Monthly Archives: June 2017

VI-Suite v0.4 – Version 0.4.11 & Sky View Factor Calculation

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Version 0.4.11 has now been released. This version contains a number of bug fixes and new features,  including the ability to create a sun path with hourly or monthly suns and a new Sky View Factor node. A zip file containing the VI-Suite addon for Blender version 2.7.8 has also been released for Linux 64bit systems. See the changelog page for more details.

The sky view factor (or VI SVF) node operates in a similar manner to the Shadow Map node except that instead of checking if a point can be seen from the perspective of simulated sun positions it is checked if it can be seen from different portions of the sky. The sky can be subdivided into 145 portions (Tregenza) 577 portions (Reinhart 577) or 2305 portions (Reinhart 2305). Accuracy and simulation time increases with each one.

The VI Sky View Factor node can be added through the ‘Analysis Nodes’ menu. An image of the node is shown below. Options are similar as for the Shadow Map node except there is no location input required and no time options, as sky view factor is location and time independent. The ‘Results Out’ socket can be used to save the results to CSV file.

SVF Node

Sky View Factor Node

An example analysis with a 3D city model of the Hague in the Netherlands can be seen below.

SVF analysis

Sky View Factor analysis of the Hague. Model provided courtesy of Filip Biljecki.

 

VI-Suite v0.4 – Radiance Textures

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Normal mapping

Radiance render with multiple normal maps

This tutorial is basically a follow up to the Radiance Patterns tutorial and details how normal maps can be used to specify Radiance textures. Textures in Radiance terminology is a perturbation to the surface normal to give the impression that the surface has detailed physical features. If for example a point on a surface has its normal perturbed towards a light source the point will receive more light than if the surface normal is perturbed away.

Although, like Radiance patterns, textures are not often necessary for numerical lighting simulation, and indeed are ignored if they are on an illuminance sensing surface, they can provide extra realism to visual Radiance renders and there are certain circumstances where they may be useful numerically and/or save time by not requiring the creation of detailed physical geometry.

The video below details the process.