Cvars and Hotkeys

Some of the Look and Optimization Cvars for Unreal Engine's Volumetrics; Unreal Engine's Hotkeys

Scalability

Visuals and Performance

There are some drawbacks when using volumetrics. Even though PVLK is game-ready, it can still have an impact on performance, depending on your machine, and depending on your target audience (Console, Handheld, PC, etc.). I have not profiled a game (yet) while using PVLK's volumetrics, but I have packaged games with it. Since these are just actors, and uses all Unreal Engine based assets, the performance impact would be the same as if you were creating these actors yourself. PVLK just helps to automate, organize and streamline the process. However, the following settings can help with performance.

• PVLK's default for Cast Volumetric Shadows is disabled on the Light Actors. Unreal Engine states this setting has a Medium to Low hit to performance, but on lower end machines, this may be more noticable.
• PVLK's default for Bloom is set to 0, and is set to Standard for the Post Process Volume. Keeping Bloom to a minimum or off can help with performance. Unreal Engine states that keeping the Bloom on Standard vs. Convolution helps with performance. Convolution is stated to be too computationally heavy for games, therefore recommends it be set to Standard if Bloom is to be used, and should be used more for cinematics. I would rate this under Medium to High on being a performance hit.
• PVLK's default for Attenuation Radius is 2048 on Light Actors. This is a tad high, but this seems to be a more realistic area for light to cover. Unreal Engine's default is 1000. Turning this lower will definitely help with performance when you start to add more lights to the level. Sometimes even going as low as 200 may be necessary, especially is the Mobility is set to Movable. The performance impact of this setting is expected to be Medium to High.
• PVLK's default for Volumetric Fog View Distance is set to 2800 for the Exponential Height Fog. Unreal Engine's default is set to 6000. Having it lower can help with the density of the fog and the overall performance. Setting this number higher will make the fog less dense, and can have a slight impact on performance. The expected impact would be Low, but depending on how much you increase and add to it, it can be more around the Medium to High range.

Console Variables (Cvars)

To enter in a cvar, hit the ~ key on your keyboard.

1. r.VolumetricFog.GridPixelSize - default : 16
• What it is - XY size of a cell in the voxel grid, in pixels.
• What it does - The smaller the number, the better the resolution of the volumetrics on the lights, but has a negative impact on performance. The bigger the number, the volumetrics won't look as good, but helps improve performance.
• Performance Imapct - High
Caution - Going below 8 can have a huge impact on your PC, depending on your hardware.
2. r.VolumetricFog.GridSizeZ - default : 64
• What it is - How many Volumetric Fog cells to use in z (I assume it means how many cells in the z-direction).
• What it does - The higher the number, the more dense the volumetrics will be, but has a significant impact on performance. The lower the number, the less dense the volumetrics will be, but helps improve performance. Going higher than 256 can start to noticably impact performance.
• Performance Impact - Medium
3. r.VolumetricFog.LightSoftFading - default : 0
• What it is - Enabled when >0, controls the soft fading of spot and rect light edges in order to make them appear smoother, resulting in less flickering. A value of 1 is a good starting point and it means that fading will be applied over the size of 1 froxel on the screen.
• What it does - Normally set to 0, this setting does what is says, it adds a slight feathering fade to the edges of spotlights and rectlights. This may be necessary to adjust if you notice jagged edges on your rect/spotlights. You should be able to notice a difference at 1 or 2, but you can go much higher if needed. Note: It will dim your volumetrics. Has minimal or no impact on performance.
• Performance Impact - Low or None

Hotkeys

1. While having an element or actor selected in the Outliner, pressing F navigates to it in the level.
2. While having an element or actor selected in the Outliner, pressing Ctrl+B navigates to it in the Content Browser.
3. To view the real-time frame rate in the editor (not during runtime), pressing Ctrl+Shift+H with the viewport selected will show you this.
4. Pressing Alt+P with the viewport selected, plays the level.