Starting out at an architecture firm and being able to use BIM software is a huge benefit. Not to mention drawing in 3D can help you draft quicker but it can also help you catch coordination issues while in the drawing phases rather than during construction. One of the challenges with getting used to drafting with BIM software is thinking of the building as a whole while you draft. This relates to a concept I like to call, “Change and Effect”. This concept heavily relates to the overall concept of cause and effect. If you change something what else does it effect in the building. Let me give you some examples to explain my point.
Example 1:
You are in the Construction Documents phase of the project, and the owner has decided to change some of the program. Some walls need to move and the associated items within the room move or change. Your Project Architect (or Project Manager) explains to you what walls need to move in plan and gives you some redlines on the floor plan to pick up. No problem, right?
Moving some walls around takes just a few minutes and then you are back to progressing the rest of the set forward to meet a fast approaching deadline. But wait, you just did a lot more than just moving walls around. In a BIM software most things are associated with each other and need to be coordinated. After moving some walls around you should ask yourself some questions:
Did you adjust the Reflected Ceiling Plans to match the new wall locations? Is there a new intent with the ceilings because of these modifications?
Did the associated rooms and room tags move with the rooms?
What about my life safety sheets? Were any of those walls rated or associated with travel distances?
Did this change a building or wall section? Were windows shifted on the elevation because of these changes?
Did you coordinate these changes with your engineers that are also working towards completing the drawings?
Did you coordinate with the interior’s person on the job? Floor transitions and materials may need to be modified due to moving some walls.
What about your schedules? Did anything change with the door schedule, finish room schedule, etc.
There are a multitude of questions that could be asked by simply changing a few of the walls around. It is up to you to understand that changes affect other views and sheets in the project, and every project has its own associated questions. Sometimes these changes also call for additional coordination with other consultants/partners working on the project. If you are working on a complex project like a hospital, there may be a whole multitude of questions on just the equipment going within those rooms and their associated clearances.
Example 2:
Changing the window sill heights during Value Engineering Process to reduce costs. No problem! Click on all the windows and change the sill heights for all the windows at once to the new height. Say from 2’-0” above finish floor to 3’-0”, and this example will be nice and you don’t have to change the head of the window. So what else does that effect??
If you go to the exterior elevation, did you check to make should any hatching and/or annotations moved with those window sills? While looking at the exterior elevation you notice there is a section cutting through some of the windows. You need to check through all the sections with those windows and adjust the wall details and annotations associated with the sills. For most projects you will have a call out detail or section detail around the sills, headers, and jambs of a window. IF these views are associated with the window those needs to be updated, but if they are ‘drafting views’ in Revit then you do not need to change them. But if when you moved the sill you also changed the sill from a stone detail to a precast sill detail all of that will need to be changed. Done right?
Wait! There are interior elevations showing the windows. Were any of your dimensions effected with this change? Sometimes dimensions get deleted in other views with you make other adjustments. It is unlikely that raising the sill and keeping the header at the same height will effect that much in the interior elevations, but if you make a window larger odds are there will be associated elements that will be effected. (Ceiling, outlets, aligned dimensions, casework/counters, etc) Especially when the documents are complete (When you are value engineering a project after bidding for example) and there are changes that need to be made to the document it changes easily effect a lot more than you originally think.
These examples about the “Change and Effect” concept with BIM are meant to help you think holistically. When you are given redlines or requested to make some changes make sure you are thinking of the other parts of the building that may be effecting. These changes may cause an issue that your Project Manager didn’t think of. By finding this coordination issue and discussing it with your project manager you may learn something new, catch a potential coordination item, or fix a major issue while it’s still early on in the construction process.
It is good practice to check over your work and make sure there are not any major issues by making these changes. Also by using best practices of modeling everything it will help catch any issues. For instance, there should be no reason to draw a line in plan to show a countertop, that is not using BIM properly, it creates more drafting, and increases the likelihood of coordination issues between plans, sections, interior elevations and so on.
Overall, the “change and effect” concept is really about taking the whole building into account when making changes and drafting in BIM. By utilizing the software as it’s meant to be, it will help not only the project progress successfully but also be a great teaching tool for young professional.
Written by Katelyn Rossier