lock/freeze a selection of vertices?

[hike1]

I wonder if it's possible to lock or freeze a certain selection of vertices from translating/scaling/rotating,
say if I were making a 4-piece cave out of a cylinder, I'd want to be able to duplicate the cave cylinder
so I could make variations, yet be able to snap any quarter back into the main cylinder. I'd need to
freeze/lock the seams where the sections meet. I think that's how the Oblivion people did theirs:

http://cs.elderscrolls.com/constwiki/index.php/My_First_Dungeon

[PetrZ]

You can use shape manager to store default position on certain vertex (clusters). It's a little bit tricky, but it should work.

[ThE_JacO]

Store a shape of your "locked" model in absolute mode and connect it to a weightmap.
Paint the lockdown wherever you need it... Done.

You can still alter the position of points in the modeling stack and freeze at will if you need to change something, and paint the lock on and off.
Of course changing the point order will screw things up, but so does in any other app that has explicit locking anyway, and this is still a way more versatile solution for it.

When happy camping ensues you can just freeze the whole load and blast away your weightmap if you want to lean up mesh history.

[hike1]

I'm not familiar with shape manager or weight painting except brief doc skimming, my idea was to make
the 4 seam lines /create/polymesh/extract polys-delete into separate objects then place them on a separate non selectable layer, once I had my caves deformed, merge them back together. Would this be
harder/easier than your method? (keep in mind I'll have to learn weight painting, etc.)

[ThE_JacO]

The shape manager is unnecessary to just save one shape.
Weight painting is as simple as selecting the object and using create>property>weightmap and then hitting W (ctrl+W for the brush properties).
Connecting a shape to a weightmap is just a matter of selecting the shape and using shape>modulate shape with weightmap and clicking the weightmap you created during the pick session.

Minimal manual reading for each step will get you sorted with the fine details, it's definitely doable even with no previous experience using these two simple tools.