Revit Arch to GBS

[jstrapko]

Thanks to AUGI for starting this forum. I am attempting to use Revit and GBS as part of an architectural design course. New to both Revit and GBS, I have found the best approach for me to get results is to start with a simple one-room model without openings or interior partitions and export to GBS. After successfully adding detail and getting results, I am trying to understand and control default settings for envelope components. I have made progress on the understanding, but not on control. Any observations would be helpful. A record of my progress can be found at Jim Strapko GreenNotes, http://jastrapko.wordpress.com
The attached screen shot shows GBS defaults added to my generic model. I would like to know how the R13.3 8 inch concrete wall was selected by GBS and if such defaults can be controlled by a user.

[Mike Sealander]

If I had to guess, I'd say GBS is using an insulated concrete wall assembly with a minimum r-value to meet either ASHRAE 90.1 or another standard. 8 inches of concrete is a far cry from r-13, although some texts say concrete has an r-value of 2 or so per inch.
GBS basically lets you choose from three or four typical constructions for roof, window, wall assemblies. You can change each construction and see how it affects your model. You can't change the r-value of a wall from 13 to 14, or any other random increment. Pretty much you have to choose from the options GBS presents.
The idea seems to be to give designers very broad-brush options on their designs. Further tweaking would have to be done in Energy Plus, using the EnergyPlus output file that GBS offers.

[jstrapko]

Mike, your insights are helpful. The broad- brush approach, allowed me to generate a half-dozen design alternatives in around twenty minutes. Still, it would seem logical to have some control over base run defaults.
My next step will be to run eQUEST on the same model. If time permits, I may try Energy Plus as well. Thanks for mentioning it.

[jeffh]

Once you create a project in GBS you can modify the defaults that will be used for the construction, use, etc... You can also save these changes as a template in your GBS account, then the changes can be quickly applied to other/future projects. Attached are a couple of screen shots showing where these changes can be made.

[tomislav.zigo]

As Jeff has pointed out you can use the template to define your wall assemblies. The one problem that I have encountered is that GBS's list of wall assemblies is somewhat limited and the way to define your own assembly as the default one is not available. One workaround is to define the construction tag within the gbxml file after it was generated by Revit and push that as your default material for analysis.

TZ
http://bimology.blogspot.com

[jstrapko]

jeffh, Your attachment got me on track. I find the screens for defining templates a little confusing, but have managed to define several alternative templates. Apparently, I can assign only one space type to each template. If I understand this, it means the entire building will be analyzed as though it were a single space type, "OfficeEnclosed" for example.
Thanks, Jim Strapko

[jstrapko]

Trying to run GBS analysis using the new templates initially returned error messages. After starting a new project errors were eliminated. Creating a series of templates, changing space types and adding surfaces one-at-a-time returned successful results. I think errors resulted from my mistakes defining surfaces. Once I got past my own errors, results were returned by GBS quickly.
Thanks,
Jim Strapko

[Mike Sealander]

Jim:
I've been looking at eQuest and EnergyPlus. eQuest is by far the more user-friendly. Also, the output from GBS to EnergyPlus is for the version 2 program. Version 3.0, released this fall, has significant definition changes, and from what I can see the GBS output doesn't agree with 3.0.

[jstrapko]

Mike,
Thanks for the warning. I have had to set aside work on eQUEST temporarily and may simply read about Energy Plus. The web is chock full of interesting software tools and I have time to sample only a few.
Jim Strapko

[jstrapko]

Students in my GBS design class are trying to run a 16,000 square foot fire station that includes vehicle bays, office, dorm, and meeting spaces. Some rooms are on a mezzanine level. Part of the building is angled. There are two different roof heights. It is not a simple geometry. Error messages indicate that GBS is not seeing floor, walls, or ceiling.
They have done everything I can think of including redefining room perimeters, checking volume calcs are on, verifying room offsets properly intersect roof, etc. Still, error messages indicate no roof, walls, floor. Stripping out all interior walls and defining the building as a single room does not help. Stripping out footing and foundation does not help. What is left is a relatively simple box that still returns the error messages.
Now they will take my generic fire station, which does run properly, and try editing its geometry to match the actual fire station. They will try to run GBS at steps along the way. I will post results here and ask them to join this forum. I trust we can find help here.
Jim Strapko

[jeffh]

Sometimes the "no roof" error message form GBS is a bit of a red herring. The issue may be realted to some other area of the model completly. It is hard to say exactly what the issue might be. Remember GBS works better the earlier in the process it is used. going back to a "working" model and making changes one step at a time and running it through GBS is probably a good troubleshooting method.

