Delft University of Technology The VI-Suite: a set of environmental analysis tools with geospatial data applications Southall, Ryan; Biljecki, Filip DOI 10.1186/s40965-017-0036-1 Publication date 2017 Document Version Final published version Published in Open Geospatial Data, Software and Standards Citation (APA) Southall, R., & Biljecki, F. (2017). The VI-Suite: a set of environmental analysis tools with geospatial data applications. Open Geospatial Data, Software and Standards, 2(1), [23]. https://doi.org/10.1186/s40965- 017-0036-1 Important note To cite this publication, please use the final published version (if applicable). Please check the document version above. Copyright Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. Southall and Biljecki Open Geospatial Data, Software and Standards (2017) 2:23 Open Geospatial Data, DOI 10.1186/s40965-017-0036-1 Software and Standards SOFTWARE Open Access The VI-Suite: a set of environmental analysis tools with geospatial data applications Ryan Southall1 and Filip Biljecki2,3* Abstract Background: The VI-Suite is a free and open-source addon for the 3D content creation application Blender, developed primarily as a tool for the contextual and performative analysis of buildings. Its functionality has grown from simple, static lighting analysis to fully parametric lighting, shadowing, and building energy analyses. It adopts a flexible, mesh geometry based approach to the specification of calculation points and this has made it suitable for certain types of 3D geospatial analyses and data visualisation. Results: As this is the first academic paper to discuss the VI-Suite, a history of its development is presented along with a review of its capabilities of relevance to geospatial analysis. As the VI-Suite combines the functionality of 3D design software with performance simulation, some of the benefits of this combination are discussed including aspects that make it suitable for the processing and analysis of potentially large geospatial datasets. Example use cases with a 3D city model of the Hague are used to demonstrate some of the geospatial workflows possible and some of the result visualisation options. Conclusions: The free and open-source nature of the VI-Suite, combined with the use of Blender mesh geometry to define calculation points, has encouraged usage scenarios not originally intended by the authors, for example large scale urban shadow and radiation analyses. The flexibility inherent in this mesh based approach enables the analysis of large geospatial datasets by giving the user refined control over the distribution of calculation points within the model. The integration of GIS analysis into a digital design package such as Blender offers advanced geometry/material editing and specification, provides tools such as ray casting and BVH tree generation to speed up the simulation of large datasets, and enhanced visualisation of GIS simulation data including animated city fly-throughs and high quality image production. The VI-Suite is part of a completely open-source tool chain and contributions from the community are welcome to further enhance its current geospatial data capabilities. Keywords: Shadow maps, Radiation maps, Blender, Radiance, Python Introduction well as an intuitive and flexible nodal user interface for the This paper presents for the first time the VI-Suite, a free construction of simulation pipelines. and open-source integrated set of building environmental The VI-Suite uses some of Blender’s in-built function- performance simulation tools that encompasses function- ality to create sun paths and shadow maps, integrates the ality suitable for geospatial analysis. The VI-Suite uses the external applications Radiance and EnergyPlus to carry 3D content creation suite Blender as a host application out lighting and energy simulations and utilises external to provide modelling, rendering and animation capabili- Python libraries to visualise contextual and simulation ties for pre/post-processing of the simulated scenarios as result data [1]. Although many of these capabilities can be found in other software packages the free, multi-platform and *Correspondence: [email protected] 23D Geoinformation, Delft University of Technology, Julianalaan 134, 2628BL open-source nature of the VI-Suite, and all the applica- Delft, Netherlands tions it relies on including Blender, Radiance, EnergyPlus 3 Department of Architecture, National University of Singapore, 4 Architecture and Python, makes the VI-Suite unique and available to Drive, 117566 Singapore, Singapore Full list of author information is available at the end of the article anyone interested in built-environment performance with © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Southall and Biljecki Open Geospatial Data, Software and Standards (2017) 2:23 Page 2 of 13 minimal hardware, platform or cost barriers. In addition, Animation System Blender’s frame based animation sys- the use of an advanced 3D design tool to provide a soft- tem can be used to visualise variant data sets and is also ware framework for a geospatial workflow presents some used by the VI-Suite to specify variant simulation contexts additional advantages which are discussed later in this that enable parametric as well as static analyses. paper. In addition, the Blender interface is very flexible and In addition to its core architectural applications the VI- customisable for different usage cases. This, coupled with Suite has been successfully used to conduct geospatial the Python API, allows plugin (called addons in Blender) data analysis and visualisation. This paper will focus on developers to create embedded custom user interface and these capabilities and begins with a description of Blender display elements. and some of its features that make it suitable as a host application, before going on to describe the VI-Suite in VI-Suite history terms of its aims, capabilities, and history of development. The features mentioned above made Blender an early The paper then proceeds to detail the process of cre- choice as a host application to provide geometry and ating shadow and irradiance maps before finally applying materiality creation and export for the Radiance lighting these methodologies to a geospatial dataset; in this case a simulation suite [9]. Early examples include Brad4 and 3D city model. The integration of the analysis capabilities Radex. of the VI-Suite with a comprehensive digital design pack- Radiance is a set of free, multi-platform and open- age such as Blender is also shown to provide flexible and source tools for the visualisation and calculation of artifi- appealing result visualisations. cial and natural lighting and radiation metrics. Radiance comes with no native user interface and consists mainly Background of a number of executable files, typically run from the Blender command line. This has made the use of pure Radi- Blender1 (Blender Foundation) is a free and open-source ance somewhat problematic for novice users and students 3D application that aims to be a ‘Swiss-army knife’ [10]. Radiance can however accept mesh based geometry for digital content creation. It includes a mesh-based descriptions and can convert OBJ files to native Radi- 3D modeller, advanced materials and texture specifica- ance geometry. The mesh based geometry format used by tion, animation system, a physically based renderer and Blender, coupled with the ability to create custom user adeeplyintegratedPython2 Application Programming interfaces with the Python API, made Blender an appro- Interface (API) amongst other features. Some of these priate choice to act as a Radiance frontend. In these early features have made Blender an increasingly popular host examples Blender acted primarily as a pre-processor i.e. a application for a range of scientific visualisation and anal- geometry/material creator and exporter that could initi- ysis tools [2–5] including GIS data processing3 and other ate the Radiance simulation and visualise the results using GIS related visualisation applications [6–8]. These key Radiance’s native rendering tools. features include: The first component of the VI-Suite, the Lighting Visu- aliser (LiVi), was inspired by these early examples to Mesh based modelling As opposed to a surface (e.g. embed Radiance functionality within Blender. LiVi began Rhino) or solid (e.g. Solidworks) based modeller, geome- in 2009 as a standalone addon for Blender that would try in Blender is primarily stored as a mesh, i.e. geometry convert Blender geometry and materiality to a valid Radi- is composed of vertices, edges and faces. This allows data ance format and initiate the Radiance simulation via to be associated with, and visualised at, specific geomet- additions to the Blender user interface. A key difference ric points, and the distribution of those points is eas- to previous Blender/Radiance integrations was that LiVi ily manipulated by the user. It also means Blender can could then post-process or import numerical results gen- natively import and export a number of common mesh erated by Radiance back into Blender for visualisation. based geometry formats such as OBJ and 3DS with no loss This was achieved by specifying Blender mesh geometry of geometric detail.