Radiance and New MacBook M1!

Hi everyone,
I need a new system (Mac or Windows) for day/lighting design & analysis, which would work with Radiance, Daysim and probably some other simulation tools and platform w/ GUI such as OpenStudio. I’m trying to gather and compare information regarding the best possible hardwares for that purpose!

Does anyone know whether the new MacBook M1 (with non-intel processor) has been tested with Radiance (as well as Daysim and OpenStudio)?


Hi Niloo,

No one on the Radiance “build/dev team” has or has immediate plans to purchase an M1 Mac, so we haven’t any experience running Radiance on the new hardware yet. In theory, binaries built for Intel will “just work” under the translation layer called Rosetta, but I’m old and grouchy and skeptical. THis is a rather good summary of the sitch:

“…power users should take note: The ARM-based Apple M1 is supposed to run legacy x86 software using Rosetta, which could cause adverse effects on performance when running x86 applications. Fortunately, due to its speed, the M1 will still outperform older Intel chips in most scenarios, even with legacy x86 apps. Also, some teething problems are to be expected, as exotic tools and applications might not run out of the box, or they may incur a performance penalty.” (https://www.toptal.com/apple/apple-m1-processor-compatibility-overview)

So it’s the same old same old. The new ARM chips will be awesome if you are all in on Apple and the most obvious applications. The rest of us will endure some degree of brain damage. As much as I’d like to get an M1 Mac and start exploring the new performance as well as start sorting out and benchmarking Radiance under the new hardware, I still like (need) to be able to run Windows VMs on my Mac too, and I think that Windows virtualized on top of x86 on top of Rosetta is going to suck for a while. I dunno, though. I’m glad you brought this up and I’m interested to hear what others out there are thinking in terms of this.

  • Rob

It would be amazing if we had some kind of table that had different hardware platforms as columns and Radiance-related software in rows. Each entry would be an X if an application or tool-set is not supported on a particular platform, or a URL or other reference if it is.

Commonly-used CAD software would be included of course, along with anything else people use in their analyses.

To get started, can folks offer their favorites for software either, (a) incorporates Radiance, or (b) plays well with it?

@Randolph_Fritz4 has been working with Rob Shakespeare and me to update the PDF for “Rendering with Radiance” for free distribution, and the list of related software is something we were hoping to bring up to date.


Hi Rob,

Thanks for your response. Then in theory, it doesn’t look like a good idea to use Apple M1system for Radiance (and probably other Radiance-realated tools). It’s not a good news for Mac users, who are using Radiance-based software for simulation and analysis! I hope somebody would also test this in practice to get a better understanding about the difficulties and possible solutions!


Hi Greg,

I think it’s a very good idea; I’m looking forward to see this table. Recently I was trying to learn more about all the available paltforms and tools for lighting/daylighting/glare simulation and analysis, with their hardware requirements, but the existing online information are not clear, detailed and up-to-date. I think it would be so helpful to anyone in this industry to have a table with the updated information about all the Radiance-related tools (their pros /cons regarding accuracy, flexibility, speed, visualization possibilities, etc.) plus their compatible hardware platforms.

For instance, there are several lighting analysis platforms with graphical user interface such as OpenStudio, Diva fro Rhino, Velux, Autodesk revit (apparently based on previous Ecotect), Dialux, Lightsolve (from EPFL), etc., and it would be so helpful if we could have a comparison of them regarding their capabilities.


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Well, it’s quite possible the compilation of Radiance will work fine on the M1 processor. We just haven’t had the opportunity to try it, yet. I have heard that Apple is making it more difficult for third party developers to create installers, but I don’t know any details. There is nothing to stop someone with a new MacBook laptop from downloading the source and giving it a try. The new unit testing capabilities even provide some level of validation.

Hi all,

I know that Lars was totally over the moon with the M1 and immediately ordered one when it became available. I expect he can give us some performance figures in due time.

Best regards,


There’s a lot of research software that isn’t yet available on the M1, most notably R. GCC isn’t supported on the platform yet and, especially, there is as yet no free native FORTRAN on the platform, which means that some old and important mathematical software will not run natively.

…but if clang can compile Radiance, I think it will run.


while my new toy is still on its way, I will certainly share some
results as soon as it arrives. Yet some assumption-based comments…

I would not expect much trouble about the compilers, you may e.g. get
gcc-builds from http://hpc.sourceforge.net/ right now if you need
optimized native binaries urgently. Given the lack of support for e.g.
openmp or openacc in Radiance, I would not expect too much gains thouth.
In most cases I would recommend to rather keep Apple’s clang, or to
install a development environment through Homebrew or Macports. These
have early native support, but default or fall-back to the
Rosetta2-emulator. I would expect this to be a temporary issue that will
probably be solved within the next few months, and probably the
emulation on the new architecture does not perform much worse than
native on the old one (in particular if you compare to anything affordable).

Other concerns about the “openness” of the system are less related to
the architecture than the operating system. I am e.g. not all that happy
about current x11-support. However, this may become a more familar
problem with legacy libraries - many Linux users are running their
x11-apps not natively any more, too.

Best, Lars.

I am wary of informally released builds on the M1; its floating point error handling is subtly different from the x86 family and this may lead to subtle problems. (See: https://developer.r-project.org/Blog/public/2020/11/02/will-r-work-on-apple-silicon/index.html.)

I believe MacPorts includes an X11 build for the M1. XQuartz does not work.

One open question is how long Apple will support OpenGL and OpenCL. A great deal of research visualization software depends on them.

I am really tired of deliberately introduced incompatibilities.

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The R statistics package uses not only FORTRAN but the assigned special value NA in some of its operations. Neither are used in Radiance, so I don’t foresee any problems there.

Regarding X11 and OpenGL, these are used by some Radiance tools, and it would be great to have a briefer from Lars or whoever figures out how to get Radiance up and running on M1 under the latest version of macOS, explaining the required steps.

We are of course hoping to automate builds and include the M1 architecture in future Radiance packages, but I’m wondering at this point if we’ll have to make separate packages for new and old Apple hardware, which would be painful.

I echo Randolph’s frustration with the apparent disdain Apple holds for legacy software and small-team developers like us. It’s not really a new problem, but one that appears to be accelerating.