I'm attempting to make a sdf storm cloud for real time rendering in Unreal Engine. I want to store sdf values in an 8bit unorm to minimize memory footprint, and in order to do this I've written some simple VEX code in a Volume Wrangle node to clamp distances to a range of +/-8 voxel side lengths, and then remapping to the range. Then I round values such that when converted to an 8 bit unorm, no distance in the vdb is greater than the distance in the pre rounded data.
I'm running into an issue which is causing the far interior region to become inactive when all the voxels in an interior tile are set to zero. As far as I understand, a VDB cannot contain two background values, so the interior region will need to be activated in order to store zeroed values.

Am I thinking about this right? Is what I'm trying to do possible?