How do these problems of Dimension manifest themselves. The below Diagram explains, most occur because of poor prctise and not recognising problem areas. Besides support points other Hook Up interfaces exist. Module structures can be directly connected to an adjacent Module. Pipework, both Inter Modular and to Piperacks may be connected and for a precise fit the piping interface and its supporting steel work need to be coordinated. The diagrams show how the interferences occur, how they accrue, the cumilative nature of the subject and techniques that may be used ( pre drilled fixing plates, cementing (epoxy) of plates at site.
An important feature for both onshore and offshore foundations and supports is the subject of Dimensional Control. The Diagram  above shows a typical Onshore Installation. A dimensional set off point may be given and all other positions related to that. Both conventional (optical) and lazer rangeing have limitations. Generally these are satisfactory for civil works but can prove a problem when set offs are used  for small tolerance dimensions and in 3 planes. The majority of these problems occur because of the interaction of dimensioning at the site of Manufacture or Fabrication to that of the Construction, Installation and Operation Site of the Modules.
Information can be gained for lazer measuring from typical sites such as:-
https://prezi.com/ziad-lx6nhjv/laser-scanning-dimensional-control/     for Dimensional Control
and
http://www.chockfastgrout.com   for positional cementing

Plate, Mongstad
Plate, Mongstad
Onshore Supports for a Refinery
Besides dimensioning various other techniques are used such as patterns, (usually for smaller items), movable fixings located at site.
a general understanding of Modules 
MODULEitus
C2V
General
General
General
General
Index, Section  3 SUPPORTS Onshore,
C2V
C2V
C2V
Level 1
Level 2
Level 2
Level 1
C2V
C2V
C2V
C2V