From Blueprints to Holograms: AR/MR Technology Implementation in Orange Gate Tunnel Infrastructure Project

MMRDA (Mumbai Metro Regional Development Authority), the client for the Orange Gate Road Tunnel project, expressed discontent with the proposed CAD-based 2D design drawings, particularly in congested area like Western Railways to HN Hospital Road (Zone- 02). These static designs lacked spatial context, locality reference and real-world visual impact, leading to confusion and hesitation in decision-making.

  • Difficulty in understanding the design scale and surroundings
  • Lack of clarity in Site-specific alignments and structures
  • Inadequate alignment between design objectives and real-world conditions
Authored by
Sangeeth Kumar P
Sr. BIM Manager

Initial CAD drawings

Approach/Methodology/Technology used: (AR - MR - VR)

Virtual, Mixed and Augmented Reality

To bridge the understanding gap and improve design communication, the EDRC BIM team adopted the following tools and methods:

  • 3D Modelling: Detailed models of Zone 02 developed in Autodesk Revit

  • Revit 3D Model

  • Visualization: Animated walkthrough and rendered videos using Twinmotion

  • Twinmotion Rendered View

  • Augmented Reality (AR): Used Trimble Connect on tablets and phones for on-site Overlay

  • AR View (Digital Model super imposed on Physical Location)

  • Mixed Reality (MR): Implemented using Microsoft HoloLens 2, enabling immersive visualization at the actual site

  • MR demo on-site using HoloLens 2

  • Site Demonstration: Virtual models were superimposed on the real-world environment to show actual scale, location-specific structures, and context.

  • AR View (Site Demonstration to Client)

“Integrating Mixed and Augmented Reality at the Orange Gate Project has transformed how we validate complex designs. It bridges the gap between 3D models and on-site realities, ensuring better design coordination. This innovation has greatly improved decision-making and client confidence.”

Senthil Kumar Ganapathy

Vice President & Head – EDRC (HCI IC)

Solutions/major actions/innovation initiatives taken:

  • Collaborated with the site team to understand client pain points
  • The BIM team-initiated discussions with the site engineers, planning team, and design coordinators to identify areas where the client (MMRDA) was facing difficulties in understanding the design.
  • Pain points included lack of clarity in spatial orientation, design alignment with existing structures, confusion due to limited views in 2D CAD drawings, and challenges in visualizing real-time site conditions.
  • Joint site visits were conducted to better assess the conditions and gather contextual references (e.g., elevation mismatches, utility clashes, accessibility concerns).
  • The site team played a critical role in facilitating communication with client representatives to align expectations and concerns.

    • Site Visit & Client Discussion for issue resolution

  • Developed accurate Revit models for problematic zones
  • Based on feedback from the site and client, the EDRC BIM team created precise 3D models for Zone 02 using Autodesk Revit.
  • Existing CAD drawings, topographical data, GFC drawings, and site photos were referred to ensure the 3D models captured all architectural, structural, and civil element accurately.
  • The Revit models included parametric components, correct elevation data, and materials, ensuring technical accuracy and alignment with the physical site.
  • Real-time coordination was done with relevant disciplines (structures, utilities, and architectural) to avoid conflicts and maintain model integrity.

    • Revit Model Evaluation

  • Created a compelling animated walkthrough showing proposed structure evolution
  • Using Twinmotion, the Revit models were transformed into immersive walkthrough, animations that illustrated construction sequence, scale, lighting, textures, and site surroundings.
  • The animated walkthroughs included:
    1. Real-world environmental context (sunlight, trees, roads, etc.)
    2. Movement through different parts of the structure
    3. Clear indication of structural volumes, entry / exit points, and cutaway views to show internal layouts
  • Multiple iterations were rendered to align with client feedback and ensure effective storytelling of the design intent.

    • Zone 02 HN Hospital Road Flyover & Opera Junction

  • Deployed AR and MR tools directly at the site for real-time visualization
  • AR (Augmented Reality): Using mobile devices (tablets and phones) with Fologram, the 3D Revit models were overlaid on actual site conditions during site visits.
  • MR (Mixed Reality): Using Microsoft HoloLens 2, stakeholders could view the virtual design while physically walking through the actual site.
  • This hybrid visualization enabled:
    1. Real-world scale matching with digital structures
    2. Better understanding of surrounding constraints (like utilities, obstructions)
    3. Identification of potential design execution challenges ahead of time.

