Multiloaders

This page provides information on a feature called Multiloaders, which you can use to launch 3ds Max with a specific version of Corona, or even multiple instances of 3ds Max at the same time with different Corona versions each. While this is not a common scenario, it may be sometimes useful, for example when setting up render farms, using specific 3ds Max versions with specific Corona versions, or investigating problematic scenes using multiple Corona versions without the need to reinstall Corona multiple times.

Overview

Sometimes you may want to:

• Easily switch between different versions of Corona without the need to manually copy the plugin files into the appropriate 3ds Max installation directories or re-installing Corona
• Run two or more instances of the same 3ds Max version at the same time, each with a different Corona version

Currently, it is not possible to have two or more versions of Corona installed on the same computer for the same 3ds Max version when using our universal installer. But there is a way to overcome this limitation using Multiloaders.

Requirements

Introduction

Starting with Corona Renderer 6, the files CoronaMax20XX.dlr and CoronaMaxUtils20XX.dlt installed by our universal installer into the 3ds Max Plugins folder are not actually Corona Renderer plugins. These files only act as "dispatchers", loading the actual plugin files from another directory.

The actual plugin files are installed into %programfiles%\Chaos\Corona when using the standard installation method, for example:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">C:\Program Files\Chaos\Corona\Corona Renderer for 3ds Max\2025\Corona_Release.dll</span></code>

You can use the instructions in this guide to override this default path to a user-specified one. This way, you can decide which specific files to load when starting 3ds Max (e.g. Corona Renderer 6 plugin files or Corona Renderer 7 plugin files).

Instructions

Step 1: Install Corona

Download and install the newest version of Corona using the standard installation method in our universal installer. If, for any reason, you wish to install an older version, it has to be at least Corona Renderer 6 (the oldest supported version is 31.01.2020 preview).

Step 2: Download and unpack the other Corona version(s) you would like to use

Download the additional versions of Corona you would like to use. They can be stable versions or previews. The oldest supported version is Corona Renderer 5.

Use the "Unpack" option in the installers of each of the additional Corona versions you would like to use. Unpack the plugin files into any desired folders.

See: How to install Corona Renderer manually using the "unpack" option?

Step 3: Set up the environment variable

The name of the variable is:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">CORONA_3DSMAX_<YEAR>_LOAD_PATH </span></code>

Set the variable 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" as your unpacking directory, set:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">CORONA_3DSMAX_2019_LOAD_PATH</span></code>

to

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">C:\Corona Renderer\Corona\Corona Renderer for 3ds Max\2019</span></code>

The environment variable tells the "dispatchers" which of the actual Corona plugins to load.

Here is an example Batch command which does that and starts 3ds Max:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">SET "CORONA_3DSMAX_2019_LOAD_PATH=C:\Corona Renderer\Corona\Corona Renderer for 3ds Max\2019" & START "" "%ProgramFiles%\Autodesk\3ds Max 2019\3dsmax.exe"</span></code>

You can simply save this line as a batch script, run it, and it will start 3ds Max 2019 with the Corona version unpacked to C:\Corona Renderer\Corona\Corona Renderer for 3ds Max\2019. Feel free to edit the script according to your needs, for example by changing the 3ds Max and Corona installation paths or the 3ds Max version.

The environment variable method set by a Batch command only works for the current session. This means that:

• It cannot be used to change the Corona version used in the currently running 3ds Max instance.
• It allows you to have multiple sessions of the same or different 3ds Max versions running with the same or different Corona versions at the same time.
• If you start 3ds Max normally without the multiloaders (e.g. using the desktop shortcut), it will be using the version of Corona currently installed in your system - the one installed using the universal installer.
• It is safe to change the environment variable while 3ds Max is running.

It is also possible to set the environment variable permanently using the options available in Windows:

Open the Start Menu and type "environment", then select "Edit the system environment variables". You can add new environment variables there.

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

Additional Considerations

Using Multiloaders with Chaos Scatter

To load a specific version of Chaos Scatter you can use the same steps as for Corona, but you need to use a different variable, since technically Chaos Scatter is a separate plugin:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">CHAOSSCATTER_3DSMAX_<YEAR>_LOAD_PATH </span></code>

For example:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">CHAOSSCATTER_3DSMAX_2021_LOAD_PATH</span></code>

Corona Renderer 6 and older, 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 can encounter issues with the Corona Converter and Corona Proxy Exporter scripts. This is because the installation path for these scripts is changed. To solve this issue and be able to use the scripts, you need to manually copy the Corona Converter and Corona Proxy Exporter scripts from the directories where they are unpacked:

<code data-v-c2b1f83f=""><span data-v-c2b1f83f="" class="line">C:/Program Files/Autodesk/3ds Max <version>/scripts/CoronaRenderer/</span></code>

Another solution is simply locating the currently needed Corona Converter and Corona Proxy Exporter scripts and manually launching them in 3ds Max, however this is bound to cause some issues such as the Corona Converter button in the Corona Toolbar not working.