Gaussian Splatting in Monument Conservation

Digital recording of historic buildings and cultural objects is already a core tool in contemporary monument conservation. Alongside established methods such as terrestrial laser scanning and photogrammetry, a new technique from computer graphics and AI-assisted 3D reconstruction is gaining traction: Gaussian Splatting. This method can produce very detailed, visually convincing and computationally efficient digital models of real-world objects. What follows is a concise explanation of what Gaussian Splatting is and what concrete potential it offers for heritage conservation.

What is Gaussian Splatting?

Gaussian Splatting represents a scene not primarily as a polygon mesh or a dense point cloud, but as a collection of many 3D Gaussian distributions — so-called “splats.” Each splat describes a small volumetric element with attributes such as position, anisotropic shape (covariance), color, size and opacity; some implementations also store view-dependent properties or normals. When many splats overlap, they form continuous, finely detailed surfaces with natural light interactions. The representation can be adaptive: splats in areas of high detail or at changing viewpoints can be dynamically refined (splitting), producing an efficient, self-optimizing model that concentrates computational effort where it matters most.

Key advantages for conservation practice

- High level of detail: Fine surface features — ornamentation, cracks, flaking, patina and reliefs — can be represented with great visual fidelity.  

- Speed and workflow efficiency: With an appropriate pipeline, capture and model generation can be faster than some traditional photogrammetry workflows because the representation can require fewer intermediate meshing steps.  

- Low-cost capture options: In many cases, a consumer-grade camera (DSLR or smartphone) together with modern GPU hardware is sufficient; Gaussian Splatting pipelines can also ingest LiDAR or structured-light data to improve geometry and scale.  

- Contactless and flexible: As with photogrammetry, capture is non-invasive — physical contact or markers are not required — and light, portable setups allow recording difficult-to-access parts of structures.  

- Compact and scalable data: High visual quality can often be achieved with smaller file sizes than ultra-high-resolution meshes or dense point clouds, while still enabling level-of-detail rendering.  

- Integration potential: Existing photogrammetry and laser-scan data can be incorporated into splat-based workflows, leveraging previous survey investments.

Limitations and practical considerations

- Computational demand: Model creation and interactive rendering currently benefit strongly from powerful GPUs. Post-processing and refinement can be compute-intensive.  

- Metric accuracy and calibration: For conservation documentation that requires millimeter-accurate geometry, careful calibration and scale control (e.g., ground control points or LiDAR integration) remain necessary. Gaussian Splatting excels at visual fidelity; rigorous geometric accuracy depends on input data and workflow.  

- Occlusions and coverage: As with all optical methods, occluded or poorly imaged areas remain challenging and may require complementary capture methods.  

- Workflow maturity: Tools, standards and long-term archival practices for splat-based data are still developing compared to mature photogrammetry and scanning ecosystems.

Application fields and future prospects

Gaussian Splatting is an emerging but promising tool for monument conservation. Practical and near-term application areas include:

- Conservation and condition documentation: High-resolution 3D captures for analyzing damage, material decay and structural alterations.  

- Monitoring and change detection: Repeated captures allow sensitive comparison and trend analysis over time.  

- Measurement and analysis: Dense visual models support dimensional measurements, cross-sections and detailed inspections in the office.  

- Visualization and dissemination: Photorealistic models are well suited for VR/AR presentations, educational materials and public outreach.  

- Integration with HBIM and workflows: With advances in semantic annotation and automated segmentation, splat representations could be linked to BIM/HBIM workflows (e.g., IFC) to provide visually rich, metadata-enhanced models for planning, conservation records and interdisciplinary collaboration.

As hardware continues to improve and software tools become better integrated, Gaussian Splatting is likely to become a more common method in the conservation toolkit. Its combination of visual realism, flexible capture options and efficient, adaptive representation makes it attractive for documentation, research and public engagement. To realize its full potential, the field will need development in standardized workflows, accuracy validation, metadata/provenance practices and interoperability with existing conservation standards and archival formats. With that progress, Gaussian Splatting could become a standard complement — and in some cases a preferred alternative — to conventional photogrammetry and laser scanning for many monument conservation tasks.

Solar modules on listed roofs: Changes to the Bavarian Monument Protection Act 2023

The Bavarian State Parliament passed the amendments to the Bavarian Monument Protection Act (Bayerisches Denkmalschutzgesetz) on 14 June 2023. 

The law brings important changes for monument conservation in 20 articles, including the possibility of easier integration of renewable energies (solar panels) in the scheduled environment - in line with professional standards and a sense of responsibility. 

According to the website of the Bavarian State Ministry of Science and Art (Bayerisches Staatsministerium für Wissenschaft und Kunst), the law aims to "protect monuments, utilise energy potential and support municipalities". The new amendments to the law took effect on 01 July 2023.

The full text of the law and its amendments can be found at the following link (in German): https://www.verkuendung-bayern.de/gvbl/2023-251/

The main regulations for renewable energy installations in scheduled buildings are defined as follows:

1. Priority of own energy needs: permission under monument law may only be refused if overriding principles of monument protection speak against it. The installations should primarily cover the energy needs of the monument or contribute to its energetic improvement. Excess energy input shall be limited in order to preserve the historic appearance.

2. Installation of the systems and preservation of the scheduled building: the substance of the scheduled building should be preserved as far as possible, and the solar energy systems must be integrated into the appearance in a way that is compatible with the preservation of the scheduled building.

3. Professional planning of the facilities: Necessary measures for efficient building operation must be determined individually. Qualified specialist planners, such as energy consultants in scheduled buildings, must submit appropriate, verifiable documentation.

4. Suitability testing of systems based on a stage model: In consultation with the Bavarian State Office for the Preservation of Monuments (BLfD = Bayerisches Landesamt für Denkmalpflege), the regular monument compatibility of systems can be developed based on a stage model for various scheduled buildings. The use of individual solutions is preferred in order to avoid standard solutions. Among several options, the one that is most compatible with the scheduled building requirements must be selected.

5. Visibility of areas: In areas that are not visible, the installation of conventional systems is generally permitted, subject to the premise of preserving scheduled substance and in consultation with the specialist authorities.

6. Visibility of areas in the case of individual monuments, ensembles and surroundings: In visible areas of ensembles and individual monuments, PV systems (e.g. solar tiles, solar foils, systems integrated into the roof surface, etc.) and geothermal systems that are compatible with monuments may be approved, provided that the substance and appearance remain protected. The same applies to so-called surroundings cases (changes in monument surroundings , that can affect the existence or appearance of the scheduled monument).

7. Funding opportunities: The additional costs for monument-compatible adaptations of renewable energy systems as well as energetic refurbishments of monuments are eligible for funding.

These regulations are based on Art. 6 Para. 2 Sentence 3 of the Bavarian Monument Protection Act (BayDSchG) in its new version (valid from 1 July 2023).