Although the user interface is simple, the algorithms behind the software are very detailed. The following components are involved and explained briefly:
Terrain Modeling
The terrain model incorporates the full effects of solar shadowing, multiple reflections, and re-radiation of geometric features. Each triangular element (or facet) of the terrain has a view factor to background, sky, and other elements. The view factors are calculated by a voxel-based ray-tracing technique which casts rays from each element. Rays which do not encounter another model element "see" default background or sky surfaces. The total radiation on each element will be the net result of emitted radiant energy, incoming solar radiance, and incoming radiant energy (reflected or emitted from other elements).
Starting with a mesh of the area to be modeled, elements of similar terrain are grouped into parts and assigned to the correct terrain type. For example all the elements representing the road are assigned to a road part.
Available terrains and subcategories
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Asphalt: Country road, highway bridge, interstate road, parking lot, runway.
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Concrete: Heavy pad, highway bridge, interstate road, parking lot, runway, sidewalk
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Foliage: Grass (tall, short); trees (coniferous, deciduous, mixed). These all have adjustable degrees of coverage, moisture, and growth factor settings.
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Snow: Fresh, old-dry, rained upon, surface melted, driven on, late in season, tundra, undisturbed.
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Swamp: The swamp model has adjustable dew mass, growth factor, and cover factor.
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Layered: For example, top layer is snow and bottom layer is asphalt.
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Soil: Average, clay, desert sand, gravel, loam, peat, sandy, rocky field. The soil has adjustable moisture settings.
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Water: Clear, turbid. The depth can be adjusted.
Each terrain element is treated as a one-dimensional heat and mass transfer nodal model consisting of 1 to 26 nodes. The temperature of each layer of terrain is computed using a nodal energy balance. The captured physical processes include convection between the air and ground; conduction through the soil layers; mass transfer of moisture in soil; residual mass and flow rates of dew on foliage. The example shows approximately how this works.
Learn More about RadTherm RT
The terrain model incorporates the full effects of solar shadowing, multiple reflections, and re-radiation of geometric features. Each triangular terrain element has a view factor to background, sky, and other elements. The view factors are calculated by a voxel-based ray-tracing technique.
RadTherm/RT provides realistic environmental loading inputs to SNOWPACK, a Swiss snowpack evolution model plugin. SNOWPACK uses meteorological inputs to simulate snowpack layering and snow characteristics.
