is this floating rock about vivec in morrowind the basis for Umbriel? i thnk it was the "ministry of turth" building or something idk.

Yep, as far as I know it was misled by Sheogorath so as to crash into Vivec City, Vivec used his powers to halt the rock in it's tracks but after his disappearance it eventually resumed it's course.

*edit*

Ah I misread, as others have pointed out the ministry of truth isn't Umbriel, it is however the reason that Vuhon worked on the Ingenium.

The Ministry of Truth, Lie Rock, Baar Dau.

And no, it's not directly related to Umbriel.

Umbriel is a part of CV's realm, not Lie Rock.

Their only connection was that the Ministry of Truth drew power from the realm of Clavicus Vile (Where Umbriel originated) in its final days.

Basically, the need to keep it afloat post-Vivec led to the creation of the Ingenium, but that's as far as it goes.

I think they are similer enough to suggest Vuhon was at least inspired a little bit by the Ministry of Truth/Ingenium when he twisted Umbriel from CV.

That's the Ministry of Truth, Which is actually a small moonlet from Oblivion called Baar Dau. I was on a collision course with the Temple Canton, but Lord Vivec was able to halt it. If the Vivec populace are to stop worshiping Lord Vivec however, The moonlet will continue its course and raze the city.

Taken from UESP, Other people may have their own opinion.