Fog 3D Node

Unlike the 2D Fog (a post-processing effect on an image), Fog 3D works inside the scene. Each vertex gets a colored attenuation proportional to its distance to the camera - which lets the render correctly combine fog, antialiasing and depth of field.

Classic effects: atmospheric perspective (distant trees turn bluish), cinematic mood (ground fog in a wide shot), integrating forest/mountain packs.

• Effects Library: Tools > 3D > Fog 3D
• Quick add: right-click in the Node Editor → Add Tool > 3D > Fog 3D

• SceneInput (orange) - required. The output of a Merge 3D holding the scene to fog up.
• DensityTexture (green) - optional. A 2D image that locally modulates the fog density. The texture is projected from the camera into the scene, which makes the fog uneven (denser in some places, lighter in others).

Place Fog 3D after the Merge 3D that holds your scene and camera. To see the effect, look through the camera in a 3D viewer (right-click → Camera > [name]) - without the camera view active, the fog doesn't show up unless you enable Show Fog in View.

Enable (default: on)

Turns the effect on or off without fully disabling the node (unlike the red switch on the node, which bypasses it entirely).

Show Fog in View (default: off)

When on, the fog is visible from any point of view, not only through the camera. Handy to see the effect while navigating freely in 3D.

Color (default: white)

Fog color. It is multiplied by the DensityTexture when one is connected. Blue-gray for realistic fog; white for a neutral haze; orange/pink for twilight moods.

Radial (default: off - perpendicular mode)

Switches between two ways of computing distance:

• Perpendicular - distance along the camera axis. Fast, but can create artifacts on the edges of Image Plane 3D nodes.
• Radial - true Euclidean distance. Even density across the whole image, recommended for wide-angle wide shots.

Type (default: Linear)

Choice of falloff curve (see below).

Near Fog Distance (in Fusion units, default: 0)

Distance where the fog starts. Before this distance, there is no attenuation.

Far Fog Distance (in Fusion units, default: 20)

Distance where the fog opacity reaches its maximum. Beyond it, the object is completely lost in the haze.

The Type parameter sets the shape of the attenuation between Near and Far:

• Linear - a uniform progression. The fog builds steadily between Near and Far. A "technical" look, used for depth masks.
• Exp - classic exponential. The fog starts gently then intensifies strongly in the distant area. Closer to real fog.
• Exp2 - squared exponential. Even more pronounced: the near area stays very clear, with a very fast transition to full opacity. Ideal for thin but dense atmospheres (battle in the mist, damp twilight).

Plugging a 2D image into the DensityTexture input makes the fog uneven. The image is projected from the camera into the scene: dark areas (near black) reduce the fog, bright areas (near white) intensify it.

Useful sources:

• An animated fractal FastNoise - rolling sheets of mist
• A Background with a vertical gradient - ground fog only
• A hand-painted mask with the Paint node - fine artistic control

• Atmospheric perspective - build an exterior in depth and fade the distant planes to enhance depth. Blue-gray color + Exp falloff.
• Ground fog - combine Exp2 with a vertical gradient density texture so the mist stops at head height.
• Fantasy / horror - very dense fog (close Far Distance), green or purple color, animated density to create "wisps".
• Depth mask / depth pass - set the fog to white on a black background (no visible scene) to generate a depth mask you can use in post.
• Cinematic transition - animate Far Distance from 100 to 5 between two shots to make the scene "disappear" into the mist.

• If the fog "does nothing", first check that you are viewing the scene through the camera - otherwise enable Show Fog in View.
• Image Plane 3D nodes can produce a halo on their edges in perpendicular mode - switch to Radial to fix it.
• Near Distance must be strictly lower than Far Distance - otherwise the fog behaves erratically (spikes, inverted values).
• Animating Near Distance into negative values (the camera "enters" the fog) gives very cinematic transitions.
• For ultra-realistic fog, combine Exp2 + a FastNoise density + a slight camera move - the wisps look as if the camera were moving through a volumetric atmosphere.
• Since the fog is applied in the 3D scene, it is handled correctly by the Renderer 3D DOF - out-of-focus areas keep the lens character.

The Settings tab has the options shared by 3D nodes.