Ask HN: How do you solve cold start on a three-sided 3d printing marketplace?

I'm building a marketplace that connects 3D designers, local printer owners, and shoppers.

The model: designers upload files, nearby makers fulfill physical orders, shoppers get something printed and shipped locally.

The cold start problem is three-sided (no makers means no physical orders, no designers means no catalog, no shoppers means nobody joins the supply side).

For now, I'm recruiting makers first (I have a small existing community of printer owners from Patreon). But I'm curious how others have thought about how to approach this.

Did anyone here solve a multi-sided cold start without outside capital?