How to pause and resume rendering with Corona Renderer for Cinema 4D?
You can stop a render at any point, or let it end by reaching the rendering limit (pass, noise or time), and then resume rendering from that point later. Both options for resuming rendering can be found by clicking and holding on the Render button in the Corona VFB:
This can also be done in Cinema 4D's native picture viewer under the Corona drop-down menu.
If you have not cleared the VFB, you can start rendering again from the point where it was stopped (whether it was stopped manually, or stopped by reaching a render limit). Corona will then resume rendering, building on the passes that have already been rendered, until it reaches the rendering limit set in the Render Settings.
For example, if your scene had rendered for 10 passes, and you have a Pass limit set of 10, Corona will render for an additional 10 passes, giving a final render with 20 passes. Or if you set a Noise limit, then Corona will render until that Noise limit is reached (note: if the stopped render was already less than that noise limit, then Corona will stop after 1 pass, as the Noise limit has already been reached).
If you now you want to resume rendering at a later time, you can use the Save CXR option from the Corona VFB:
CXR format is an EXR file with extra data used by Corona Renderer that will let it start rendering from where the image left off. The same principles apply as with the Resume Last option, where Corona Renderer will resume rendering until the render limit in the Render Settings is met.
Again, this can also be done in Cinema 4D's picture viewer under the Corona drop-down menu and selecting Dump to EXR.
NOTE: The same scene must be loaded in Cinema 4D before you can use this option, of course!
For information on saving multiple .CXR files, see the following link: How to save a .CXR file from the VFB