POINT CLOUDS FOR HISTORIC STRUCTURES
Heritage is defined as anything that has historical worth through art or science, such as named monuments, buildings, or landscapes, and can be classified as material or immaterial.
Environmental conditions, structural instability, growing tourism, and other factors are threatening architectural heritage. It is often costly and difficult to carry out restoration or rehabilitation work on architectural heritage. This is due to a number of issues, including a lack of technical documentation and information regarding the state, shape, and composition of the various elements.
For the preservation of historic structures and monuments in the United Kingdom, extensive documentation and planning are required. This is frequently a major difficulty for those in charge and the conservators concerned, especially when time is short and construction work may be constrained.
Point Clouds are ideal for documenting the present situation in a seamless and timely manner. Data may be delivered fast and easily with Point Cloud scanning, permitting subsequent restoration work and seamless documentation.
Because of the speed and low cost of getting laser scans, it is now feasible to generate point-cloud data for any historical project, especially detail-sensitive historic preservation initiatives.
HOW DO CASTRIA USE POINT CLOUDS?
Point clouds are extremely detailed and precise. Several processes, such as cleaning and purging, must be completed before the point clouds can be used.
Nowadays, a high level of automation is possible through the use of 3D scanning and point cloud technologies, which speed up the collecting and subsequent processing of building data. Laser scanners, in particular, give a tremendous amount of three-dimensional data in a short period of time, in the form of millions of points.
The reconstruction of historical buildings has shown some of BIM’s shortcomings, such as the lack of tools for managing complicated and irregular shapes generated by point clouds.
Here at Castria we have developed several internal processes which eliminate these limitations, by identifying the key elements that require a high level of conservation understanding. Without these processes the use of point clouds would be unmanageable & time consuming
HOW WE PROCESS POINT CLOUDS?
Step 1
Laser scanners can generate a point cloud that spatially depicts the visible elements of a historic building’s (interior and external) surfaces. Working with a laser scanner is divided into three major parts. First, a general workplan is devised, and scanning locations are chosen.
The fieldwork, which includes collecting scanning and/or topographic data, is then carried out. Finally, according to the design, the scanner is put at the defined locations to avoid concealed areas or shadows in the point clouds, and data is captured.
Step 2
Data from the previous stage is analysed and structured in this step before being fed into the BIM environment.
A sequence of procedures, such as cleaning and filtering, must be completed before the raw point cloud may be used. Cleaning and filtering are done with point cloud handling software (such as Recap). Because some high-level interpretation of the scene may be necessary, this is typically a user-aided procedure by a member of our conservation team.
Step 3,
Finally the data may be imported and stored in the BIM environment, allowing for precise and efficient modelling of the various architectural components.
As historic buildings or monuments frequently exhibit various deformations caused by the passage of time or structural issues, such as sloping walls, cracks, or missing pieces. The real shape and spaces of the buildings are provided by point clouds, which is critical for generating an accurate representation of each component.
The elements are first divided into regular and irregular surfaces in order to address the appropriate modelling of architectural artefacts. Elements with many features, such as capitals, archivolts, and embellishments, will be assumed to be uneven or organic surfaces and will be depicted in their fundamental form. Columns, walls, windows, and doors, for example, will be assumed to be normal surfaces and will be detailed modelled. Elements that are critical to the overall architecture will be presumed to be regular surfaces as well.
The laser scanner is an appropriate surveying tool for acquiring a dense point cloud of historic buildings. After adequate digital processing, the obtained data can be brought into BIM systems with the aim of documenting the current state in a seamless and timely manner. This process allows the design team to integrate methods of restoration which would have not otherwise been possible.