Category Archives: Radiance

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 v0.7 – De-noising Radiance Images

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As v0.7 slowly stabilises I’m kicking off the tutorial series with a look at de-noising Radiance images generated with LiVi.

Blender has a nice image de-noising capability that can be used quite effectively with Radiance images. De-noising does not replace higher accuracy analyses – ‘Low’ accuracy settings will still generally produce overall lower luminance and illuminance values, especially in interior scenes – but this is a nice trick to get cleaner images with reduced simulation time.

De-noise comparison

Comparison between the original rpict image and it’s de-noised version

Bug reports and questions can be posted on the Google Group.

Video tutorial is below.

VI-Suite v0.6 – Basic Radiance Simulation

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Sawtooth

Cutaway of a saw-tooth roof and lux simulation

Hello.

I have now uploaded a video tutorial covering the basics of Radiance simulation with the LiVi component of the VI-Suite. The video concentrates on the options within the relevant nodes and the Radiance material options. One thing I should probably reiterate is that a single Blender object can have more than one Radiance material attached as Blender allows you to associated materials with each individual face. The example below shows a red glass sphere with some blue plastic faces.

Radiance materials

Radiance per face materials

 

Also a version from today or later should be used to correspond completely with the options I talk about.

Otherwise I think the video mentions everything else I wanted to say and, as ever, can be viewed 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 – Version 0.4.13 and Radiance Images

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Irradiance falsecolour image

Irradiance falsecolour  image

I have just uploaded VI-Suite 0.4.13 to the download links at http://arts.brighton.ac.uk/projects/vi-suite/downloads. Changes in this version can be seen in the Changelog. One of the main new features of this version is the LIVi image nodes which enables the generation and manipulation of Radiance images for falsecolour metric visualisation and glare analysis.

Images can be generated in parallel on multi-core machines when using OS X and Linux. Unfortunately the methodology employed will not work on Windows.

As ever the tutorial video below explains their operation.

 

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.

VI-Suite v0.4 – Artificial Lighting Simulation

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Lighting simulation of Blender's classroom scene

Radiance visual and falsecolour rendering of Blender’s classroom scene

The VI-Suite can simulate artificial as well as natural lighting. Three main methods are available:

  • Specifying a Radiance light material to mesh elements.
  • Associating an IES file with a Blender lamp.
  • Associating an IES file with a Blender mesh plane to create an array of lights.

IES files, which are text files describing the brightness of a lamp or luminaire from different viewing angles, are released by manufacturers for their specific lighting products and can usually be downloaded from their websites. This gives the opportunity to see how real world products will illuminate a scene visually and with the VI-Suite numerically.

As ever, the video below describes these three methods.

VI-Suite v0.4 – Radiance Patterns

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As of version 0.4.7 the VI-Suite can now use Blender’s UV image mapping system to create image based Radiance patterns. In the example Radiance rendering below an image texture has been mapped to the wall and picture to create a diffuse reflecting Radiance image pattern, and to the window to create a transparent one.

The video tutorial below details the process.