    • AR and MR deployment on-site

“Mixed Reality enabled us to visualize structural assemblies directly on site, which improved precision and reduced rework. It allowed engineers to foresee spatial constraints and validate model placements effectively. The technology has become a key part of our quality and constructability checks.”

Senthilkumar V

JGM – Engineering (Metros)

“Working with AR/MR gave me a new perspective on how our BIM models come to life on site. Seeing our 3D models aligned with the actual construction was both exciting and insightful. It made our work more meaningful, as we could directly contribute to resolving real-time challenges.”

R Bhuvanashri

BIM Asst. Manager (METROS)
  • Presented the models to MMRDA AMC and clarified all queries using real-world overlays
  • A focused presentation session was arranged with MMRDA AMC at the site using MR tools.
  • Our team guided AMC officials through the entire stretch of the critical zones using the HoloLens, providing a detailed explanation of:
    1. Elevation levels
    2. Junction integration
    3. Access roads and service corridors
  • Real-time clarification was provided by toggling between views, changing visibility of structural elements, and adjusting viewpoints within the MR interface.

    • MMRDA AMC Client (Vikram Kumar IAS) Review Session

“The use of AR/MR has redefined stakeholder engagement in our metro infrastructure projects. Visualizing the proposed alignment and structural integration in real-world context accelerated approvals and reduced design ambiguities. It’s a major step toward digital transformation in urban mobility.”

Sadasivam V

GM & Head – Engineering (UT SBG)

“The use of Mixed and Augmented Reality at the Orange Gate Project greatly enhanced design visualization and client communication. 3D models, renders, and animations helped bring designs to life on-site, enabling faster decision-making and approvals. It truly bridged the gap between design intent and physical reality.”

N Gokul Krishna

Senior BIM Modeller
  • Enabled interactive feedback during the session to fine-tune designs immediately
  • Stakeholders could mark points of concern while wearing the HoloLens, which were captured in real-time and converted to comments for the BIM team.
  • Changes such as shifting entry ramps, modifying elevation transitions and correcting structural alignment was captured instantly.
  • Updated versions of the model were shared within 48 hours, reinforcing client confidence in agile and responsive project delivery.
  • This method reduced traditional feedback loops significantly—from weeks to just a few days.

    • Zone 02 Flyover at Lamington Junction

Linkage with Business strategy / objectives:

  • Cross-Functional Collaboration: Enabled seamless coordination between design, execution, and client teams through integrated BIM workflows.
  • Informed Decision Making: Gave stakeholders a clear, real-time visual context to make faster and more confident decisions.
  • Reduction in Rework: Early detection of design concerns through immersive visualization helped eliminate potential rework during execution.
  • Enhanced Stakeholder Engagement: AR/MR demonstrations made complex engineering concepts easily understandable for non-technical stakeholders.
  • Replicable Use Case: Established a successful digital workflow model that can be applied to future urban infrastructure projects.

  • Linkage with Business Strategy

Innovation: Enhanced Site-Level Visualization & Validation

Resource Type Details
Manpower BIM modelers, AR/MR specialists, Site Engineers and
Coordination team
Equipment HoloLens 2, Tablets, Laptops with GPU
Software Licenses Autodesk Revit, Twinmotion, Trimble Connect
External Resources Support from Autodesk / Twinmotion for rendering optimization
  • 1. On-Site Mixed Reality (MR) Design Validation Using HoloLens 2
  • First-time deployment of Microsoft HoloLens 2 at the construction site to enable immersive visualization of 3D models aligned to real-world scale.
  • Allowed MMRDA AMC officials and key stakeholders to "walk through" the digital design directly at the site, helping them experience design elevation, junction integration, and spatial layout in real context.
  • Enabled interactive control – users could hide / show structural elements, change perspectives, and simulate cutaway views in real-time.
  • 2. Augmented Reality-Based Overlay Using Trimble Connect
  • Utilized Trimble Connect app on mobile/tablet devices to overlay Autodesk Revit models on actual site terrain.
  • Supported site engineers in spatially verifying structures, especially where CAD sections lacked clarity.
  • Enabled alignment checks with physical references, enhancing accuracy before execution.

