How To Choose The Lod

LOD Selection Guide for Scan to BIM: Technical Reference

Table of Contents

LOD Overview

Level of Development (LOD) defines the precision and reliability of a BIM model element — covering both geometry and non-geometric data attributes. In scan to BIM projects, LOD selection determines what the converted model can be used for, how much processing the point cloud data requires, and how much the modeling work will cost.

The American Institute of Architects (AIA) and BIMForum's LOD Specification define six primary stages. Industry standards including ISO 19650 and PAS 1192 establish frameworks for LOD specification and compliance documentation.

LOD Levels at a Glance

LOD Name Geometry Data Primary Use
100 Conceptual Approximate massing/blocks Minimal Space planning, zoning
200 Schematic Generic systems, rough size/shape Basic Early design, budgeting
300 Design Development Accurate dimensions, coordination-ready Moderate Renovation, layout design
350 Construction Detailing Connections, interfaces, supports Moderate+ Clash detection, documentation
400 Fabrication Component-level, shop drawing precision Detailed Off-site manufacturing, installation
500 As-Built / Operational Field-verified, installed conditions Full O&M Facility management, digital twin

Selection Criteria by Use Case

Project Purpose Recommended LOD Rationale
Concept design / space planning 100–200 Approximate geometry sufficient; smaller files
Renovation planning 300 Accurate spatial layout without excessive detail
Structural documentation 300–350 Precise dimensions + connection points
Clash detection (multi-discipline) 350 Interfaces and supports required
Fabrication / prefabrication 400 Shop drawing accuracy needed
Asset / facility management 500 Full metadata + verified as-built conditions

Selection Criteria by User Type

Primary User Recommended LOD Key Requirements
Architects 300–350 Spatial validation, layout coordination
Structural engineers 300–350 Load analysis, connection documentation
MEP engineers 350–400 Routing coordination, clash clearance
Contractors 400 Buildable geometry, installation tolerances
Fabricators 400 Component specs, dimensional precision
Facility managers 500 Equipment metadata, maintenance schedules, serial numbers

Selection Criteria by Space Complexity

Building / Space Type Recommended LOD Notes
Residential, small commercial 200–300 Moderate detail sufficient for design and permitting
Large office, retail 300 Standard coordination requirement
Hospitals, data centers 350–400 Dense MEP systems require interface precision
Industrial / manufacturing 400 Process equipment and structural steel at fabrication accuracy
Heritage / listed buildings 300–350 Laser scan accuracy often limits achievable LOD
FM-ready public facilities 500 Lifecycle and compliance data required

Scan Quality Constraints

Point cloud resolution and registration accuracy set a hard ceiling on achievable LOD.

Scan Quality Achievable LOD Limitations
Low-resolution / single-scan 200–300 Insufficient density for MEP routing, connections, or as-built verification
Mid-resolution, standard registration 300–350 Suitable for most architectural and structural applications
High-resolution, well-registered 400–500 Supports fabrication accuracy and verified as-built documentation

Important: Attempting LOD 400+ from low-quality scans produces models with spatial errors that may not surface until fabrication or installation. Specify scan requirements (resolution, scan spacing, registration tolerance) before fieldwork.

Documentation Requirements

LOD specifications must be formally documented in the BIM Execution Plan (BEP) before modeling begins:

  1. LOD per discipline — Architecture, Structural, MEP specified separately
  2. Element-level examples — Geometry and data expectations for representative components at each LOD
  3. Metadata requirements — Material, manufacturer, performance specs per element type
  4. File naming and deliverable format — Naming conventions, file formats, handover schedule
  5. LOD compliance matrix — Assigned responsibilities per discipline, compliance checkpoints
  6. Modeling intent and constraints — What is modeled, who uses it, accuracy required, known limitations

LOD Decision Matrix

Use this decision flow before committing to a LOD specification:

1. What is the model's primary purpose?
   └── Concept / budget          → LOD 200
   └── Design / renovation       → LOD 300
   └── Clash detection           → LOD 350
   └── Fabrication               → LOD 400
   └── FM / as-built             → LOD 500

2. Who are the primary users?
   └── Architects / Engineers    → 300–350
   └── Contractors               → 400
   └── Facility Managers         → 500

3. What is the scan resolution?
   └── Low                       → cap at 300
   └── Medium                    → up to 350
   └── High, well-registered     → up to 500

4. What does the budget support?
   └── Apply high LOD selectively to the disciplines that require it
   └── Default structural/architectural to LOD 300
   └── Elevate MEP to LOD 350–400 only where clash or fabrication demands it

5. Document in BEP → proceed to modeling

Applying this sequence before fieldwork prevents the most common scan to BIM failure mode: discovering a LOD mismatch after the point cloud has been captured and modeling has begun.

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