Is it possible to fill FastMountainRenderableSeries with pattern set.

Any update on this?

At the moment this is not possible. We do have this working internally for some of the new custom series types in the upcoming v4, which would allow you to achieve the same result, but with a bit more code. Bringing it to the standard mountain series turns out to be much harder than hoped, so this may not be available on the initial release but it is on our roadmap. I don’t have any firm date for a v4 release beyond “soon – I hope”. Keep an eye on the site for announcements.

Regards
David