Revit Model Management: Best Practice
Revit
Model Management: Best Practice
As technology and system requirements are continually
evolving, Britplas has made every attempt to validate all information. Please
verify and refer to the official Autodesk System Requirements posted on http://www.autodesk.com. Unless otherwise
noted, all information applies only to the Autodesk® Revit® 2010 onwards.
The intent of this document is to convey best practices for
managing a model authored using Autodesk® Revit®. With implementation of BIM
level 2 in the UK and as the design team acclimates to a BIM workflow, the
adoption of a company strategy for model management will become more and more
important. In order to ensure that the model data remains coordinated,
well-structured and efficient Effective management is required. Secondary
benefits include reduced errors; improved consistency between team members; and
gains in production efficiency.
I.
Before the Project Begins
·
It’s important that the hardware on which the
Revit platform is running is up to at least the minimum system requirement set
by Autodesk (See Autodesk website for system requirements).
·
To help users Autodesk has put together minimum
system requirements for Revit 2008 onwards on both 32bit and 64bit systems.
Link: System
requirements for Autodesk Revit products . Also Check your Graphics Card is
on the Autodesk Certified Hardware list. You can check by clicking This Link: Find
Recommended Hardware.
It is always a good idea to close
the program at least once a day (ideally when you take a lunch break) and
before undertaking a memory intensive task, such as rendering, exporting,
printing etc. Autodesk also recommends before performing any of the operations
listed above, performance can be improved by reducing memory usage if you do
the following:
·
Close other applications currently running (but
not being used).
·
Shutting down or restarting your machine at the
end of the day releases system resources.
·
Turn off shadows for all printed views if not
absolutely necessary.
·
Detach local copies from central before printing
and exporting to limit network resources and reduce project chatter between
local and central files (use this tactic with caution because changes
subsequent to detachment cannot be saved to the central file).
·
Images: reduce image size before importing into
Revit.
·
Once you are done using a design option, delete
it.
·
Saving to Central using the "Open - Save
Page".
·
Audit model once or twice a week.
·
Restart Revit over lunch to reset cache.
·
Compacting the file at the end of the day.
·
Overwriting the model with a fresh copy.
·
Pin an element to keep it from moving.
·
Turn off shadows (for all views, and especially
during printing).
·
Link CAD files instead of importing them -
choosing “current view only” when linking.
·
Zoom into the part of the view where you are
working. This will reduce display calculations.
·
Start with generic types (walls, floors, columns
etc.) and get more specific as you go on.
·
Use Move command to move large numbers of objects,
instead of dragging them.
·
Export rendered images to disk, instead of capturing
them inside the project.
·
Import high resolution images into a separate ‘Images’
.rvt file.
·
Perform rendering and walkthroughs in a separate
file and then link the project to that file.
·
Install the newest builds of Revit and service
packs.
·
Switch off Volume Calculations until exports are
required.
·
Minimise number of Levels within the models and
omit levels not used.
·
BIM Manager to perform periodic project/model
health checks and audits.
·
Continuously meet with Revit users, discuss problems
and implement suggestions.
·
Collate and document problems and challenges
(set up a lessons learned register).
·
Update standards and train people on changes and
lessons learned.
·
At the start of new projects, run kick-off
BIM/Revit sessions.
Project Templates should be employed & configured on all
projects to ensure consistent project development, output, functionality and
aesthetics by the BIM Manager/BIM Coordinator. More than one Project Template
may be produced to separate content per project type. Eg. Healthcare,
commercial, residential etc. Templates should include and define the following:
·
Annotation Styles, Dimension Styles, Fonts,
Import/Export Settings, Line styles, Line Weights and Line Patterns. Object
Styles. Tags. Avoid populating project templates with an excessive number of
families that may or may not be useful for every project. Favour a minimal
rather than a comprehensive template.
·
Drafting Views: Consider creating a standard
drafting view for detail development.
·
When setting a template, don’t over load it with
families. Include the 5-10 most commonly used types for System Families (e.g.
Walls).
