Adaptive Subdivision - Concepts

Adaptive Subdivision changes the sampling level of all surfaces based on the electric lighting and/or daylighting beam patterns to create more accurate representations of the beam's interactions with the surfaces. Applying Adaptive Subdivision generally results in more accurate renderings and calculated values, with the necessary requirement of longer calculation times. Without exception, Adaptive Subdivision should be applied to all Full Radiosity Method calculated environments before the final results are outputted from AGi32. Generally speaking, it can be applied as a finishing touch, unless one of the following cases applies:

Source close to illuminated surface (e.g. coves)

In certain circumstances, it may be necessary to apply Adaptive Subdivision during the design process to eliminate "patch leak". For example, a mesh element is divided by an object down the middle of the element (i.e. a cove on a wall, where the wall is the mesh element and the cove is the object). If the element is illuminated from one side of the object, the mesh element may appear equally illuminated on both sides of the object. Adaptive Subdivision can minimize or eliminate this effect.

Source close to calculation points on surface

Adaptive Subdivision may be applied to accurately capture the photometric distribution from a source placed close to a surface. By remeshing the surface, the gradient of light is distributed more finitely and associated Exitance Meter calculation points are accurately calculated.

Adaptive Subdivision Settings

Enable Adaptive Subdivision – Select this check box to activate Adaptive Subdivision. Adaptive Subdivision is deactivated by default. To apply Adaptive Subdivision to Daylight Exterior surfaces, select the Apply to Daylight Exterior Surfaces selection box.

Maximum Subdivision Level – Indicates the level that each element will be divided into for each subdivision loop. The range is from 1 to MAX. The default setting is 3. Level 1 subdivides each element into four smaller elements. Level 2 subdivides each newly created element into four smaller elements. This process is continued until the Minimum Element Area is reached. If the default Level of 3 is used, the Level 3 subdivision loop bridges the transition from small elements to large elements by subdividing the elements in between into triangles. Selecting the MAX level allows surfaces to subdivide to the Minimum Element Area size.

Minimum Element Area – Indicates the smallest element that will be produced by Adaptive Subdivision. The value should be defined on a per-environment basis. The Default value is 0.5. The value is specified in current display units (e.g., square ft or square m).

Element Luminance Threshold – This setting determines the maximum allowable difference in luminance levels between adjacent elements. The Default setting is 1.5.