Sun Hours - [source code]
Direct sun hours and shadow by ray casting — an interactive preview, not a Radiance simulation.
Input
| Name | Nickname | Description | Type |
|---|---|---|---|
| Context | C | Shading geometry: buildings, terrain, canopies. Meshes, Breps and Surfaces are all accepted and triangulated internally. | Geometry |
| Points | P | Analysis points. | Point |
| Normals | N | Optional point-specific surface normals. When supplied, a sun below a point's own horizon counts as shaded without tracing — a floor cannot be lit from beneath. | Vector |
| Weather | W | Weather record from Download Weather or Open Weather. The sun's position for every hour comes from this file, so nothing else has to be wired to run a study. | Generic Data |
| Start Hour | S | First hour of the period (0-8759). | Integer |
| End Hour | E | Last hour of the period, exclusive. | Integer |
| Timestep | T | Sun samples per hour. 1 is hourly; 10 gives a 6-minute step. An hour moves the sun ~15°, so against a sharp shadow edge an hourly step misses transitions — measured at 3.33 h of error on 245 sunlit point-hours, where a 6-minute step is 12.5× closer (docs/SUN_ANALYSIS.md). Cost is linear: 10 is 10× the rays. | Integer |
| North | Nth | Counter-clockwise degrees from the model's +Y axis to true north (Ladybug's convention). The sun is rotated, not the model. | Number |
| Offset | O | Distance to lift each point off its surface before tracing. Analysis grids usually sit ON geometry that also shades, and without this every point shadows itself. | Number |
| Canopy | Cn | Optional canopy layers from the Canopy component. Vegetation here ATTENUATES the beam and can drop out of leaf seasonally, instead of blocking it like Context. Sun hours become fractional. Slower: attenuating geometry cannot use the any-hit early-out. | Generic Data |
Output
| Name | Nickname | Description | Type |
|---|---|---|---|
| Sun Hours | H | Hours of direct sun at each point. | Number |
| Fraction | F | Sunlit hours as a fraction of the daylight hours considered (0-1). | Number |
| Colors | Col | Point-specific colour ramp over the sunlit fraction, for a mesh or point preview. | Colour |
| Report | R | Rays traced, daylight hours, and elapsed time. | Text |