Smoke & Fog Documentation
Last updated
Last updated
Smoke Pack Documentation
Below We Explain The Exposed parameters that you could use to modify the Particles behavior easily:
1) Color: Uses a Color Curve which enables you to tint with gradient driven by the age of the particle.
2) Lifetime: Controls how long or quick the duration of the particle. A greater range of min max parameter could reduce the pattern repetitiveness. MaxLifetime MinLifetime
3) Scale: Controls the size in a random range. Utilize the scale randomization to break the shape. MaxScaleSprite MinScaleSprite 4) SpawnRadius: Controls the spawn initial location in a radius metrics.
5) SpawnRate: Controls the spawn rate of the particle per every second.
Parameters on the material instances are also available for the smoke shading flexibility. Control necessary shading controls such as alpha exponent, exposure, values and colors using the following:
1) AlphaPower: Controls the opacity exponent. Use it whether to increasing the negative spaces on your texture or increasing the overall density.
2) ColorPower: Controls the color exponent of the blending of Color1 and Color2
3) DepthFade: is used to hide unsightly seams that take place when translucent objects intersect with opaque ones.
Exposure: Controls the overall texture brightness
4) MotionVector_Intensity: Controls the motion vector distortion intensity. As much as possible leave the default value, to avoid any weird artifacts.
5) NormalFlatness: Controls the normal intensity
Textures included in the EnvironmentSmokes folder are native 4k which in fact could be expensive for realtime vfx for games. But could be very useful for cinematics to maximize the quality.
In order to change the texture Max In-Game so to make it game ready.
Go in texture details, search for Maximum Texture Size. It defaults to 0. You can set it to 512 or 1024 (Make sure it is power of 2) depending on your needs.
It is always better to use polygon rather than overdraw by default.
Above: Uses a spherical cut out, which remove the excess overdraw from the edges. Below: Default overdraw of a translucent particle regardless of the visual.
The Smoke Pack comes with the cutout feature already. In case you have to modify it further you can access it in SpriteRenderer -> Cutout.
Firstly, find the BP_PlumeSmokeSpline_01
The parameters for the blueprint are the same ones that we covered above, utilize them to modify the look and feel of your smoke plumes. Once you drag the blueprint, there is already a default template provided.
A particle that follows the spline position starting from the bottom to top. You can add additional spline points by right clicking the spline gizmos to add more spline points.
There are also various templates provided. All you have to do is to copy the parameters from the Niagara systems (Pictured Below) into the Blueprint. Utilize the entire smoke library and parameters covered above to create a vast array of variations.
The package contains two fog card versions:
A spritesheet based effect that loops infinitely. Great to use to add movement to your scene.
A single image texture that should be used for environmental effects. Use these to optimize performance and when movement is too hard to perceive (For example distant mountain fog)
Simply drag and drop the NS_Fogcard (Pictured Above)
And you’ll get the following as the default effect:
In order to modify the Niagara System to create a variation. Modify the provided parameters (Pictured below) To achieve your desired result.
AnimationSpeed: The effect has a given motion vector map, so you could use slow motion to the effect with less artifacts. AnimationSpeed is being used to retime your sprite sheet.
Changing the Fog Material
FogMaterial: Simply click the dropdown button (Pictured below) and select one of the materials to change the look and feel of your fog cards.
IsCameraFacing: Enable this if you want to make the effect face the camera at all times. Some of the effects specifically those rectangular in shape will look weird in camera facing mode. In these cases you can disable it.
Opacity: General alpha opacity of the texture
Power:
Lower Power: Creates a denser, more opaque fog. The negative spaces (like gaps between objects) become more pronounced, as if the fog is "eating away" at the edges.
Higher Power: Creates a lighter, less dense fog. The negative spaces are less pronounced, and the fog appears more subtle.
Think of it as a knob to adjust the "fogginess" level
ScaleXY: The main scale control for the effect. Adjust it to scale the fog cards to fit your needs.
SpriteRotation: Controls the rotation of the effect
The fog cards are created to be a single spawn effect. In this case we don’t have to worry about the overdraw stacking. However when you populate the scene with many fog cards we recommend to reduce the empty spaces left by the textures using cutouts:
With Cutout
Without Cutout
You might notice some unusual shading with your fog, especially when disabling the camera-facing feature of the sprite. This can be caused by the fog material's default lighting mode, "Volumetric Directional".
This mode calculates lighting based on directionality and takes the material's normal into account, which can improve shading but also lead to unexpected results in certain lighting setups.
To fix this, you can simply switch the fog material's lighting mode to "Volumetric NonDirectional".
This is a simpler, cheaper alternative that doesn't take the material's normal into account, which can help to resolve any odd shading issues you're experiencing.
Example of a lighting issue looks is pictured below
