<p>From a terminal window, run the command</p>

<pre><code>open -n -a slic3r
</code></pre>

<p>Each time the command is executed, a new instance of Slic3r is created.</p>

<p>As per Carl's note, keep in mind that both instances of Slic3r will be sharing the same configuration files, so it will be safest not to save configuration changes while both are open.</p>

CC BY-SA 4.0
2018-11-05T19:01:01.543Z
See comments about Prefs files under Greenonline's answer
Carl Witthoft
CC BY-SA 4.0
2018-11-05T06:15:38.387Z
2018-11-08T22:24:00.390Z
2018-11-08T22:24:00.390Z
Mark Harrison
<p>You could duplicate the application by clicking on the application and pressing <strong>Command (⌘) + D</strong>, and then run both - although I'm not sure if that would mess with the preferences. I haven't fully tested it, but both instances opened up and worked, seemingly ok.</p>

<p><a href="https://i.sstatic.net/bjNcI.png" rel="nofollow noreferrer" title="Duplicate applications"><img src="https://i.sstatic.net/bjNcI.png" alt="Duplicate applications" title="Duplicate applications"></a></p>

<p>You could even rename them to something other than "Slic3r" and "Slic3r copy" to remind you which application is slicing which model, for example:</p>

<ul>
<li>"TestCube" and "Benchy", or;</li>
<li>"Slic3r-TestCube" and "Slic3r-Benchy", or whatever. </li>
</ul>

<p>However, Mark's answer seems much more elegant. </p>

CC BY-SA 4.0
2018-11-05T19:00:45.147Z
So far as Preferences and whatnot go: that depends on whether Slic3r stores all config files inside its own application folder or in /usr/lib/[whatever] .   However, if one follows Mark H's answer,  you'll guarantee that whatever changes to config or prefs you do in **either** instance will change the only existing prefs. files.   That makes your answer slightly safer!
Carl Witthoft
CC BY-SA 4.0
2018-11-05T08:27:06.043Z
2018-11-05T12:07:41.343Z
2018-11-05T12:07:41.343Z
Greenonline
<p>I am modifying some Slic3r config parameters and comparing the results.  How can I have two instances (or equivalent: I would like to see two model windows with their associated configuration screens) of Slic3r at the same time?  I'm on OS X, but if there is a generic (e.g. within Slic3r) solution that will be preferrable.</p>

CC BY-SA 4.0
2018-11-05T05:01:00.993Z
Mark, The answer to your question is available here: https://stackoverflow.com/questions/47350555
Samveen
CC BY-SA 4.0
2018-11-05T06:18:23.380Z
Thanks Samveen, much appreciated!  I think you should consider that it might be useful here to answer questions related to running 3D printing software, such as slic3r.  There could have been specific slic3r commands or configuration options that are useful for doing this.  Cheers and thanks again!
Mark Harrison
CC BY-SA 4.0
2018-11-05T07:48:25.397Z
@Samveen If you look at [Game plan - What is on-topic?](https://3dprinting.meta.stackexchange.com/questions/276/game-plan-what-is-on-topic) I'm inclined to say that this falls in the category of "Software issues" and should not be closed.
0scar
CC BY-SA 4.0
2018-11-05T08:29:41.553Z
Yes, this could go anywhere including Ask Different, SuperUser...  however, we have an answer now, and everything is upvoted, so even if it is closed, then it will never be deleted :-)
Greenonline
CC BY-SA 4.0
2018-11-05T18:58:13.790Z
@MarkHarrison however, this is very much purely a question of how to handle executables under OS X.  the fact that you are dealing with Slic3r is irrelevant.  Now, if you want to ask how to make Slic3r do two different slices on one object at the same time, then this would be on-topic.
Carl Witthoft
CC BY-SA 4.0
2018-11-08T22:20:38.097Z
@CarlWitthoft, good point... I've updated to reflect that I wish to see two model windows and associated configuration screens, without suggesting or requiring it be done by running multiple Slic3r processes.
Mark Harrison
<slic3r>
How can I run two instances (or equivalent) of Slic3r on OS X?
Mark Harrison
# How can I run two instances (or equivalent) of Slic3r on OS X?

(Asked by: username_0 on 2018-11-05)

I am modifying some Slic3r config parameters and comparing the results. How can I have two instances (or equivalent: I would like to see two model windows with their associated configuration screens) of Slic3r at the same time? I'm on OS X, but if there is a generic (e.g. within Slic3r) solution that will be preferrable.

**Tags:** slic3r

> **Comments:**
> **username_1**: Mark, The answer to your question is available here: https://stackoverflow.com/questions/47350555  
> **username_0**: Thanks username_1, much appreciated!  I think you should consider that it might be useful here to answer questions related to running 3D printing software, such as slic3r.  There could have been specific slic3r commands or configuration options that are useful for doing this.  Cheers and thanks again!  
> **username_2**: @username_1 If you look at [Game plan - What is on-topic?](https://3dprinting.meta.stackexchange.com/questions/276/game-plan-what-is-on-topic) I'm inclined to say that this falls in the category of "Software issues" and should not be closed.  
> **username_3**: Yes, this could go anywhere including Ask Different, SuperUser...  however, we have an answer now, and everything is upvoted, so even if it is closed, then it will never be deleted :-)  
> **username_4**: @username_0 however, this is very much purely a question of how to handle executables under OS X.  the fact that you are dealing with Slic3r is irrelevant.  Now, if you want to ask how to make Slic3r do two different slices on one object at the same time, then this would be on-topic.  
> **username_0**: @username_4, good point... I've updated to reflect that I wish to see two model windows and associated configuration screens, without suggesting or requiring it be done by running multiple Slic3r processes.  

---

## 2 answers

### Answer by username_0 on 2018-11-05. Score: 1 | Accepted answer

From a terminal window, run the command

```
open -n -a slic3r

```

Each time the command is executed, a new instance of Slic3r is created.

As per username_4's note, keep in mind that both instances of Slic3r will be sharing the same configuration files, so it will be safest not to save configuration changes while both are open.

> **Comments:**
> **username_4**: See comments about Prefs files under username_3's answer  

---

### Answer by username_3 on 2018-11-05. Score: 3

You could duplicate the application by clicking on the application and pressing **Command (⌘) + D**, and then run both - although I'm not sure if that would mess with the preferences. I haven't fully tested it, but both instances opened up and worked, seemingly ok.

[![Duplicate applications](https://i.sstatic.net/bjNcI.png "Duplicate applications")](https://i.sstatic.net/bjNcI.png "Duplicate applications")

You could even rename them to something other than "Slic3r" and "Slic3r copy" to remind you which application is slicing which model, for example:

* "TestCube" and "Benchy", or;
* "Slic3r-TestCube" and "Slic3r-Benchy", or whatever.

However, Mark's answer seems much more elegant.

> **Comments:**
> **username_4**: So far as Preferences and whatnot go: that depends on whether Slic3r stores all config files inside its own application folder or in /usr/lib/[whatever] .   However, if one follows Mark H's answer,  you'll guarantee that whatever changes to config or prefs you do in **either** instance will change the only existing prefs. files.   That makes your answer slightly safer!  

---

