3D Modeling of Existing Asset Based on Point Clouds (Scan2BIM)

This document aims at describing '3D Modeling of Existing Asset Based on Point Clouds' use case which is implemented as part of BIM-SPEED EU Horizon2020 project, under grant agreement No. 820553, https://www.bim-speed.eu/en using the 3DASH Tool developed by https://www.cartif.es/en/. This use case allows to obtain the As-Built BIM model of the building based on the 3D point cloud obtained on site in the first phase of the renovation process.

The ‘3DASH Tool’ implemented as part of BIM-SPEED project is developed with the need for the objectives set by the BIM-SPEED Project. It helps in:

• • Time reduction in the generation of walls in BIM from point clouds.
  • Accuracy in the generation of walls from point clouds due to the fact it is a mathematical process based on algorithms.

A tool that supports the creation of As-Built models using point clouds as data for the generation of BIM models using REVIT software with these users benefits:

• Time reduction: both to generate As-Built models and to compare with previous existing models, or to generate these models if you do not have previous documentation.
• Accuracy: the tool gives a high accuracy since it is a mathematical process based on algorithms for the detection and generation of walls using point clouds, compared to the manual process that would be for the user to generate the walls using as a template the point clouds, as it would never have the same accuracy in the selection of the points.

The tool needs a manual process by the user to check and edit the types of walls generated in case there is any overlap between them, but even so, this time would be less than the time it would take to manually do the whole process.

• Autodesk Revit Website. Available online: https://www.autodesk.es/products/revit/overview.
• BIM-SPEED (2021) 1: Methods for architectural, structural, thermal 3D data acquisition of existing buildings. BIM-SPEED Consortium, Berlin, Germany. See https://www.bim-speed.eu/en/results (accesed 08/07/2021).
• BIM-SPEED (2021) 2: BIM Connectors for interoperability between different BIM tools and with the BIM-SPEED Platform. BIM-SPEED Consortium, Berlin, Germany. See https://www.bim-speed.eu/en/results (accesed 08/07/2021).
• BIM-SPEED training materials area. Available online: https://www.bim-speed.eu/en/training-materials 

• 3DASH: 3D Modeling Based of Existing Asset based on Point Clouds
• BIM: Building Information Modeling
• GUI: Graphical User Interface
• IFC: Industry Foundation Classes

The overall process for 3DASH Tool is presented in the figure below. The procedure starts with collecting the 3D point clouds by the user acquired by laser scanning or photogrammetry systems. The overall process is further explained through its implementation on two demonstration sites.

As shown in the image above, there are three different parts involved in the process: the user, the BIM‑SPEED platform and the databases:

• The user has to start three different process if it is the user’s first time using the tool:
  1. Obtain Point Clouds: First, the user has to obtain the 3D point clouds and transform them to PLY, PTS or PTX format.
  2. Install 3DASH plug‑in: The user has to launch the 3DASH Tool in the BIM‑SPEED platform to download the 3DASH add in and install the add in in REVIT.
  3. Launch the 3DASH Tool in REVIT.
• BIM-SPEED platform: The BIM-SPEED platform allows to launch different services hosted on it, being able to launch the 3DASH GUI (Graphical User Interface) from the platform following the user’s commands.
• Databases: There are two different databases in the process:
  1. User database: The user can save the data in its local database.
  2. BIM‑SPEED platform database: The user can upload and download data from BIM-SPEED platform.

The details of the implementation of this tool in two demonstration cases are covered in the next section.

DEMONSTRATION SITE – Jazdy Konnej, WARSAW, POLAND

The demonstration site is located in Warsaw, Poland. The building is an underpass. The point clouds upload to the tool in the first step ‘Analyzed’ is shown in the image below:

The second step is the pre-processing process where several parameters are selected, the results of which is shown in the following image:

In the segmentation step, the user can modify different parameters such as the smoothness threshold which indicates the maximum deviation between the normals of the neighboring points. The results for the Warsaw demo is shown below:

The analysis step makes it possible to determine, among other parameters, the maximum distance between a point and the virtual plane to which it belongs. The results for the parameters selected in the Warsaw demo are shown below:

Finally, the user can select the wall type to be applied in all the walls generated by the tool, as shown in the following images:

With the options selected by the user in all the process, 88 walls have been generated and the time spent for the automatic generation was 77 seconds (excluding the time spent by the user in selecting parameters). The final result obtained for the Warsaw demo is show below:

More information about this demonstration can be found in the training area of the BIM-SPEED website https://www.bim-speed.eu/en/training-materials and in the YouTube channel https://youtu.be/pJB1pGj1I34.

DEMONSTRATION SITE – ARCAYA 5, VITORIA, SPAIN

The second demonstration site of the use case 3DASH4Scan2BIM process has been carried out with the Vitoria demo, the building ARCAYA5. This demo is a residential building located in the city of Vitoria-Gasteiz, Spain. The steps are the same as those identified in the previous demonstration, so only the results are shown below:

In this case, the point cloud of the building was only of the main façade, obtaining 14 walls with the 3DASH tool. The time spent for the automatic generation was 18 seconds (excluding the time spent by the user in selecting parameters).