The Drafting Side of Building Information Modelling (BIM)
Table of Contents
The Building Information Modelling (BIM) industry has undergone a recent boom with many exciting new developments. Along with this rapid growth, comes not only opportunities but new challenges. While there are numerous explanations on how to successfully execute projects within the BIM environment, the role of the drafting side in these explanations are often lacking. So, this article will highlight some of these challenges on the drafting side of the BIM industry, how to address them, as well as methods and tips to plan, start and successfully execute projects.
1.1 What is BIM
BIM (Building Information Modeling) is an intelligent 3D to 6D model-based process that gives architecture, engineering, and construction professionals the insight and tools to more efficiently plan, design, construct, and manage buildings and infrastructure.
BIM remains a powerful tool even if you don’t aim to move to the harder to reach all the way to 6D. But, working up to 5D will already assist both your company and clients with a better understanding of how projects are executed and management. Working with BIM is an opportunity for the engineer/contractor to enhance open and transparent communication with the client about their projects.
Let’s first understand the various levels of BIM.
2 2D to 5D Explanation in a Draughting situation
Traditionally, all modelling was done manually in 2D. In fact, despite the incredible advances made in computer and drafting software capabilities, some companies still exclusively use 2D. Of course, some drawings still need to be done in 2D, e.g. process planning, plant layouts, etc.
However, modelling only in 2D does not cut it anymore and to stay relevant any serious design office need to at least upgrade their drafting capabilities to 3D.
2.2 3D – Sized Components
At this step, you start incorporating the intelligent modelling side of BIM. Here you have the opportunity to stop using extrusions as model placeholders but use actual sized and shaped components. This means structural beams, piping etc. will have accurate sizes, weights, and specifications from your most often used design codes.
From these models, you will be able to extract full Bill of Materials/ Bill of Quantity/ Material Take-off/ Material Take outs for these components.
If you utilize your programs correctly, you can create 2D design drawing from your 3D models, while they are linked to each other. So, updating the 3D models automatically update your 2D drawings.
2.3 4D – Project Schedule
Here things get interesting and fun. 4D BIM Modelling incorporates the project schedule.
After all the hard work has been done to setup the 3D modelling, Project Planners need to change the schedule multiple times to suit all the subsequent changes made to the 3D model.
With 4D BIM Modelling, you combine that 3D model with the Schedule in one programme. Now you will be able to simulate your construction projects to accurately predict if your schedule works smoothly or if the changes result in any clashes.
During execution, as the schedule is updated the drafting office can keep verifying the 3D model still correlates to the updated schedule.
2.4 5D – Project Cost
5D BIM modelling, takes 4D and adds Project Cost.
When you have successfully integrated your 3D model and 4D Schedule, you can start adding your costs, taking your model up to 5D level. This means you will be able to immediately determine how much any clash/ delay/ change will cost and the impact on the overall capex of the project.
This allows for quick, efficient, modern decision-making tools to deal with any proposed changes. The full scale and impact of any changes can be modelled before large amounts of money and time is spent.
Small CMS Station 5D Screenshot – showing a model integrated with cost and schedule
2.5 BIM from Drafting Perspective
There are various explanations of BIM, but none of them talk directly to the Drawing office side of this technology, only the theory. Most people, therefore, fail to understand the entire concept, resulting in mistakes. If the drawing programs are not setup correctly they won’t be used to their full capacity. This is the main reason why most people give up after developing BIM systems.
There might be BIM specialists out there that know the theory of the systems, but so many forget the information they will use in the 3D model when they start moving into 4D and 5D. Yes, the drawing office is just as important to this system as the technology and theory.
The specific drawing programme, or technology, does not matter so much. There are various, and they are all good with their own pros and cons. The concept stays the same, all the way to level 5D.
Design Drafting Staff have a streamlined way of designing and modelling, and this will have to be adjusted slightly to ensure that the models that are being produced will fit to the construction/fabrication schedule to ensure seamless integration in your Secondary programme. But having the knowledge to design, you have the thought process to make quick and intelligent decisions.
Completed Intelligent 3D Model (Navisworks)
3 Advantages of using BIM Systems
3.1 Project Construction Planning
You can use this tool to simulate the construction sequence. You can break it up into sections (Days/hours), so in the morning’s site toolbox meetings you can show your teams on which areas they will be working on. In this way, you can track on one program the Actual Start and End Date.