·
Limit Component Families (e.g. Doors, Windows)
to those that are used on nearly every project.
·
Schedules: Set up and pre-format schedules for
Windows, Doors, etc. so that they will fill themselves out when content is
added to the model.
·
For all preloaded content, ensure that
parameters have been assigned so that schedules and keynotes will fill
themselves out.
·
Titleblocks: Include common sheet sizes (e.g.
A0, A1), company logo, etc. Include examples of sheets that are consistent from
project to project (e.g. Cover sheet, floor plan, ceiling plan, detail sheets
etc.).
·
The standard template only needs to have the
general/standard elements which would be used on most if not all projects. Then
anything else can be added when or if required.
·
Set up appropriate View Template’s for drawing
sheets (e.g. Shaded Elevations/detailed Shop drawing Elevations, Sections).
To increase the productivity of the model the following
should be adhere:
·
Minimise the number of linked or imported files
in a Revit model.
·
Only import ‘cleaned’ and un-exploded AutoCAD DWG
files into Revit, making sure all unnecessary layers and blocks are deleted,
purged, audited beforehand.
·
Think about what’s in the DWG file before you
insert the file into Revit and avoid unnecessary data such as hatching of
AutoCAD specific line-work such as construction lines.
·
Avoid exploding geometry imported from DWG
files, as exploding will creates more elements.
·
Only link essential DWG files into necessary
views. Remove links when not required any more.
·
Switch off visibility of 2D AutoCAD DWG in
perpendicular/elevation views. A 2D DWG file lined to a plan view will show as
collinear lines in elevation, causing performance degradation.
·
Unload all links if they aren’t being used and
reload them when required.
·
When working on large projects think about
breaking the model into separated project models and then linking them into one
single central file.
·
Don’t link or import unnecessary files or
families into your model.
·
When working in a linked file environment use
Wireframe or Shading display modes. Wireframe and Shading modes can be 3times
faster than the Hidden Line or Shading with Edges modes.
·
Unused Views: Name it or delete it. In addition,
use the Close Hidden button to close views that are not currently being edited.
·
Minimise the view depths to avoid showing
unnecessary information.
·
Close hidden views, as any changes to the model
done not only updates the current view but will also update any views affected
by those changes.
·
Turn off shadows in views and when printing
unless required for the final output drawings.
·
When working in a 3D view, don’t have shadows
switched on, it will slow the model down as it will have to redraw the shadows
every time you change the model or move/rotate the view.
·
When navigating within a 3d View, use a section
box to zero in on the area you’re working. This reduces the amount calculations
Revit needs to perform in the background.
·
View Range: Reduce the view range to the minimum
depth necessary to show the desired content.
After creating a new project using the appropriate company
template, a basic set of tasks should be performed to provide direction for the
design team. To create a shared project in Revit, please refer to this link: (Multi-User
collaboration – Revit worksharing). These tasks include:
·
Project Folder/File Structure:
o
Server: Create a folder structure to organize
the locations of the central file, consultants’ files, and any associated files
(e.g. project-specific families, CAD reference drawings, etc.).
o
Workstations: Organize local files in a
consistent manner on users’ machines.
·
Model Position/Extents:
o
Define the project’s position in space by
choosing an origin, whether internal or based on survey data, using project and
or survey base points.
o
Enter location data to establish sun and shadow
information.
o
Define true north and project north.
o
Add levels and grids to represent the expected
scale of the project.
·
Model Organization:
o
Add worksets as needed.
o
Define phases appropriate to the project;
o
If known, set up Design Options for the project.
o
Adjust browser organization to reflect the needs
of the project.
o
Create Shared Parameters if applicable; and
o
Load the appropriate Keynote file if applicable.
·
Model Views:
o
Create appropriate views for the project,
including traditional 2D and 3D views of the model data, 2D drafting views, any
applicable schedules that were not included in the project template, etc.
After your project is shared it can support multiple users.
Users exchange their work by saving to a special file called the Central File. This file is
created automatically the first time you save the project after sharing it.
