can you redefine where the 'floor' of the 3 block limit for json files? my tent is half underground

[gentle pumice]

No
The limit for block models is the block you place it at + 1 block in every direction (including diagonal directions)

what you might be able to do though is to visually "move" the elements by changing the pivot point position via the value fields (NOT the pivot point tool!) for one half at a time

since that doesn't change the position or size values of the cubes, which is what the restrictions limit (both ingame as well as in Blockbench)

[hoary flax]

oh this is big brain thanks for the help!

and this will continue to render over in game?

[marsh pollen]

Or the easier approach, did you consider to use armor stands + display settings?
Allows you to get your model scaled up to be 12x12x12 I believe.

[hoary flax]

the idea right now is to have it as a block in a mod, I'm using mcreator so I also have to double up on their limitations aswell

[marsh pollen]

I mean, it's not as if the block will work properly anyways.
Hitboxes for mouse over don't work beyond 1x1x1, collision boxes don't work beyond -0.5 to 1.5

You'll have to work around that stuff somehow, which is barely possible using MCreator
(the reason why many MCreator mods ignore those hitboxes being broken)
(but even without MCreator it's not easy for such large things)

The default approach for such large stuff, is split it up into multiple blocks, e.g. like doors or beds, which each have a top/bottom / head/feet part.

[hoary flax]

yeah thats fair, they're mostly for decoration anyway so having a broken bounding box isnt too much of a bother

....honestly feel a little silly for not considering to do it as a multiblock

[marsh pollen]

It's your choice, but bugs like broken bounding boxes are one of the reasons MCreator has got such a bad reputation over the years.