Hi Oskar,

> Although I'm no expert on displacement maps, I think they
> are very sensitive to UV-seams.

I'm not sure if that absolutely has to be the case though...

The Ptex stuff for example basically has the equivalent of seams at every polygon edge, but apparently it also incorporates some mechanisms to make the transitions work better.

So I'd think it would be possible to have something similar applied to regular UV map displacement painting.

You may want to try ZBrush or 3D-Coat to see if they handle doing displacement map painting across regular UV seams better than what you are seeing in Modo.

- Michael