The Corona Renderer Demo is a fully–functional version of Corona. It can be activated once per computer for 45 days. You can use it to try out Corona Renderer in real projects with no resolution limitations or watermarks, and you can use it for commercial work too. After 45 days, it will still open all projects, but a license purchase or downgrade to an older free build for 3ds Max will be necessary to render them.
To install the demo, download the unified installer and install Corona Renderer. Then run 3ds Max or Cinema 4D, set the renderer to Corona, and hit Render. When a licensing window pops up, select “Activate demo for 45 days”. The demo will usually activate automatically. If not, you will need to copy the request key shown by Corona, paste it here, and copy the activation code back to Corona.