Mar 16, 2015 -- It is interesting how point cloud models of various buildings, sections of buildings and landscapes can be easily obtained by using sophisticated laser scanners. However, these point clouds cannot be used right away for Revit family creation or BIM. Expert intervention is always required in order to convert these point cloud models into surface models that can be used for BIM.
3D Laser scanners are used to measure millions of points across a building and to capture all the details, dimensions and demarcations. These point cloud models are given to 3D modelers as input data in order to develop building information models. So what is the role of a 3D modeler here?
Just trace over a Point Cloud – And you have BIM! – Sounds easy!!
A lot is talked about scan to BIM, where the common perception seems to be that, the point cloud data is traced upon and TADA!!! A BIM ready model is there. However working with point cloud is much more than just tracing over existing models, and only a modeler or a BIM expert can tell you that.
This reminds me of a project I was working on, where our team received nearly 300+ scans in .pcg format. These scans included the architectural and structural details of every section of the building. Our team developed 3D models of the ‘as built’ structure with 10mmaccuracy and LOD 300 as requested by the client.
Working with Point Cloud and Scan to BIM challenges!!
Now, Point clouds can be highly complex, and working with these, requires experience and deft handling. However, the biggest challenge in our project was that the scanned data provided to us by the client, had several missing sections and a lot of inconsistencies. This will happen most of the times, and it depends on the acumen of BIM experts and engineers how they handle these inconsistencies.
Our engineers studied the point clouds and identified errors and missing parts. As the data volume of Point Cloud was high we had to divide the data into subsections and this required a lot of management and collaboration between the team. The missing data also had to be constructed using engineering assumptions; this was done with the help of existing scanned data and reference images provided by the client.
Now like I said, converting point cloud to BIM is not just about tracing over the model, it demands a lot of complex modeling. Moreover, BIM experts working on such international projects do not have all time at their disposal. The deadlines are insanely tight.
Successful Project Management and Delivery
In addition to BIM capabilities, communication is also one of the prime aspects that leads to successful management and execution of a project. From our end, we always communicate every aspect of the design thoroughly withto the client.
Ultimately after all the work, rework, communication, scanned data management and modeling activities that we carried out, an Information rich, intelligent BIM was ready. Our clients used this model to schedule, plan and coordinate the renovation work. Eventually, they managed to save around 20% costs on renovation as they had such flawless documentation available.
Our team has also worked on Scan to BIM projects where in addition to scanned data for some section of the building, 360 degree image views were also missing. In such cases waiting for the inputs from client’s side often results in delays so we prefer working based on our engineering assumptions and later alter the models when we receive the remaining input files. Often the engineering assumptions are so accurate that there are hardly any changes to be done after we receive the actual images and inputs.
Our choice of software: We use tools like Revit and Navisworks, unless specified otherwise by our clients. Revit is building design software, which includes features for architectural structural and MEP disciplines, thus allows development of an intelligent BIM. With Navisworks, professionals can review the integrated data and models, and exactly like the software claims, it helps coordinate and plan projects, resolve conflicts and gain control over the project outcomes.
About Author: Nikunj Patel is a design engineer working with Hitech CADD Services for the past 4 years. He loves designing specialized industrial equipments and can always be found in the lab discussing, brainstorming & tweaking designs. He has also worked on architectural projects taking interest in every aspect of design & analysis.