3.2 In-house Training
Setting up a model to use in the office can give your employees or fellow draughtsperson a visual idea what you are trying to teach them. They can keep that file (we use Navisworks Manage) so they can measure and refer to those files. They will be able to see the correct specs and safety distances.
3.3 Client liaison at progress meetings and interactions
Creating an environment where the client can have real input into their own Infrastructure, (in our case Plants/Tank farms etc.) will enable you to deliver a better end product. This minimizes changes later in the project when most of the work has already been done.
3.4 Cost prediction in real time
When you run the simulations and construction has started you will be able to track the costs and actual timelines in one place, with models and updated information. Changing the actual time started will indicate a change in the cost which you can see immediately.
3.5 On-site personnel training on Equipment/Operations
When you have a large plant and it can get noisy in there, it is very difficult to train an operator in those conditions. Using the BIM tools, you can sit in an air-conditioned office and show them exactly where and when they have to be there and spare your time and also reduces the risk for someone to not understand. It’s also safer.
3.6 Fabrication/Construction can be done from the model
Using the 3D model in a program such as Navisworks will enable you to use that as a fabrication method. Using visuals instead of other drawings which can be confusing to some can save time and predict problems beforehand. This is a big step forward and the benefits will be great if you can ensure that your designs are sound.
There is quite a lot of preparation to be done to ensure that your company can execute a BIM project. If you realize in the middle that you are not prepared it will be much harder to fix the projects and the delays will be immense.
4.1 Method Statement
It is important that you sit with your dedicated BIM team and create a Method statement of how you will execute your projects. Ensure that your team has the same idea and are aligned with the end results. There are a lot of examples on how to do this, but do not over complicate it. When you over complicate it, the chances that your team will not understand the process and mistakes will be made.
4.2 Design Criteria
After you have written a Method statement, you will move to a design criteria. This document will assist the Drafting Staff to know the standard they should be drawing to. This will include 100% correct layer naming, document numbering, details that need to be drawn in, amount of model break-ups etc.
Training is one of the most important steps in the process. Training your employees on what to expect and what is expected from them in this journey is important. You will ask of them to work to high quality and concentration to ensure their models are correct for the use of BIM. Letting them understand the entire purpose of BIM and the excitement about it will give everyone a common goal.
It will not be necessary to send everyone on training for 2 days, but maybe send a few leaders and let them guide and teach the rest of the team. The drawing teams will have to be educated to understand construction sequences because they have to draw the 3D models to communicate the idea to fit the schedules.
4.4 Start Small
Start with a smaller project. Have a DEDICATED team that executes a smallish project so all the lessons and gaps can be filtered out. On the smaller jobs, it is easier to fix a mistake and catch up, larger project gets confusing an overwhelming to everybody. Especially when the whole team is still learning and finding their feet. Remember that the timelines on these projects differ to those normal 3D modelling projects because of the attention to smaller details should now be taken into consideration.
After creating those two crucial documents (Method Statement and Design Criteria) you are now ready to setup your projects (referring to the Drawing office environment). This might be different than what you would have done other projects. Take a look at how you will split up your drawings and how you will be drawing them.
Model for Two Pipelines across a Bridge
Knowing there will be pitfalls and how to avoid them is a crucial part of executing a BIM project successfully, and there are a few if you are not ready or not setup for the time to come.
The project managers need to be updated on how long these types of projects take. This you will learn if you do that smaller project to test the waters. It is much harder to keep track if the time limit is TOO short and it is a large amount of data and it is a new area of expertise.
5.2 Correct Modelling
It is of utmost importance that the team adhere to the Method Statement and the Design criteria. When the correct layer numbering and naming is not used, the BIM software will be confusing and finding items to connect to your simulations will be difficult to find in a model with so many components.
Do extra research to be sure that you understand the concept correct. Because there are so many varieties of this process, it can be up to you to take a piece of each to puzzle and complete it.
5.4 Discipline interactions
Part of the purpose of BIM is to start creating a more combined working environment for all disciplines. This will stop the battles between each other. Understanding each other’s role for the end goal can improve the productivity. At this stage, the integration is important between the project Scheduler and the draughtsperson so that they can start drawing the correct information to suit the schedule.
