How to run different versions of Corona Renderer at the same time? (Corona 5 and newer)

Note: this guide can be used to launch Corona Renderer 5 or newer, and requires Corona Renderer 6 or newer installed. The old guide for Corona Renderer 4 and older can be found here: [link]

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 easily switch between different Corona Renderer versions without the need to manually copy the plugin files into the relevant 3ds Max installation directories. 

Currently, it is not possible to have two or more versions of Corona Renderer installed on the same computer for the same 3ds Max version using our universal installer, but there is a way to overcome this using an environment variable.

Step-by-step instructions

To run a different version of Corona Renderer than the currently installed one:

Step 1 - Install Corona Renderer

  1. Download and install the newest version of Corona Renderer using the standard installation method in our universal installer. It has to be at least Corona Renderer 6 (the oldest supported version is 31.01.2020 daily build).

  2. Download the versions of Corona Renderer you would like to use in 3ds Max (it can be a stable version or a daily build, the oldest supported version is Corona Renderer 5).

  3. Use the "Unpack files" option in the installers of the Corona versions you would like to use to unpack the plugin files into any desired folders where they will be stored - see: How to install Corona Renderer manually using the "unpack files" option?

Step 2 - Set up the environment variable

The name of the variable is


and it should be set to the sub-directory where CoronaMax_Release-<YEAR>.dll file is located after the unpacking. 

For example, for Corona Renderer for 3ds Max 2019 and "C:\Corona Renderer" unpacking directory, set:



C:\Corona Renderer\Corona\Corona Renderer for 3ds Max\2019

Here is an example batch script which does that and starts 3ds Max:

SET "CORONA_3DSMAX_2019_LOAD_PATH=C:\Corona Renderer\Corona\Corona Renderer for 3ds Max\2019" & START "" "%ProgramFiles%\Autodesk\3ds Max 2019\3dsmax.exe"

Note: the environment variable method triggered using a batch script only works for the current session. This means that:

  • If you start 3ds Max normally (e.g. using a desktop shortcut), the currently installed version of Corona Renderer will be used. 
  • It is safe to change the environment variable while 3ds Max is running. 
  • It cannot be used to change the Corona version used in the currently running 3ds Max.
  • It allows you to have multiple sessions of the same or different 3ds Max versions running with the same or different Corona Renderer versions. 

You can unpack as many versions of Corona Renderer as you wish and you can select the one you currently need using the method described above. 

To revert to the version which is currently installed using our universal installer, undefine the custom environment variable (if it was set permanently), or just launch 3ds Max normally (if it was set for the current session only). 

When using different versions of 3ds Max and Corona Renderer, keep in mind that:

  • Opening scene files saved with a newer version of Corona Renderer using an older version of Corona Renderer is not supported and the file either will not open at all or will open with various issues (e.g. some features not working, incorrect values, etc).

  • It is not possible to open scene files saved with a newer version of 3ds Max using an older version of 3ds Max (the solution is to re-save the scene in an older 3ds Max format in the File > Save as dialog).

  • Opening scene files saved with an older version of Corona using a newer version of Corona is fine. We sometimes enable legacy switches to keep rendering the same between different Corona versions, so if you would like to try new features, you may need to enable them manually in the newer version.

Corona Renderer 7 and newer, Converter Script, and Proxy Exporter    

If you wish to install Corona Renderer 7 or newer and launch Corona Renderer 6 or older using the methods described in this article you may encounter issues with the Corona Converter and Corona Proxy Exporter scripts. This is because the installation path for these scripts was changed.

To solve this issue and be able to use the versions of the scripts corresponding to the currently used version of Corona Renderer it is necessary to manually copy the Corona Converter and Corona Proxy Exporter scripts from the directories where they were unpacked to C:/Program Files/Autodesk/3ds Max <version>/scripts/CoronaRenderer/

The above is not necessary in cases of:

  • Running different versions of Corona Renderer 7 using the environment variable method (e.g. the final release and a daily build). 
  • Having Corona Renderer 6 installed using the usual way (through the universal installer) and running Corona Renderer 7 using the environment variable method.

Another solution is simply locating the currently needed Corona Converter and Corona Proxy Exporter scripts and manually launching them in 3ds Max.