Shared Coordinates Process: Overview
Shared Coordinates Process: Overview
Steps
1. Examine
Revit models from design team
2. Examine
site/survey file from civil designer
3. Prepare
site plan in Revit
4. Import
and position survey file
5. Acquire
and publish shared coordinates
6. Verify shared coordinates
positioning
Introduction
Each stand-alone Revit project file
created has a set of internal coordinates which is only used by that
project. In order to overlay different
discipline’s project files and to position buildings relative to a site, a new
set of coordinates must be establish for Revit to correctly reference across
all projects. This is the shared coordinate system. This document is a step by step instruction
of Swinerton Builders’ workflow to applying a single origin and true north
orientation to 2D plans and 3D models, which will be utilized in BIM 360 Glue
for subcontractors and SB Project team to coordinate during shop drawing
development.
Below
define common terms used in this guide:
Project
Internal Coordinate System
The project internal coordinate system
cannot be changed. Revit objects such as
levels and spot coordinates reference to this system. The true origin in Revit is the project base
point. Project North is the view
orientation of plans on a typical construction document sheet.
Shared
Coordinates
This is common work point for
subcontractors and SB project team to use when merging different
subcontractors’ models in BIM 360 Glue.
Shared coordinates for all Revit files will be acquired from civil
survey file. After following the steps
outlined in this guide, SB will distribute to subcontractors a gridline
reference file which contains gridlines matched to those shown on architectural
plans and positioned in the shared coordinate system. Models in BIM 360 Glue will be automatically
and properly aligned in BIM 360 Glue when they are produced in reference to
gridlines that have shared coordinate positions.
This shared coordinates guide is
intended to provide users who are processing design team-authored Revit files
separated by buildings and disciplines for a multi-building project.
DEFINITIONS
OF ACQUIRE AND PUBLISH COORDINATES FROM REVIT HELP
http://help.autodesk.com/view/RVT/2014/ENU/?contextId=HID_GEO_PUBLISH_COORDINATES
Acquire
Coordinates
When you acquire coordinates from a
linked project, the shared coordinates of the linked project become the shared
coordinates of the host project, based on the position of the linked project
instance in the host project. There is no change to the host project's internal
coordinates. The host project also acquires True North from the linked project.
The origin of the linked project's shared coordinates becomes the origin of the
host project's shared coordinates.
When a Revit project acquires
coordinates from a linked DWG file, the World Coordinate System (WCS) of the
selected linked DWG file becomes the shared coordinate system of the host Revit
project, based on the position of the linked DWG instance. The Y axis of the
DWG becomes True North, and the origin of the DWG becomes the origin of the
shared coordinate system of the Revit project.
To
acquire coordinates:
Click Manage tab
Project Location panel
Coordinates drop-down
(Acquire Coordinates).
Place the cursor on a linked model
instance, and click.
The host model file now has the same
shared coordinates as the linked model file. If other loaded linked models
share coordinates with the host model, they also acquire the new coordinates.
Publish
Coordinates
When
you publish shared coordinates from a host project to a linked project, this
changes the linked project. The host project's True North and shared origin are
recorded in the linked project, based on the current position of the linked
instance. This location is now named in both the host project and the linked
project. More than one position of the link can be recorded.
When you publish shared coordinates from
a host Revit
project to a linked DWG, this changes the linked DWG. The origin of the host Revit project’s shared
coordinate system becomes the origin of a new User Coordinate System (UCS) in
the DWG file. The Y axis of the new UCS corresponds to the host project's True
North. You can name the UCS when you publish coordinates. It is not recommended
that you change this name after publishing coordinates.
To
publish coordinates:
Click Manage tab
Project Location panel
Coordinates drop-down
(Publish Coordinates).
Place the cursor on a linked model
instance and click.
Select a named position from the linked
model, and click OK.
See Defining Named Positions.
The linked model file now has the same
shared coordinates as the host model file.