Existing Architectural BIM
Model visible architectural geometry such as walls, openings, floors, ceilings, stairs and other agreed elements.
EXISTING CONDITIONS • RENOVATION • RETROFIT • BIM
Existing Conditions BIM & Existing Building Modeling Services
Build a structured digital baseline for renovation, retrofit, tenant improvement and brownfield projects using available point clouds, CAD drawings, PDFs, photographs, markups and other supplied project information.
Gather
Source Information
Interpret
Existing Conditions
Model
Required Disciplines
Validate
Against Sources
Existing Building Digital Baseline
Renovation Starts with Understanding What Exists Today
New design work on an existing facility depends on a reliable understanding of current building conditions.
Existing Conditions BIM consolidates available scan data, legacy drawings, photographs, markups and project references into a coordinated digital model.
That model can then support design teams, coordination, retrofit planning, constructability review and downstream documentation workflows.
Available Sources → Existing Conditions → Digital Model → Renovation Baseline
A structured starting point
for retrofit,
renovation
and brownfield design.
Existing Conditions Capabilities
Build Existing-State Models Around the Project Need
The model scope can be defined by discipline, building area, required representation, available source information and downstream project use.
Existing Structural BIM
Document visible structural components based on suitable source information.
Existing MEPF Modeling
Model visible mechanical, electrical, plumbing and fire-protection systems where included in scope.
Scan-Referenced Modeling
Develop existing-condition models from supplied point-cloud or reality-capture information.
Legacy Drawing Modeling
Develop models using suitable existing CAD, PDF and legacy documentation.
Renovation BIM Baselines
Prepare existing-state model information for renovation and modernization workflows.
Retrofit Modeling
Support system, equipment and building upgrades with coordinated existing-condition models.
Brownfield BIM
Build project-specific existing-state models for operating or previously developed facilities.
Existing-Condition Drawings
Generate plans, elevations, sections and other agreed drawings from the model.
Existing Building Disciplines
Model the Information Required for the Next Stage
Architecture
Walls,
floors,
ceilings,
openings,
stairs
and visible
building geometry.
Structure
Visible columns,
beams,
slabs,
structural framing
and selected supports.
Mechanical
Existing HVAC
equipment,
ductwork
and visible
mechanical distribution.
Electrical
Visible electrical
equipment,
containment,
fixtures
and selected services.
Plumbing
Visible piping,
fixtures,
equipment
and accessible
plumbing distribution.
Fire Protection
Visible fire-protection
equipment
and distribution
where included in scope.
Existing-Condition Model Content
Represent the Existing Facility at the Required Level
MODEL 01
Building Levels
Establish project-defined
floor and
reference levels.
MODEL 02
Grids
Create or align
building grids
from available
reference information.
MODEL 03
Walls
Model visible
wall geometry
where supported
by source information.
MODEL 04
Floors & Slabs
Represent existing
floor and slab
geometry
as required.
MODEL 05
Openings
Include visible
doors,
windows
and project-defined
openings.
MODEL 06
Structure
Model visible
structural members
where scope
and sources support them.
MODEL 07
Equipment
Represent selected
existing equipment
required for
project coordination.
MODEL 08
MEP Services
Model visible
project-defined
existing building services.
MODEL 09
Ceilings
Represent visible
ceiling planes,
soffits
and selected features.
MODEL 10
Stairs & Ramps
Model vertical
circulation geometry
where required.
MODEL 11
Shafts
Represent accessible
and source-supported
vertical shafts.
MODEL 12
Facility Zones
Organize building
areas,
rooms
or project-defined zones.
Existing-Condition Control
A Detailed Model Is Not Automatically a Verified Record of Every Existing Condition
Existing buildings often contain concealed systems, undocumented changes, inaccessible areas and inconsistencies between historical drawings and current conditions.
The model should therefore reflect the reliability of the available project sources rather than filling unknown conditions with unsupported assumptions.
Visible Condition
Model what
the supplied
source information
clearly supports.
Legacy Information
Use existing drawings
carefully where
current conditions
have not been verified.
Concealed Condition
Do not treat
hidden systems
as verified
without suitable evidence.
Project Clarification
Route significant
source conflicts
for review
rather than guessing.
Existing Conditions Workflow
From Existing Information to a Controlled Digital Baseline
01
Collect
Gather point clouds, CAD, PDFs, photographs, markups and available references.
02
Review
Review source quality, coverage, conflicts and project requirements.
03
Define
Confirm disciplines, areas, model purpose and required representation.
04
Model
Develop the existing-condition model from available project sources.
05
Validate
Cross-check model geometry and information against the intended references.
06
Deliver
Prepare model, drawings and agreed project documentation.
Source Information
Existing-Condition Models Can Combine Multiple Sources
SOURCE 01
Point Clouds
Supplied reality-capture
data can provide
existing geometric reference.
SOURCE 02
CAD Drawings
Existing CAD
can provide
legacy geometry,
dimensions
and drawing references.
SOURCE 03
PDF Drawings
Historical,
record
or archived drawings
can support modeling.
SOURCE 04
Photographs
Project photographs
can assist
interpretation of
visible conditions.
SOURCE 05
Redlines
Supplied markups
can identify
known changes
or revised conditions.
SOURCE 06
Field Notes
Project-provided
notes can support
interpretation of
specific conditions.
SOURCE 07
Equipment Information
Available equipment
data can support
modeling of
selected facility assets.
SOURCE 08
Existing BIM
Legacy model information
can be reviewed
and incorporated
where appropriate.
Model Purpose
Existing BIM Should Be Built for a Defined Project Use
PURPOSE 01
Renovation Design
Provide an
existing-state baseline
for redesign
and modernization.