Autodesk Revit recommends that you do not work in this file unless you are the
only user working on the project. For multiple users, the Central file acts as
the distribution point for publishing work to the rest of the team. Before your
team can work simultaneously on a project, you must create a Central file. Click
here to “See What is the Central file and how do I
create it”.
All users should save their own local copies of the Central
file. You can create a local copy by doing the following;
·
Open the Central file.
·
Choose Save As from the File menu.
·
In the Save As dialog box, give the file a name
and directory location.
When you create or open a local file of a shared project,
you will be able to save two ways:
·
Save – This saves changes to your local file for
safekeeping before you publish it back to the rest of team. Use the save
reminders available in Autodesk Revit Building to make sure your work is saved
regularly.
·
Save to Central – This publishes work by saving
your changes back to the Central file. The Save to Central button on the tool
bar will Save to Central without a dialog box and relinquish all worksets
except for User Worksets. The Save to Central command on the File Menu will
give you a dialog box where you can select what you want to relinquish. All
other team members can then see your changes by selecting Reload Latest from the
File menu. If the Central file has changed since you last saved,
Autodesk Revit will automatically reload the latest versions of your team’s
work. Be sure to save your local file after you have done a save to Central to
ensure that the local and central files are in sync.
When a shared file is first
saved, it creates a directory with your project name followed by “_backup”.
This directory contains the backups for your central file. Successive backup
versions share as much element information as they can, so that they are
incremental, not equal in size to the entire project. DO NOT delete or rename
these folders or files or you will not be able to get to your backups.
Note: You cannot open models stored on a Revit
Server (or central/shared file) using Windows Explorer. You must be in
the Revit application.
The development of an efficient model will require the
design team to strike a balance between modelling complexity and hardware
capability. For example, a 500-room hospital or hotel may benefit greatly from
the use of Groups in Revit; however, these groups may also carry a significant
performance penalty. In general, the following characteristics of a Revit-based
application model can affect performance:
·
Complex geometry
·
Multiple parametric relationships
·
Multiple constraints
·
Linked files
Further recommendations are provided below. Also refer to Autodesk’s Revit Model
Performance Technical Note, or click
here for 2017 revision
·
Parametric families consume more resources than
static families, but they provide flexibility that may reduce the number of
families that need to be loaded into a project—finding a balance is key.
·
Face-based families consume less resources than
those that cut their hosts.
·
It may be unnecessary to model 3D geometry in
all families, especially if the family only appears in one or two orientations
(e.g. plan, elevation). However, 3D geometry may actually be more efficient
than the extensive use of 2D detail elements. Practice both techniques to
optimize families.
·
Use In-Place families sparingly.
·
Create family components instead of in-place
families for repetitive components. When an in-place family is copied, it makes
an entirely new entity each time, as opposed to referencing the type information
from the first instance.
·
Limit the use of detailed/nested/parameterised
families to necessities only.
·
Families require fewer resources than groups.
Use families instead of groups where possible. Groups are very powerful, but
updating large quantities of group instances consumes significant computing
resources.
·
When creating a family in 3D – think, does it
really need to be 3D? If it’s only going to be shown in 2D then you don’t need
a 3D view. Creating a 2D version of a family is 20% smaller than the 3D
version, so if you had multiple families in a project the 3D version would
increase the model size considerably.
·
Minimise over-complicated components –
Remember…KISS! (Keep It Simple Stupid).
·
Complex geometry: Improve performance by
ungrouping and removing the parametric associations of copied objects.
·
Minimise multiple parametric relationships.
·
Multiple constraints: Minimise the constraints
within a model.
·
Don’t use 3D geometry when detailing is
sufficient.
·
Minimise 2d lines, annotation, complexity of
geometry and regions.
·
Cut down on constraining within the model.
·
Unnecessary locking of elements.
·
Use Groups sparingly.
·
When creating detail views, model hatches with
filled regions rather than lines.
·
Limit joined geometry in your model; don’t just
join something – think, does it need to be joined?
