Placement of model inside volumetric window?

I am having troubles placing a model inside a volumetric window.

I have a model - just a simple cube created in Reality Composer Pro that is 0.2m on a side and centered at the origin - and I want to display it in a volumetric window that is 1.0m on a side while preserving the cube's origin 0.2m size.

The small cube seems to be flush against the back and top of the larger volumetric window.

Is it possible to initially position the model inside the volume?

For example, can the model be placed flush against the bottom and front of the volumetric window?

(note: the actual use case is wanting to place 3D terrain (which tends to be mostly flat like a pizza box) flush against the bottom of the volumetric window)