How to run different Corona versions at the same time?

Sometimes you may want to run two (or more) instances of 3ds Max with different Corona Renderer versions at the same time, or be able to switch Corona-related files (.dll, plugins) without the need to manually copy them into 3ds Max folders.




Full step-by-step guide


Note: this method will work only if you are using exactly the same naming and locations as the ones listed in the below guide. In other cases, you will need to update all of the paths so that they point to the correct locations. 


We will show an example using 3ds Max 2019, but the same steps can be used with any other supported version of 3ds Max.

1. Install the first version of Corona Renderer using standard, automatic installation method in the Universal Installer (we will be using version 3 Hotfix 2).

2. Then remove (either delete or move) all Corona-related .dlr, .dlt, and .dll files from your 3ds Max root folder and from the \plugins\ folder:
  • Corona2019.dlr
  • CoronaUtils2019.dlt
  • Corona_maxHairFur.dll
  • Corona_Release.dll
  • CoronaLib_Release.dll
  • CoronaLibWx_Release.dll
  • CoronaOpenImageIO-1.8.10-v141-Release.dll
  • CoronaOpenVdb-5.0.0-v141-Release.dll
  • CoronaTbb-2018.2-v141-Release.dll
  • CoronaWxWidgets-3.1.0-v141-Release.dll

Note: the above files are valid for Corona Renderer 3 Hotfix 2. In newer versions you may need to remove other .dlr, .dlt, .dll files containing the word "corona".



3. Create directories where the files associated with different Corona Renderer versions will be stored - in the following guide we will be using:
  • C:\corona\version1\ - to store all .dlr, .dlt, and .dll files of the first version of Corona Renderer
  • C:\corona\version2\ - to store all .dlr, .dlt, and .dll files of the second version of Corona Renderer

  • C:\corona\ - to store 1.ini and 2.ini files that tell 3ds Max where the plugin files are located

  • C:\corona\ - to store version1.bat and version2.bat - files that run 3ds Max with different Corona Renderer plugins loaded


4. Run the Universal Installer for the first version of Corona Renderer (in our case version 3 Hotfix 2) and use the "Unpack Files" option.


5. Once the files are unpacked, copy all .dll files from \3ds Max 2019 Plugin\ folder and .dlr and .dlt files from \3ds Max 2019 Plugin\plugins\ folder into C:\corona\version1\


6. Run the Universal Installer for the second version of Corona Renderer (in our case 02.04 V4 daily build) and use the "Unpack Files" option.


7. Once the files are unpacked, copy all .dll files from \3ds Max 2019 Plugin\ folder and .dlr and .dlt files from \3ds Max 2019 Plugin\plugins\ folder into C:\corona\version2\


8. Open Notepad and paste the following code:


[Directories]
corona=C:\corona\version1\
 
9. Save this file as 1.ini in C:\corona\

10. Then in the 2nd line change "version1" to "version2" and save the file as 2.ini in C:\corona\

11. Open notepad and paste the following code:

 

SET PATH=%PATH%;c:\corona\version1
"C:\Program Files\Autodesk\3ds Max 2019\3dsmax.exe" -p "c:\corona\1.ini"
pause


The first line adds the directory in which the desired version of Corona Renderer plugin files are stored to the system variables. It forces 3ds Max to search for the .dll and other files in another directory than the default 3ds Max one.

The second line points to an .ini file with a custom plugin directory - it will search for plugins in that directory. Make sure you are using the correct path to your current 3ds Max installation!
The third line prevents the command line window from closing, this might be helpful if there are any errors. Otherwise you can remove it.

12. Save this file as 1.bat in C:\corona\

13. In the first line, replace version1 with version2

14. In the second line, replace 1.ini with 2.ini

15. save this file as 2.bat in C:\corona\

16. Run:
- 1.bat to start 3ds Max using only the files stored in version1 folder
- 2.bat to start 3ds Max using only the files stored in version2 folder

If you run both .bat files, two instances of 3ds Max should start, each capable of running a different version of Corona Renderer. You can easily see which version is currently running by going to Render Setup > System > About Corona Renerer / Licensing.

After 3ds Max has successfully started you can close each command line window.



Method 2


Another example showing how to quickly swap between different versions of Corona over network has been posted by Martin Geupel aka DeadClown on Corona forums. Additional software required in this guide can be downloaded here.