PURPOSE 02
MEP Retrofit
Support replacement,
rerouting
or upgrade
of existing services.
PURPOSE 03
Space Planning
Provide current
spatial information
for planning
and reconfiguration.
PURPOSE 04
Coordination
Coordinate new
project systems
relative to
existing building conditions.
PURPOSE 05
Constructability
Review existing
geometry,
access
and project interfaces
before construction.
PURPOSE 06
Equipment Replacement
Document existing
rooms,
support areas
and surrounding conditions.
PURPOSE 07
Record Documentation
Consolidate available
existing-building
information
into structured models.
PURPOSE 08
Facility Planning
Support future
digital handover
or facility-information workflows.
Renovation Model Strategy
Existing, Demolished and New Work Should Not Be Mixed
Renovation projects become easier to coordinate when existing conditions, removal scope and proposed work are clearly separated.
A structured model can support that distinction while keeping the existing-building baseline visible throughout the design process.
Existing
Current conditions
retained as
the project baseline.
To Be Removed
Project-defined
demolition
or replacement scope.
Proposed
New design
developed relative
to existing conditions.
Coordination
Review how
new systems
interface with
retained conditions.
Inputs & Deliverables
Existing Information In. Coordinated Digital Baseline Out.
Typical Inputs
- Point-cloud / reality-capture information
- Existing CAD drawings
- PDF / record drawings
- Existing BIM models
- Site photographs
- Field markups
- Project notes
- Equipment information
- Required disciplines / areas
- Project BIM requirements
Typical Deliverables
- Existing-condition BIM models
- Existing architectural models
- Existing structural models
- Existing MEPF models
- Existing floor plans
- Elevations and sections
- Renovation base models
- Coordination backgrounds
- Existing-condition drawing sets
- Project-defined model exports
Existing Conditions QA / QC
Review the Model Against the Available Sources
Existing-condition model quality depends on disciplined use of the source information.
QA should review model geometry, levels, grids, openings, discipline scope, source conflicts and unsupported conditions before delivery.
Source Alignment
Review modeled
conditions against
the intended
project references.
Level Check
Confirm project-defined
level relationships
are represented consistently.
Grid Check
Review model
alignment with
available grid
or coordinate information.
Geometry Check
Compare key
model geometry
with source information.
Scope Check
Confirm only
required project
disciplines
and areas are included.
Uncertainty Check
Avoid presenting
unsupported conditions
as verified
existing information.
Renovation Change Workflow
Use the Existing Model to Control Project Change
STEP 01
Existing Baseline
Establish the
current building
model used
for project planning.
STEP 02
Demolition Scope
Identify project-defined
elements to
be removed
or modified.
STEP 03
Proposed Design
Develop new
work relative
to retained
existing conditions.
STEP 04
Interface Review
Review where
new work
meets existing
building systems.
STEP 05
Coordination
Coordinate project
disciplines against
existing constraints.
STEP 06
Clarification
Route uncertain
existing conditions
for additional
project review.
STEP 07
Model Update
Incorporate approved
project changes
into the
model environment.
STEP 08
Documentation
Produce coordinated
model and
drawing deliverables.
Project Applications
Existing Conditions BIM for Complex Building Workflows
Renovation
Existing-state
digital models
for major
building renovation.
Retrofit
Existing building
information for
MEP,
structural
and equipment upgrades.
Tenant Improvement
Existing architecture
and building-system
backgrounds
for interior redesign.
Industrial Brownfield
Existing facility
modeling for
modifications,
expansions
and equipment changes.
Healthcare Modernization
Existing-condition
models supporting
phased renovation
in complex facilities.
Facility Upgrades
Digital baselines
for maintenance,
modernization
and future planning.
Scope Responsibility
Existing Conditions BIM Does Not Automatically Verify Hidden or Inaccessible Conditions
MEP Global Engineering can create existing-condition models from the supplied project information and visible source conditions.
Model reliability remains dependent on source completeness, point-cloud coverage, legacy drawing accuracy, visibility, field information and the agreed modeling scope.
Licensed surveying, destructive investigation, concealed-condition verification, structural verification, engineering certification and professional approval remain separate project responsibilities unless specifically included through an appropriate scope.
Known Existing Condition
Supported by
supplied source
information
and project scope.
Source Conflict
Should be
identified and
reviewed rather
than silently reconciled.
Hidden Condition
Cannot be
treated as verified
solely from
an external model.
Professional Verification
Remains with
appropriately responsible
project professionals.
Related Services
Connect Existing Conditions to the Full Digital Workflow
Frequently Asked Questions
Existing Conditions BIM FAQs
What is Existing Conditions BIM?
Existing Conditions BIM is the development of a structured digital model representing agreed existing building conditions using available project information.
What source information can be used?
Depending on the project, source information can include point clouds, CAD drawings, PDF drawings, photographs, markups, field notes, equipment information and existing BIM models.
Can architecture, structure and MEPF all be modeled?
Yes. Existing-condition modeling can cover architectural, structural and MEPF disciplines where suitable source information is available and the disciplines are included in scope.
Can the model be used for renovation or retrofit design?
Yes. An existing-condition model can provide a coordinated baseline for renovation, retrofit, tenant improvement, equipment replacement and facility-upgrade projects.
What happens when existing drawings conflict with the point cloud?
Significant conflicts should be identified and handled according to the project's agreed source-priority and clarification process rather than silently assumed.
Does the model confirm concealed conditions?
No. Hidden, inaccessible or concealed conditions cannot automatically be considered verified. Additional investigation or project information may be required.
Existing Building Digital Modeling
Planning a Renovation, Retrofit or Brownfield Project?
Share your available point clouds, CAD drawings, PDFs, photographs, project references and required existing-condition model scope.