Different Rhinos running as separate processes

Simple, but probably not so simple question:

Would it be possible to have Rhino run separate Rhino files as separate processes?

The most obvious reason being, that it is much better if one Rhino file is processing a command or crashing/freezing, it would thereby not be blocking all other Rhino instances.

Much love and thank you,


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Mac forces Rhino to be a multi document application so only one Rhino V6 application can be running at a time.

Interesting… So there is no way to achieve this? I was using ArchiCAD for some time and as far as I can remember it would always create a separate ArchiCAD process for each file. So a new instance of the program would launch.

It’s something Mac OS doesn’t “allow” but may be possible, just Google it…

It’s hard to implement, but something I would love to get Rhino to be able to do some day. Applications like chrome do this with fancy management of child processes.

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Okay that’s what I thought… thanks for the answer! Maybe future macOS release will provide better tools to implement this feature.

Would be really cool if that could be done some day - maybe with RH8.


Just curious, could this feature be on the roadmap for RH8?

To be honest, I don’t think so, but we also don’t yet have a clear roadmap for Rhino 8 just yet - more on that later.

As far as this particular feature is concerned, I can say that we’ve been discussing this for as long as I’ve been involved with Rhino for Mac (8 years now) and it’s one of those “thorny ones.”

But, just to temper expectations a little - as far as Rhino 8 is concerned - there’s already a handful of very large and very technical efforts underway on Mac (Metal support, for example, just to name one), that I have my doubt that we will have the bandwidth to take on another of this magnitude. I hope to be surprised.

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Thanks a lot for the information! Always interesting to hear from “under the hood”. There are many cases where it would be highly practical to have files running as different processes, but I do also agree that there are more important and urgent areas that need to be worked on (Metal implementation, GH responsiveness, etc.)

Thanks again and much success, doing my best to support you guys (if I had lots of money, I would just constantly send money to McNeel to support you guys).

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that is not correct as far as i know, in this case it is Rhino which is preventing the 2nd instance to open since its detecting the serial nr to be running already.

any other application would open with the help of terminal with as many instances as wanted. to be fair i am also running mojave still, but i dont think that has changed.

As far as I know it is also possible to have different Rhino versions running at the same time… at least it was possible with RH5 & 6

currently I am using a combo of Rhino 7 and Rhino WIP as a “workaround”

It is very interesting to hear that this is so complicated, while it is already working with different versions of Rhino…

Here are my three cents about this topic:

  1. I always think twice, if I really want to have multiple files opened with RH7 at the same time - as just a single session crashing, causes all of them to crash. And crashes are not that seldom…

  2. Another slight issue is with Grasshopper. Having two RH7 files with their respective Grasshopper files opened, it takes some time with larger scripts if one clicks back and forth between those two files. Here they are actually sharing the same Grasshopper process and that seem to add some background computation (I guess for the visualization of the GH objects in the Rhino view?).

  3. Furthermore, if one of the Rhinos is executing a longer process (GH script, Rhino command, rendering, etc.), the other Rhino is not usable. So even if the mentioned process only uses one core, one has to wait until that process is finished.

But yeah… I agree, that there are currently more important topics that have to be developed for Rhino. Would be nice if there was a way to achieve this in a not too work-intensive way…



@stevebaer, @dan are there any news regarding this feature? Maybe new (hopefully less tedious) implementation strategies?

Thank you and cheers,

No (and I realize that this is probably another case where “no news is not good news.”) I am aware of some “experiments,” but nothing that would make its way into a WIP any time soon.

Opening multiple instances of an application is common on the Mac. You do it through the terminal:

open -n /Applications/Rhino\ 7.app/

The problem, as has been noted, is that the Rhino license manager does not allow this to take place since it detects another instance being used. This does not happen on Windows, where you can have multiple instances of Rhino open. I emailed support about this and they replied that it should work, but I take it from others here that it does not.

Interesting, seems to work fine for opening a lot of instances of Rhino.

Looks like it is possible to run multiple instances of Rhino and only the license manager is stopping it? Or is this issue more complex @dan, @stevebaer?

Yes, there would be more to do; Rhino for Mac is truly a multi-doc application, unlike Rhino for Windows, so the plumbing for that part is quite a bit different.

As Rhino 8 enters the beta phase, can we expect this feature to be implemented in RH 8.x? I think there is a huge demand for it. Here is another post about it:

(just imagine running a longer Kangaroo sim for example. RH becomes completey unusable for that time period. Not even speaking of crashes that crash all open RH files…)

Could we bump up this feature in the priority list? How big of project would it be?

All the best,

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Unfortunately, this won’t be in the cards for 8.x. It might be something we could consider in 9, but I don’t think we’ve determined our priorities just yet.

Just another usability issue, not necessarily tied to this issue, but probably:

Also only a single GH-session / window can be started. This means, that working on separate spaces is very annoying. Say you are working in 2-3 different Rhino windows and want to use GH in one of them. Then you first have to actually “find” your GH window and bring it to that screen and then click into the Rhino windows you want GH to update to, which also can take a lot of time depending on the script… This is obviously very cumbersome.

Maybe lke seperate RH windows, also seperate GH windows can be allowed? Or it can just be fixed with the seperate process solution anyway…

Also, any chance, that this has shared development work with RIR on macOS?

Thank you and best wishes,