tutorial, we will see two methods to create an animated Streaks glow effect.
Video Transcript
Hello everyone! In this short tutorial, we will see two methods to create an animated Streaks glow effect. The tutorial was recorded using Blender version 4.2 and is aimed at users who already have some familiarity with Compositing.
Topics covered include the Glare nodes, masks, and View Layers, which I have discussed in previous tutorials on my channel. This is a great opportunity to subscribe to the channel and enable notifications if you haven’t already!
The first method produces the effect you’re currently seeing on screen and is technically more accurate, as it applies the Streaks glow to the Glossy reflections of an object. However, the animation created with this method can be less visually pleasing for certain objects, such as the diamond used in this example, because specular reflections can vary significantly depending on the camera angle and lighting.
Now, I’m showing the second result on screen. This second method involves using an invisible object positioned where we want the glow to appear. This object is rendered in a different View Layer from the main scene and then added back in Compositing.
In both cases, the idea behind the node setup is straightforward: isolate the object that should emit the glow and apply a Filter Streaks node, animating the Fade and Angle Offset parameters. This allows you to increase and decrease the glow intensity while simultaneously rotating its rays.
The Fade parameter controls the intensity falloff of the rays based on their distance from the origin point, effectively allowing you to adjust their length.
The Angle Offset parameter, on the other hand, intuitively rotates the rays generated by the Streaks effect.
In both solutions covered in this tutorial, the result of the Glare effect is passed through additional nodes to enhance the glow using techniques discussed in previous video tutorials on this channel. By using the RGB Curve and Exposure nodes, you can fine-tune the intensity of the rays, while the Blur node can be used to slightly soften them for a better visual outcome.
The glow effect is then combined with the original render using a Mix node set to Addition mode.
In both solutions presented in this video, the three parameters animated with keyframes are Angle Offset, Fade, and Addition Factor. Specifically, the Fade and Addition Factor parameters increase from the first frame to the midpoint of the animation and then decrease toward the end. This makes the rays longer and the effect more pronounced at the animation's midpoint.
The value of the Angle Offset parameter, however, rotates by 180 degrees over the course of the entire animation, so no keyframe is set at the midpoint.
This part of the node setup is essentially identical for both solutions. Let’s begin by exploring the node setup that produced the first render shown at the start of this video.
Isolating the object in Compositing is a fairly straightforward operation that can be done in several ways. In this first solution, I assign a value of 1 to the Material Index of the diamond material. Then, I enable both the Material Index Render Pass and the Glossy Direct Render Pass before rendering and moving on to the Compositing stage.
In the Compositing node editor, I retrieve the diamond's mask using an Index Object node set to 1, connected to the Material Index information. I then multiply this mask by the Glossy Direct information, isolating only the Glossy reflections of the diamond.
The issue with this setup is that the rendered object is a diamond, and its specular reflections change significantly during the animation due to the many facets of the diamond and its refractive index. This results in specular reflections that vary greatly between frames.
As a result, while the effect is technically accurate, it can be visually unappealing.
Now let’s look at the second configuration covered in this tutorial, which uses a trick that is not physically accurate but produces a more stable glow in the rendered animation.
First, I add a new View Layer to the project. This View Layer will be used to render an auxiliary object positioned where I want the glow to appear on the diamond.
Next, I move the 3D Cursor to a point on the diamond where I want to center the new object and add the object to the scene. I’m using a simple cube, scaling it down significantly because it needs to be very small to create a compact mask that we can later modify in Compositing.
In this project, the diamond remains stationary, but if the object were moving, you could parent the auxiliary object, which in this case is the cube, to the object being rendered.
I assign the cube a material with an Emission Shader and set its Material Index to 1, making it appear without shading and allowing it to be easily isolated in post-production.
To display only this object in the current View Layer, I first move it to a different Collection from the default one, which I do in the Outliner Editor.
Next, I deselect the checkbox associated with the default Collection and keep only the checkbox for the Collection containing the cube selected.
I then switch to the original View Layer and perform the inverse operation, disabling the rendering of objects in the new Collection.
In the Compositing Editor, I now need to add a new Render Layers node, specifying the new View Layer as the rendering source.
From this node, I extract the Index Material information to create the cube’s mask, which I feed into an ID Mask node with the Index field set to 1, isolating the cube from the rest of the render.
The mask obtained in this way is then fed into the node setup for the Glare effect, and the result of these operations is added to the render from the first View Layer, where the cube was not visible.
That’s it for this tutorial! I hope you found it helpful! See you soon!