5.5 Quality Control
Be sure to make provision to quality check your teams work regularly, once again you do not want to realise at the end that something is not up to standard. Be sure that they stick to the design criteria and double check that the model correlates to the project schedule that has been setup. In a perfect world the schedule should be done before the modelling starts, but we all know it is not a perfect world…
5.6 Software/Processing speed
Using up to date software and computers assist in the process. It can be demotivating to the team to have constant slowness of computers and also slows down the entire process.
Quality assurance example – project set-up in drafting environment
6 Incorporating PointCloud Data
Incorporating PointCloud data into your BIM is one of the best tools for the Brownfields and even Greenfields sites. An intelligent 3D model can be created from Brownfields As-built Lidar Scans. Scanning is such a great tool to assist in clash detections and minimize the risks thereof also assisting with fabrication.
In Greenfields areas, the point cloud can be used for space planning and future expansion planning. Important to know about this tool is that it can be misunderstood and then be misused. Having the knowledge to use it can improve your productivity as well as a better end deliverable.
The quality of a scan is the first key point in seeing the value of the PointCloud data. It is a bit more expensive to use but the value it brings is priceless.
Creating a rule of thumb for the scanning teams to know how many times around equipment they should be scanning to create the best resolution for modelling is important. Having experience in scans that were not up to standard and struggled through modelling with it and losing faith in this technology (my first scanning project), it is difficult to maintain a high standard of modelling.
Next is to determine a length of time the scanner should scan at one position also improves the quality of the scan. The longer, the better.
The file sizes of these scan can be enormous, so determine if you can use the black and white version or if you need the scan colour version. It seems to assist if it is in colour because the teams can have a better idea of the site since not the entire team can go to site.
After the scanning has been done, the correct processing of the scans need to be done. This needs to be someone that understands the environment and knows what to look out for when there are problems. The problems might be anything from a few misalignments to the orientation is wrong.
It is crucial that enough time is giving for the scans to be completed and processed. If this is not done, you have scans that are unclear or the scan misaligns and inaccurate work will be done. If improper scans are done then more money will be spent to send people to site to do manual markups again (more inaccurate) or send the scanner again (costly).
6.4 Training, Training, Training
No one can be good at anything if they are not trained or at least assisted into the correct direction. Using the PointClouds are a real challenge (take it from me) and training needs to be done. There are intricate ways of dealing with a PointCloud. Knowing how to use the PointCloud, the most complex structure/equipment can be modelled from it. Do not lose faith in the technology, if you feel that you are not satisfied with its performance, it might be a flaw in the process. Remember that with correct processes in place, and correct scanning, it is a tool to improve productivity and time, not decrease it.
The data from PointCloud scans can vary from 40GB, 600GB, 1TB or even larger. These are massive amounts of data. The PointCloud data is sensitive and it references a lot of different files. There are ways to ensure those reference files become one.
To store this type of information, you will either need a massive server just for PointCloud data or you will have to use those combined data sources and add only the piece of puzzle that the person is working on, on their computer. Breaking the PointClouds up into respectable areas seem to work better than everyone working of off one set.
6.6 Software/Processing speed
The same principal counts for working with PointCloud Data in your software than with the Modelling if not more so. The PointCloud uses a lot of processing power to run so computers that can run this should be strong. With that said, making a PointCloud more user friendly comes with the training thereof. Be smart, work smart.
End Result with Quality assurance. Now you can start 4D connections and 5D incorporation.
Working with Autodesk products have been accommodating with the PointCloud and BIM environment. They have programs that are just viewers and many designing programs for all disciplines which work well with Navisworks (also Autodesk). The files import seamlessly into each other.
The entire BIM process, including the various technologies can be intimidating, but with proper research, preparation and some of the discussed tips, it is possible to achieve huge project success using BIM.
Don’t forget about the worker ants (draught personnel), they have to build the nest and they know the flaws and challenges behind the theoretical methodologies. Keep your entire team updated and in the loop during the entire project and ensure their opinions and concerns are collected and incorporated. Without the worker ants, there will be no nests.
Remember that the BIM environment is made for people to come together and create a more integrated environment.
Author: Christelle Bosch, Drawing Office Manager and Draughtsperson at EPCM Holdings (Connect with her on LinkedIn)
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