I'm trying to cast shadows from a small (3cm) sphere onto a table surface.

If I place a large object, I get shadows as expected, but below a certain size, I get nothing.

I appreciate that under normal circumstances, shadow map resolution wouldn't allow this level of detail, however, my entire scene is 2x2x3 metres.

I could scale up everything to work around the issue, but that would cause a lot of knock-on issues when it comes to physics, VR and a whole slew of other things.

How can I take the shadowmap area Unity would usually assign to a whole scene and apply it to a single tabletop?

I've tried tweaking the Lightmapping properties for the table, but haven't seen any visible difference.