Fellow Engineers, Modelers, Bentley Operators, etc.
Last year in July 2017 at the 9th International Visualization In Transportation Symposium I presented an abstract detailed an alternative approach to working with Corridor/template design.
This approach is called "3D Linear Method". It is the complete opposite on what Bentley encourages in their teaching workshops, and consequently the opposite what is demonstrated by every major Department of Transport I have encountered. A brief outline on how it works:
Instead of single templates/corridors spanning the whole width of each roadway alignment, the corridors are broken up by element. 1 corridor per curb, lane, shoulder, guard rail, end condition, wall, barrier, etc. Each piece is connected to each other, eventually connecting directly or indirectly to control lines.
While this creates 100's of extra corridors, the advantages make this technique far superior to the designer, and end user (client of contractor) than the current approach for the following reasons:
1) Templates are simple, easy to create, and have no complex display rules so they are functional for the novice user
2) The same template can be re-used 1000's of times, across any project, making the data consistent 100% of the time, giving reliable consistent symbology when the data is visualized
3) The consistent nature of common templates used always simpler digital quantities to be extracted, as similar objects can be collected by symbology
4) Changes are more manageable - change only the parts you need to change, and the connectivity of all the other corridors will automatically be adjusted
5) More than 1 user can work on the same road in the same section at the same time as everything is broken into smaller pieces
6) Simpler to train - for those unfamiliar with a 3D environment, this 3D Linear Method is identical to criteria
7) Processing is substantially reduced - it is quicker to process 100's of small corridors with no complex rules than 1 or 2 massive corridors with lots of display rules by a factor of 10.
This technique has been implemented across every designer I have worked directly with in Illinois over the past 4 years, and there has been 3 distinct reactions:
a) Those with some 3D knowledge embraced it fully, recognizing that this is the ONLY way to utilize the software, no exceptions
b) Those with minimal or zero 3D knowledge dismissed it entirely, citing "This is not the way Bentley teaches it"
c) Those with medium experience recognize its power, and use a toned down version of 3D Linear method - they build templates that span all lanes, 1 for shoulders, then 1 for end conditions, for example.
Overall it has been received positively from those who understand the software's limitations, and widely used across Illinois Tollway I-294 project currently underway.
This modeling technique has caused quite a controversy here from the State Government in Illinois (IDOT) due to the radically different approach. So I wanted to hear from the greater community regarding this technique.
If you would like to contact me directly about this, feel free to do so:
Alexander Badaoui, PE: P 312.467.0123 | abadaoui@terraengineering.com
The presentation I made showing this in more detail is found here:
https://www.youtube.com/watch?v=Se8oQvVNw_w&feature=youtu.be
The attached PDF is a summary of the abstract presented.
https://www.dropbox.com/s/7jwku3ns2cu7aql/Abstract%20-%20Developing%20Visualization%20Transportation%20Models%20-%203D%20Linear%20method.pdf?dl=0
This was geared towards a non-technical audience. The following power point below is more technically driven, detailing how the naming convention operates in Illinois:
https://www.dropbox.com/s/dxq9nrm5z5vc63i/2018-03_AB%20to%20IBUG_May%202018%20-%20Part%201.pptx?dl=0
Thanks in advance for your feedback on this technique.
I met Alex about a year and a half ago and took his class on 3D Linear Modeling for a job that we were a sub-consultant for. The first thing I noticed about Alex is simply how fast he can create a model. He could take a complex job and turn around a full model in just a few days. I was fortunate enough get personal training directly from Alex on his 3D linear Method for that particular job. I simply cannot thank you enough Alex for sharing your knowledge and the countless hours you must have spent to perfect your technique - and I do realize it is constantly evolving.
I since have worked on jobs using full Bentley style templates and Alex's "3D Linear Method". For clients that require modeling the "Bentley taught" way I do stick with that method since we are required to. However, when given the opportunity to model the way I want to, I have found using Alex's method always provides a more logical model that works better. I do like using the Bentley way as well, but this works best for simple roads. If there is any bit of complexity, there is no doubt I'd use Alex's method 100%.
Here are the strengths that I found using Alex's method:
1) It is much easier for people to learn and understand the 3D Linear Method than using full templates. 3D modeling has always stressed me out because there are very few people that can actually do it. I would end up being the only one in the office that could model with the full burden being on me to finish it. With 3D linear modeling I was able to teach multiple people how to use Alex's technique very quickly. Now we have multiple people working on different sections at one time. It's a method that is very intuitive so people seem to pick it up very quickly.
2) I would say most users "throw in the towel" mainly due to the complexity of the full templates that Bentley teaches us to use. Alex's 3D Linear method breaks these full templates down so we can more easily focus on a component and what it needs to do. Since these components are in their own corridors, there are far less point controls, parametric constraints, etc. in the given corridor which makes it easier to understand - and that leads to faster modeling.
3) The whole "extremely daunting" process of making full templates is removed. You can simply just start modeling if you have components already made.
4) Since components are used over many corridors, those corridors will all be updated correctly by changing the single component. The same cannot be said if you used a full template. For instance, using full templates - if the roadway surface changes thickness, you would have to go to each template for the entire job and make the same change in each template, or maybe you could go to each corridor and change a parametric constraint. Using Alex's method you can go simply open the lane component and make the change, then sync templates on your corridors.
5) Multiple users can pick up where others left off on a given corridor. Due to the ease of the corridors with less controls, it is easier to open a file that someone else created and modify it (if need be). This has always been a problem with full templates due to all of the controls within them.
6) Earthwork methods are greatly improved. For the job I am working on, we are required to show earthwork quantities at all stages of construction. Alex's method allows for this much better than full templates. For instance, the way I used Alex's method is to first model the final conditions. To model each stage, I can use corridors that were already created from my final conditions. For instance, if I were building a 4 lane highway, and lane 2 was being built in stage 1, I can create a new dgn file and copy in the lane 2 corridor into my new dgn as a starting point. If I were using full templates, I'd have to start from scratch for each stage. On a side note, I can also separate earthwork numbers if need be since I can calculate earthwork by corridor. If I were using a full template I would not have this ability.
7) I don't think Alex mentioned this above, but he teaches to run all pavement corridors on a point control to a main pavement construction corridor. We essentially create a "construction" corridor (the main pavement corridor) that is attached to the superelevation corridor. This corridor is the top of pavement at its simplest form and has no depth. It will have all of the main lanes at their correct widths that will follow the superelevation. When we create our pavement corridors (the true model) we will point control the inside and outside of each lane to our construction corridor. By doing this we have just simplified the entire backbone of the job to be controlled in a single corridor. If there is a superelevation change, alignment change, profile change, etc. you simply go to the construction corridor and make the change and your entire model will follow it. On our current job we had both an alignment and profile change. This came in very handy.
The one negative to using Alex's technique is house keeping. Since there are so many corridors, it is very important to come up with a naming convention for those corridors or you will loose track of them very quickly. You get used to this once you start doing it though. When you have to start pointing to those corridors to get information, you will pat yourself on the back if you named them using a system. For instance, when completing end areas earthwork, if you used a naming system you can easily select just the corridors you want to get earthwork numbers from. The same goes for cutting cross sections.
I hope this helps someone - so sorry for the long read!
Dennis
Thanks Dennis for the detailed summary!