Hi. IES and Accelerad - GPU (Quadro RTX 4000) not being utilsied it seems

[IES user Rad]

Hi there, I have the very latest IES install (VE 2019.0.1.0 Hotfix 1 and accompanying latest 'shared data' file) which i'm led to believe has the Accelerad capabiltiy fully embedded within? I've hence not downloaded Acclerad separately etc, only activated the functionality within IES. Now whilst daylight simulations will run (within the 'Radiance' module within IES), there is little to no discrete GPU usage? Do you perhaps have any tips to hopefully get the most out of, in this instance, an Nvidia Quadro RTX 4000? I also have installs of Daysim, Ladybug and I have a Radiance folder within my C: drive. Are these installs perhaps causing a confusion do you think?

Many thanks for any advice you can provide.

[Nathaniel Jones]

There has already been some discussion of this in this thread, but I'll recap here:

Accelerad uses the GPU for all ray tracing and shading operations, unless you specify the -g- argument (Accelerad version 0.7) or -g 0 (Accelerad version 0.6, which ships with IES last I checked). For RTX cards, it is highly recommended to use Accelerad version 0.7 in order to take advantage of the RTX architecture.

Ray tracing on the GPU is quite fast; it generally only takes several milliseconds of the total Accelerad run. The GPU monitor included in the Windows Task Monitor is intended for monitoring steady usage of the GPU, such as in video games. It is unlikely to register brief GPU activity from Accelerad. If you want to use your GPU more, you could run simulations with larger numbers of rays.

As mentioned here, IES does not use the computer's PATH and RAYPATH variables, so other installations of Radiance or Daysim should have no effect. For details on using Accelerad through the IES interface, you should contact IES technical support. I presume it is possible to manually upgrade IES to use the latest Accelerad version, which is fully backward compatible, by replacing the appropriate files in the IES file structure, but doing so is not officially supported by IES.

Nathaniel

[IES Rad User]

Thank you for the response Nathaniel, it's appreciated. I should initially give my encouragement and say thank you for your efforts with this development work which clearly can be very useful depending on the software it is used with etc.

Unfortunately my experience with IES is that this is not really supported (as they do their other modules) at this point in time. More of a courtesy provision. Perhaps that will change as more users attempt to adopt it also. It is 'free' and not a paid module/feature, perhaps for this reason.

To clarify, from your perspective, there is nothing to do other than 'activate' the Accelerad management feature within IES and subsequently tick the box to use Accelerad, there are no additional downloads for Accelerad files needed, no renaming of Rpict files etc. Nothing other than activate within IES and hope that it works? Also, do you know of any way of determining what version of Accelerad IES is currently running (VE 2019.0.1.0) other than asking IES directly i.e. can the install files be interrogated in some way?

Interesting that you suggest it may be actually be working, only for a very short amount of time. From a laymans perspective, Accelerad is interesting primarily as it is touted (within IES) as having the ability to significantly speed daylighting calculations, but the reality at present, and if behaving as it should, is that this implementation remains a CPU intensive activity (for me) so there is little to no benefit in terms of simulation times. I of course hope that I have just not managed to get the install working properly and there is light at the end of the tunnel, somewhere! But finding a way forward is challenging with little to no understanding of underlying software behaviour...

Thanks once more

[Nathaniel Jones]

When Accelerad starts, it will print a list of the GPUs that it is using to the stderr stream, which allows you to tell that you are running Accelerad rather than classic Radiance. However, I am not aware whether IES allows you to see the program's stderr stream. This is a question for IES technical support.

It is my understanding that Accelerad 0.6 is packaged with IES 2019, and IES users who wish to use it simply need to activate the feature. However, I will reiterate that Accelerad 0.6 does not support RTX cards, and you need to use Accelerad 0.7 for your GPU. I do not know whether IES will attempt to run Accelerad when the GPU present is not compatible. Again, this is a question for IES technical support.

Nathaniel