Subcamera option in render dialog

[Snapai]

I think it would be useful to be able to define subcameras for rendering, not just preview.

My current scene won't render at 1080p (because it's too much for OpenToonz running on my older computer to handle) - but it will render at lower resolutions.

Even with render tile set to small, it doesn't succeed at full resolution.

I'd like to be able to manually break it up into smaller tiles as well, using the subcamera feature - so I could say, render a quarter of the image at 960x540, in four separate passes, then stitch them together later.

Creating four cameras at half resolution parented to the "main" camera didn't work because I'm using multiplane rendering, and the background shifts based on where the currently-active camera is placed (as it should if it was the main camera).

It seems to me that, since subcamera rendering for preview is already an option, this might be more feasible than any major overhaul of the rendering engine.

Blender actually has this option, though only for the viewport border not additional arbitrarily-defined subcameras:

With the "crop" checkbox dictating whether it should output the entire frame size in transparent with the rendered section placed appropriately, or just images the size of the subcamera region.

I could see this feature being useful to avoid full re-renders in OpenToonz too, if after a test, some small detail needed to be changed, only that part of the image would need to be rerendered and could be pasted over the existing reel (similar to making revisions on a post-it note over an area of a paper drawing)

What do you all think?

[Rodney]

It seems to me that, since subcamera rendering for preview is already an option

Yes, that appears to be the closest thing to what you describe. 

I was just looking for this feature the other day and was surprised I didn't find it.

I was sure it was there.

Camera Settings for Preview do have the option to render from SubCamera so perhaps that code could be borrowed for the final render Camera Settings.

Unless I'm missing something I believe using the Preview render is currently the only way we can render from a SubCamera.

I hesitate to type that because it feels wrong... the setting surely must be there already.  

But if it is I can't find it.

The closest workaround I can find then is to set the Preview Settings to render from the subcamera, Preview, then Right Click and Save Images.

This *should* save the files according to the settings in standard Output Settings (but I need to confirm that part).

Edit:  Yes, the name placed in the standard Output Settings populates the Right Click>Save Images dialog presented with Preview rendering (Shortcut key Ctrl + R).

The only thing that has to be done then is to click the Save button (unfortunately a quick hit of the enter key doesn't accomplish that)

The image shows the option at the bottom of Preview's Camera Settings to render using the SubCamera.

This is accessed via File>Preview Settings

All this to further document what @Snapai has described above.