·
Levels in Elevation: Avoid using levels to
indicate every vertical reference in elevation (e.g. window head and sill
elevations); such a technique will require a user to hide irrelevant levels in
every elevation and section view. Develop and use Spot Elevation tools to label
these items.
·
Railings: Model railings to provide adequate
detail for general use (elevations, plans), but avoid the temptation to model
all details within the railing. Add two-dimensional details where required
(plans, sections, elevations, details) to fully describe railings.
·
Volumes: Setting the Area and Volume Computation
option to calculate Areas only may improve performance; however, this reduces
much of the analytical functionality of Revit MEP.
·
Consider breaking up the model into multiple
files, especially on large models. For example, if you have a building with
multiple wings, model those in separate models and link them into the central
model.
·
Arrays: Utilize arrays to insert multiple
objects in an ordered fashion, but ungroup and disassociate objects once
inserted if this relationship is no longer necessary.
·
Copy / Monitor: The copy monitor tool may be
employed to synchronize elements such as levels and grids among the design
team. Excessive copy/monitor usage (e.g. all walls) may prove to be
inefficient.
·
Design Options: Utilize design options to
quickly compare alternatives. Once the final design has been determined, delete
unused options to reduce model overhead. For large-scale options (e.g. entire
sections of a building), use separate models instead of design options.
·
Detail Level:
o
Geometry: Until wall, roof, window, and door
types are determined, use the generic versions of these elements, which
incorporate less geometry. Unless material use or other types of analysis will
be applied to the model, consider that a generic wall may be sufficient for
some projects or project areas.
o
Scale: Minimize geometric detail that will be
invisible at the chosen output scale. The necessary level of detail in a given
model can often be conveyed to a team in terms of a commonly understood drawing
scale, such as "Provide detail to a 1:50 level of detail" or some
other commonly employed measure of scale. As much as possible, leverage the
project team's understanding of typical 2D drawing conventions to invest the
correct level of complexity into the model.
·
Detail Lines vs. Model Lines: Detail and model
lines may be used to add information that cannot be modelled efficiently. Use
detail lines to represent information that appears in only one view and model
lines for information that appears in multiple views.
General recommendations, per Autodesk: “Consistent customer
practice is to break up a large model into multiple files of about 160 MB each
for 32-bit Revit or 200 MB for 64-bit Revit, then link together the resulting
project files. Such a procedure will work best if the user can work on one file
while the other links are unloaded for a majority of the time. Engineering
consumers of architectural models may have to maintain one or more constantly
loaded links, which may affect model size estimation and thresholds for those
disciplines.”
The decision to split a model should be made early in the
design process, ideally in the Pre-Design or Schematic Design Phase with all
consultants aware of this decision and its ramifications. Splitting the model
later in the design process adds significant time and cost. Specific conditions
that may trigger a multiple-model project include:
·
Separate buildings (a “campus” project where
each building would be a separate model, linked together on a “master site
plan” project);
·
Collaboration between geographically disperse
project teams (A single building being worked on by multiple offices that are
not on the same WAN);
·
Unusually large files (after all other model
management practices have failed, because of the particular needs or scope of a
project, it may still not be possible to keep the model to a reasonable size);
·
Phased projects where there is a natural and
specific split of the design and/or construction.
Where file size is the primary factor, model splitting
should be considered a last resort and is not to be undertaken lightly. All
model management and modelling best practices methods and procedures should be
exhausted before model splitting is undertaken. If a firm encounters project
types and sizes that require this approach on a consistent basis, I strongly
recommend working in a 64-bit environment with an appropriate hardware
specification in accordance with Autodesk system requirements (or higher). Also refer to Autodesk’s Revit Model
Performance Technical Note, or
click here for 2017 revision.
·
Use Worksets to allow multiple users to work on
a single model at any one time. This is a valuable tool which can help with
workflow as different users take ownership of different elements within the
model, allowing them to edit those elements before relinquishing them back to
the central file.
·
When creating a Workset, leave the Visible by
default in all views option selected. Clearing this option can render the
Workset completely invisible and problematic in multi-discipline workflows
where feature visibility can be of paramount importance.
