Category Archives: Sky View Factor

Blender 4.1 and display modes

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Hello.

I had to make a slight change to make the VI-Suite compatible with Blender 4.1 but I haven’t noticed any other problems.

In other news, there are now 2 new experimental display modes for mesh visualisation of results i.e. SVF, Shadow maps and LiVi results. These two modes are Interpolate and Direction and both are exposed as options in the VI-Suite View panel before the visualisation button is clicked.

Interpolate does what it says on the packet and uses matplotlib to interpolate the results on the mesh. There are however limitations to this approach as matplotlib only does 2D interpolation so the sensor mesh should also be 2D. The sensor mesh can be moved and rotated but the transforms should not be cleared in Blender – the results mesh will likely appear in the wrong place if you do.

Another limitation with interpolation is that point numerical visualisation is not available as the results mesh is now a completely new mesh and not based on the sensor mesh. Also, as the interpolation is based on sensor mesh vertex position, then using vertices as the sensor point creates a more accurate interpolation.

Finally, there is a new option in the view panel which is Placement. This is required as Blender cannot convert the matplotlib interpolations into a mesh fully, but has to create overlapping planes. This means a result band forming one plane can be totally obscured by another when it should be visible. The Placement option orders the position of each result band in either result value order or reverse result value order so this may need to be changed in order to see all result planes as they should be. Even then there can be cases where not all result planes are seen, so interpolate should be used with care.

Interpolation

The second display option is for directional results, which at the moment means annual glare calculations (available in the CBDM menu of the LiVi Context node). Any other king of metric will fail, and the code does not currently check there are annual glare results to visualise and will therefore likely cause an error if not. The Direction visualisation will create an arrow for each face/vertex of the sensor mesh. This arrow is coloured according to the legend, and will point in the direction of the chosen view. Point numerical visualisation works as normal. There is one additional option in the View panel which is Arrow size, and this simply changes the size of the display arrow.

Directional

 

EnVi also got some love and can now export the Exhaust fan surface flow component to EnergyPlus, and is available in the Surface Flow node.

If these changes break things, and they might well do so, I have created a branch on the download page for Blender 4.1 that does not include these changes.

Enjoy!

Ryan

VI-Suite v0.6 – Sky View Factor & Shadow Mapping

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SVF calculation

Sky View Factor calculation

I’ve just uploaded a video that introduces the Sky View Factor (SVF) and shadow mapping capabilities of the VI-Suite.

The video also introduces the vi-suite-log file and how it can be used to provide data for some simple custom results processing.

As always I forgot some things in the video. The main thing is that coloured results geometry are placed in their own Blender collection called ‘LiVi Results’ although this video does not cover ‘LiVi’ analysis, but sky view and shadow are lighting related so I place these results within this collection. Once the VI-Suite has created this collection it is important to remember not to put your own geometry in it, as this geometry may then be ignored in subsequent analyses.

Results objects in this collection will be replaced every time a simulation is done, so if you want to keep this geometry for comparative analysis between scenarios move the object out of the ‘LiVi Results’ collection into the scene collection or your own collection.

I’ll also mention that clicking on the heat map analysis itself will bring up a matplotlib display window where you can set some options for the heat map and save that heatmap out to an image.

And finally, the ‘Results out’ sockets of the SVF and shadow mapping nodes can be connected to a VI Chart node for graphing, or the VI CSV node for outputting csv formatted results, but I will cover these two nodes in a separate video.

And finally, finally a github zip download from today or later is required to get the days reported in the VI-Suite log file.

And finally, finally, finally if in solid shading mode I suggest you choose ‘Flat’ shading, which can be found in the ‘Shading’ menu at the top right of the 3D viewport, for the best results visualisation.

I think that’s everything I’ve forgotten. Video is linked below.

VI-Suite v0.6 – Update 3

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Dear all.

I have, I believe, finished adding features to the VI-Suite, for now, and I am now moving into bug-fixing mode. I do not have the access to other computing platforms that I used to have due to the pandemic, so I am interested to hear if there are any activation issues with v0.6 on OS X, Windows and different flavours of Linux.

The zip file of the source code can be downloaded from https://github.com/rgsouthall/vi-suite06/archive/master.zip. This zip file should be installable directly from Blender’s addon preferences window. I have been working purely with Blender 2.83.6 LTS, and while it may work on later Blender versions I am primarily interested in any activation issues with 2.83.6 LTS.

I have not yet finished updating the user manual for v0.6 but for simple sun path, shadow mapping, SVF and LiVi (Radiance) calculations the process is quite similar to v0.4 and the tutorial videos for that release will hopefully give you enough to get started. EnVi (EnergyPlus) and FloVi (OpenFOAM) have changed quite a bit, and I advise waiting for updated documentation before trying those components. I will post here again when a basic manual is available. Tutorial videos will follow after that.

Any bug reports should go in the github page https://github.com/rgsouthall/vi-suite06/issues and general questions on the google group https://groups.google.com/g/vi-suite. Please include in any bug report platform information, the nature and version of the Blender install and any relevant terminal output.

Cheers

Ryan

 

VI-Suite v0.6 – Update

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Dear all.

As some people have been asking what my plans are regarding a Blender 2.8 version of the VI-Suite, I thought I would post an update.

The eagle-eyed amongst you may have noticed that the title of this post skips a version. v0.5 was going to be the last VI-Suite version of the 2.7 series but as 2.8 is now out I decided to roll those changes in to v0.6.

Over the last couple of weeks sun path, wind rose, shadow maps, sky view factor and LiVi have all been, at least in part, transfered over. I am in the process of tranferring EnVi over. There are many bugs remaining, and I would not say v0.6 is ready for usage, but good progress is being made. I’m hopeful that early next year an initial release might be ready.

Once things have stabilised a bit I will post the link to the github repository here.

Regards

Ryan

Blender 2.8 - LiVi

LiVi in Blender 2.80

 

VI-Suite v0.4 – Publication

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An article describing the VI-Suite has been published in ‘Open Geospatial Data, Software and Standards’. As the article is open-access, the full text can be accessed from http://rdcu.be/vRj5. The article was co-authored with Filip Biljecki from TU Delft/National University of Singapore and examines the VI-Suite from a geospatial data perspective.

Southall, R., Biljecki, F.
The VI-Suite: a set of environmental analysis tools with geospatial data applications
Open Geospatial Data, Software and Standards 2(1), Sep 2017, 23
Abstract: 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.

 

As this is the first paper that describes the VI-Suite the article can be used to cite the VI-Suite. The bibtext formatted citation can be downloaded here.

An image from the paper is shown below.

Irrad

Annual irradiance on a building facade

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.