This is possible to do using our CEXR file format, which unfortunately has some flaws right now. We are however close to releasing a fix, which will release its full potential.
Here are the instructions:
1. You have to make sure that the render farm supports saving to CEXR. This file format is available in the Save as dialog, just like jpg and other ones.
2. If the file is saved correctly, you will need to rename it from .CEXR to .EXR - this is just about changing the extension name, no modification to the file itself is required
3. Then take this EXR file and load it into Corona VFB by using the "Resume from file" option in Scene tab. You have to make sure that the scene which is currently opened in your 3ds Max is exactly the same file which was rendered.
4. You can either stop the rendering manually right after the image appears in the VFB, or you can use time limit of 1s. If all went fine, you should be able to adjust LightMix, bloom&glare, and other post processing options.
In the future releases we will make this process much more convenient. There will be also a standalone tool, which will allow loading CEXR files and tuning them just like in Corona VFB, but outside of the host application (e.g. 3ds Max).
