Historic Peninsula Hotel Project: HBIM and Digital Documentation

Project Summary

This precise survey work was carried out as part of the hotel conversion project for a 19th-century building with Grade 1 historical monument status in the heart of Istanbul. Combining laser scanning and photogrammetry (Drone & Terrestrial) methods, point cloud data with ±2mm accuracy was obtained. From this data, a LOD 400 level HBIM (Heritage BIM) model and stone-by-stone survey drawings suitable for Conservation Board approval were produced.

Project Scope and Challenges

Digital Twin of Cultural Heritage

Our client requested complete and millimeter-accurate documentation of the existing condition (as-is) for the restoration project to receive approval from the Conservation Board.

Key Challenges:

1. Complex Geometry: Inability to measure facade decorations, buttresses, and vaulted passages with traditional methods.
2. Structural Deformations: Detection of wall curvatures and ground settlements formed over centuries.
3. Access Restrictions: Areas on roof and towers where human access is risky.

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Technology and Methodology Used

"Hybrid Data Collection" methodology was followed in the project. Terrestrial laser scanners and UAV (Drone) photogrammetry were integrated to create a complete data set.

1. Data Collection Inventory

| Device / Software | Purpose of Use | Accuracy | |-------------------|----------------|----------| | Leica RTC360 | Indoor and Outdoor Terrestrial Scanning (230 stations) | ±2mm @ 10m | | DJI Mavic 3E | Roof and Inaccessible Facade Photogrammetry | GSD: 1mm/px | | Leica Cyclone | Point Cloud Registration | ±3mm (Global) | | RealityCapture | Photogrammetric Mesh and Texture Mapping | - |

2. Workflow

1. Site Work (3 Days): Scanning of interior, exterior, and roof sections of the building.
2. Data Processing (4 Days): Cleaning, colorizing, and coordinating (ITRF96) point clouds.
3. Modeling (15 Days): Modeling of original building elements using "in-place family" methods on point cloud base in Revit environment.
4. Drawing Production (5 Days): Automatic extraction and detailing of sections and views from model.

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Technical Analyses and Deliverables

Deformation Analysis (Heatmap)

Plumb deviations in historical masonry walls were analyzed using Cloud-to-Mesh comparison.

| Analysis Zone | Maximum Deviation | Average Deviation | Status | |---------------|-------------------|-------------------|--------| | East Facade | 12 cm (Outward) | 4 cm | Critical (Reinforcement Required) | | Ground Floor Vault | 5 cm (Settlement) | 2 cm | To Be Monitored | | Main Staircase | 1 cm | 0.5 cm | Stable |

HBIM Modeling Details

Since standard BIM libraries are insufficient for historical buildings, project-specific parametric families were produced.

• Window Sills: Parametric models that can be adapted according to on-site dimensions.
• Cast Mosaic Flooring: Modeled according to pattern traces in point cloud.
• Wooden Ceiling: Deflection rates of existing beams were recorded in the model.

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Project Results

Architect's Comment: "The building was so complex that manual surveying would have taken months with a high margin of error. Thanks to the point cloud and orthophotos provided by Eos Proje, we were able to examine every stone of the building from our office and make restoration decisions with confidence. Our survey project passed the Board on the first attempt."

• 60% Time Savings: Site duration reduced from 3 weeks to 3 days compared to traditional measurement.
• 99.9% Accuracy: "Surprise" measurement errors in restoration fabrication eliminated.
• Complete Documentation: Digital twin of the building archived to be passed on to future generations.

For expert support in your historical building documentation and restoration projects, contact us.