Irradiance Volumes
Diffuse indirect lighting is stored in volumetric arrays. These arrays are defined by the user using Irradiance Volume objects. They control how arrays are placed in the world as well as their resolution.
Lighting is computed at the dot positions visible when the Irradiance Volume object is selected.
Voir aussi
If Ambient Occlusion is enabled, it will be applied onto diffuse indirect lighting. If both Ambient Occlusion and « Bent Normals » are enabled the indirect lighting will be sampled from the least occluded direction and appear more correct.
Référence
- Panneau
- Distance
A probe object only influences the lighting of nearby surfaces. This influence zone is defined by the Distance parameter and object scaling. The influence distance varies a bit, depending on the probe type.
For Irradiance Volumes, the influence inside the volume is always 100%. The influence decays only outside of the volume until the distance to the volume reaches the Distance parameter value (in local space).
- Falloff
Percentage of the influence distance during which the influence of a probe fades linearly.
- Intensity
Intensity factor of the recorded lighting. Making this parameter anything other than 1.0 is not physically correct. Use it for tweaking or artistic purposes.
- Resolution
Spatial resolution for Irradiance Volumes is determined per probe. The local volume is divided into a regular grid of the specified dimensions. One irradiance sample will be computed for each cell in this grid.
- Clipping
Defines the near and far clip distances when capturing the scene.
Avertissement
Clipping distances are applied at the samples positions and not at the grid origin.
- Visibility Collection
In some cases, it is useful to limit which objects appear in the light probe’s captured lighting. For instance, an object that is too close to a capture point might be better excluded. This is what the visibility collection does. Only objects that are in this collection will be visible when this probes captures the scene.
There is also an option to invert this behavior and effectively hide the objects in this collection.
Note
This is only a filtering option. That means that if an object is not visible at render time it won’t be visible during the probe render.
Visibilité
For every grid point a small Variance Shadow Map is rendered. This visibility cubemap is used to reduce light leaking behind occluders. You can tweak the size of this map inside the render settings and tweak the bias and blur factors per grid inside the Probe Properties tab.
- Bias
Reduces self-shadowing.
- Bleed Bias
Increases the « contrast » of the depth test result.
- Blur
Amount of blur to apply when filtering the visibility shadow map. Does not increase runtime cost but has a small effect on baking time.
Blending
The lighting values from an Irradiance Volume will fade outwards until the volume bounds are reached. They will fade into the world’s lighting or another Irradiance Volume’s lighting.
If multiple Irradiance Volumes overlap, smaller (in volume) ones will always have more priority.
Si un objet n’est dans aucun Irradiance Volume, ou si l’éclairage indirect n’a pas été précalculé, l’éclairage diffus de world sera utilisé pour l’ombrer.
Astuce
Lors de l’éclairage des environnements intérieurs, essayez d’aligner des grilles avec la forme de la pièce.
N’essayez pas de mettre trop de résolution dans des zones vides ou des zones avec une faible variation d’éclairage.
You can fix bad samples by adding a smaller grid near the problematic area.
Affichage de la fenêtre
- Influence
Montre les limites de l’influence dans la Vue 3D. La sphère intérieure est là où l’atténuation démarre.
- Clipping
Montre la distance de coupe dans la Vue 3D.