Survey of the Velký Blaník Lookout Tower

We conducted a detailed survey of the observation tower at the summit of Velký Blaník for the municipality of Louňovice pod Blaníkem. The goal was to create accurate and comprehensive documentation of the current condition as a reliable basis for further design work, including complex and hard-to-reach details.

Given the complex nature of the structure, we chose the method of modern 3D laser scanning. This method allowed for the precise capture of the geometry of even the most difficult-to-access parts of the structure. The results were processed and delivered in the S-JTSK coordinate system and the Bpv elevation system.‍

Creating a 3D Model

Data collection was performed using a Trimble X9 terrestrial laser scanner, which enables the acquisition of dense, high-quality point clouds even for more complex structures while ensuring a seamless connection to the control points. Existing control points from the triangulation network were utilized to achieve the required accuracy.

Processing was performed using the specialized software Trimble RealWorks and Autodesk Revit. The point clouds were first georeferenced and then aligned. The object was then vectorized, and the data was prepared for the subsequent creation of documentation. The output is a comprehensive set of data—a 3D point cloud and 2D drawing documentation (floor plans, sections, and elevations) in DWG and PDF formats.

The cleaned data was converted to a suitable format in Autodesk ReCap and then imported into Autodesk Revit using coordinates. The object was then vectorized in Revit, resulting in a 3D model of the building. This was followed by the preparation of construction drawings (floor plans, sections, and elevations) and their export to the required formats.‍

Objectives and Benefits

Our goal was to collect 3D data with the required accuracy and density to create a 3D model with appropriate detail. The main benefit of the project is the high-precision digital capture of the observation tower’s current condition and the creation of documentation that will significantly simplify further design work, technical condition inspections, and the archiving of the structure in digital form.

The creation of a complete 3D model based on laser data enables a permanent record of the structure’s condition, an attractive presentation, and spatial analysis for future planning or reconstruction.

Graphic Benefits

• determining the detailed characteristics and overall geometry of the structure,
• high-precision surveying of the structure,
• rapid delivery of results when needed,
• detailed survey data,
• better orientation and visualization for the client when addressing project changes,
• presentation visualization of the object as a whole,
• suitable basis for design and modeling,
• ability to create cross-sections at any location and at the desired level of detail,
• ability to generate 2D drawing documentation.

Non-Graphic Benefits

• reducing the risk of errors caused by incomplete or outdated source data,
• complying with legal obligations and updating missing or outdated documentation,
• the ability to integrate with facility management systems for further use by the investor,
• simple and quick creation of spreadsheets and statistics,
• easy updating of 3D models.