·
It’s a good idea to create a new local file from
the central model every few days (refer to the above “How Do I Save My Work Once the Project is shared?”).
·
Regularly compact the central and local files to
reduce file size and memory usage.
·
Put linked models on their own workset.
·
Minimise/fix warnings. Less than 10 is ok, more
than 1000 is not!
·
If Revit flags up with a warning as you’re
modelling don’t just ignore it, as later on down the line you may find out that
something has gone wrong.
·
Just like in AutoCAD, it is a good idea to run a
Purge and Audit regularly to help reduce the files and reduce the chances of
the file becoming corrupt.
·
Purge unused families and groups regularly.
The following are recommendations for file maintenance
mirroring those provided by a client with significant Revit project experience.
For small projects, this file maintenance schedule may be largely unnecessary,
while it may need to be accelerated to keep a very large model manageable. Also
note that these maintenance procedures may be applied to files received from
consultants to ensure optimal performance.
Periodic File Maintenance (e.g. every sheet set issue): In
addition to weekly maintenance tasks, perform the following steps:
·
Audit the central file;
·
Create a backup of the central file;
·
Create a new central file; and
·
Have all users create new local files from this
central file.
Every Two Weeks:
In addition to weekly maintenance tasks, perform the following step: Create a
backup of the central file.
Weekly:
·
Audit the central file;
·
Perform a Coordination Review, if using Revit to
maintain coordination with consultants;
·
Perform an Interference Check, if using Revit to
detect collisions;
·
Review and resolve warnings;
·
Delete unused or redundant views;
·
Purge unused elements that will not potentially
be used in later phases of the project;
·
And Compact the central and local files.
Daily:
·
Audit local files upon opening them; and
·
Compact local files when closing them for the
day. Backups and Archives
·
At each issue date, or as required, use the
Detach from Central option to create an independent, archive-ready central
file.
·
Backups can be generated via the same process,
but this is generally unnecessary, as each user’s local file can be considered
to be a backup file. If a central file becomes corrupt, it is often most
efficient to convert the most-recently-saved local file for that project into a
new central file, rather than attempting to recover a backup file that may be
obsolete.
A model Audit should be undertaken on a monthly basis with a
check list and images, by creating a standard Model Audit Template/Report. Make
sure all Revit users are properly trained on how to use Revit, making sure they
follow correct company protocols and best practice method listed above.
References
Autodesk, I., 2016. Autodesk (R). [Online]
Available at: http://revit.downloads.autodesk.com/download/2017RVT_RTM/Docs/InProd/Autodesk_Revit_2017_Model_Performance_Technical_Note.pdf
[Accessed 5 January 2018].
Available at: http://revit.downloads.autodesk.com/download/2017RVT_RTM/Docs/InProd/Autodesk_Revit_2017_Model_Performance_Technical_Note.pdf
[Accessed 5 January 2018].
B. Zollin, 2012. Payette.
[Online]
Available at: https://www.payette.com/technology/ten-ways-to-keep-your-revit-model-speedy/
[Accessed 5 January 2018].
Available at: https://www.payette.com/technology/ten-ways-to-keep-your-revit-model-speedy/
[Accessed 5 January 2018].
DCCADD, 2013. Bim@SG.
[Online]
Available at: https://bimsg.wordpress.com/best-practices/autodesk-revit/
[Accessed 5 January 2018].
Available at: https://bimsg.wordpress.com/best-practices/autodesk-revit/
[Accessed 5 January 2018].
Iftikhar. Udin.
Ismail, 2017. Issuu. [Online]
Available at: https://issuu.com/iuidesign/docs/101_revit_tips-iftikhar_ismail
[Accessed 5 January 2018].
Available at: https://issuu.com/iuidesign/docs/101_revit_tips-iftikhar_ismail
[Accessed 5 January 2018].
I created a small extraction on LoD (Level of Development) and LoD (Level of Detail) which I will be posting shortly. Next Post: LoD Vs LoD lol.
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