Innovation: Accelerated Coordination & Agile Design Iteration

  • 3. Real-Time Feedback Capture via MR
  • Stakeholders marked issues (e.g., entry ramp alignment, elevation transitions) directly in the HoloLens interface.
  • These annotations were automatically converted to BIM model comments and integrated with ACC Docs for follow-up.
  • This reduced feedback cycles from 1–2 weeks to less than 48 hours, enabling rapid model updates and increased client confidence.
  • 4. Immersive Walkthrough Animations for Stakeholder Buy-In
  • Revit models were enhanced using Twinmotion to generate animated walkthroughs showcasing:
    1. Structural volumes and functional layouts.
    2. Construction phasing and sequencing.
    3. Environmental context including roads, trees, and sunlight conditions.
  • Used during client briefings to improve storytelling and obtain faster design approvals

Benefits derived from the project:

Improvement parameter Tangible benefits Remarks
Productivity 20% reduction in client feedback cycle Faster design approvals
Quality Accurate spatial understanding Reduced ambiguity and
rework
Cost Avoided redesign costs (~5% estimated) Saved rework effort and
redesign man-hours
Delivery Accelerated client sign-off Early clearance enabled timely project execution
Safety Identified potential design-site conflicts Pre-emptive corrections
reduced risk during execution
ESG (Environmental,
Social and
Governance) 		Reduced printing and
documentation 		Promoted digital workflows
Others
(Morale/Employee
engagement etc.) 		Improved stakeholder trust and engagement Boosted morale and team
collaboration

Other intangible benefits:

  • Enhanced confidence of client and consultant teams in digital workflows
  • Boosted internal capability and readiness for future digital delivery
  • Developed a reusable framework for future immersive presentations
Before (Status before improvement) After (Status after improvement)
Designs shared with client were limited to
2D CAD drawings, lacking visual clarity.

Client (MMRDA) found it difficult to
visualize complex tunnel geometry across
Zones 1, 2 & 3.

Design iterations increased due to lack of
clarity and misaligned expectations

Risk of rework and delay in approvals due
to ambiguous interpretation of design
intent.

Divergence between the client’s needs and the proposed implementation strategy.

Site teams faced difficulty in
communicating locality constraints and
real-time site context.

Limited use of digital tools for stakeholder
engagement.

Low confidence from client, resulting in
slow decision-making and project inertia. 		Developed accurate 3D Revit models
representing the real site conditions and
technical detailing.

Used Twinmotion walkthroughs to
simulate construction phasing and
environmental impact.

AR & MR technology enabled overlaying
virtual tunnel models on real site using
HoloLens and mobile AR apps.

Client could now interact with the design
in real scale and context, dramatically
improving comprehension.

Enabled live feedback and on-site
revisions, accelerating the approval
process.

MMRDA AMC appreciated the immersive
experience, leading to instant sign-off on
previously delayed design packages.

Improved collaboration between design,
execution, and client teams with shared
digital environment.

Enhanced L&T’s digital innovation
credentials and strengthened trust with
the client.

Horizontal deployment and Sustenance of the initiative

Horizontal Deployment Sustenance
Metro stations and viaducts Created documentation and SOPs for future AR/MR implementations
Highway interchanges and tunnels Internal training sessions conducted for BIM and site teams
High Rise Buildings requiring real-world visualization Toolkit and demo assets stored in a shared library for easy reuse
Pre-bid stage presentations and client acquisition efforts Encouraged AR/MR implementation in other ongoing infrastructure projects.

Key Learnings from the project:

  • Visualization is not just an output, but a communication strategy
  • On-Site AR/VR demos build trust and shorten feedback cycles
  • Early adoption of immersive tech brings long-term value
  • Coordination between BIM, Site and Client teams is essential for success

“Following the successful implementation of MR in Zone 02, the client has now requested to extend its deployment across all zones of the Orange Gate Project, and the implementation is currently in progress.”

External Recognition:

“The innovation was formally recognized by MMRDA AMC, Mr. Ashwin A. Mudhal, IAS, and Mr. Vikram Kumar, IAS, who appreciated the effort and remarked that such pioneering use of Technology in construction is achievable only by a team like L&T.”

Client Experiencing the 3D Model using Mixed Reality

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