[jstrapko]

Today my students led by intrepid Nick Schorr overcame all obstacles and successfully ran GBS on a modified version of my generic fire station.
Jim Strapko

[davido.204584]

Today my students led by intrepid Nick Schorr overcame all obstacles and successfully ran GBS on a modified version of my generic fire station.
Jim Strapko

It appears that I am having a similar issue to your students and I was wondering if you could share how they overcame it?

[tomislav.zigo]

Today my students led by intrepid Nick Schorr overcame all obstacles and successfully ran GBS on a modified version of my generic fire station.
Jim Strapko

Considering the existence of different use types, variable plug loads, and materials within the model, I would like to know how those issues were being addressed.
Also would you be willing to share gbXML files and comparative results from the design optimization runs?

Thanks

Tomislav

[kyle.bernhardt]

Today my students led by intrepid Nick Schorr overcame all obstacles and successfully ran GBS on a modified version of my generic fire station.
Jim Strapko

Glad to hear things worked out in the end. What ended up being the issues that were found?

Cheers,
Kyle B

[jstrapko]

Students eventually abandoned the original rvt file that failed to export. They started again with a generic fire station I drew. I ran this model repeatedly through GBS, progressing from a simple box to a more complex geometry with doors, windows and interior partitions. They modified my model to match the irregular footprint of the existing fire station we are renovating. They added mezzanine areas not included in my model. They exported to GBS and produced baseline and alternative reports. Nick's envelope input to GBS was guided by Graham Ryan's COMcheck values. In short we overcame problems by starting a new model, developing and testing it step-by-step.

My process is summarized at http://jastrapko.wordpress.com
I have asked Nick Schorr to review and respond to above questions on this forum.

Next: after we have designed the addition and renovation, we will run GBS and probably eQUEST as well.

Either Nick or I will upload any files you want to this forum -- as soon as I can figure out how to do that.
Jim Strapko

[jstrapko]

After purging, my generic rvt file uploaded. I think the inp file extension prevented the transfer file for eQUEST from uploading. if anyone is interested I can email it or maybe temporarily change the extension.
Jim Strapko

[kyle.bernhardt]

Thanks Jim for posting, should be a good item to have for others interested in the topic. Is there anything specific you wanted us to take a look at for you?

Cheers,
Kyle B

[jstrapko]

There is no need to look at anything in the generic file uploaded. It ran in GBS successfully.

[Teresa.Martin]

Hi. I actually also teach and developed course ware for Revit, GBS and 3D Max Design (Lighting Analysis Tool). In regards to the issues with the model, a couple of things...
1) Walls, floors and roofs need to be joined.
2) Cut sections through your mezzanine levels, turn on the room objects so you can see them in section, and drag the room so it reaches to ceiling/floor above. I am wondering if this was part of the problem.
3) GBS supports curved walls and it supports sloped (non vertical) walls, but not both at the same time.
4) Objects such as sunshades, exterior shading devices, etc. cannot be generic model families, they must be a floor, roof or wall type typically in order for GBS to know what it is.
5) Revit MEP has spaces/zones that let you define whether or not a space is occupied and therefor gives you better calcs then Revit Architecture, at least initially.

I hope you find this useful.

Best regards,

[jstrapko]

Teresa,
Thanks for the overview. There is some curved curtainwall, but nothing more complicated in our fire station model. We are completing schematic design based on initial Revit-Arch-GBS runs. When the model is ready (next week I hope), we will try running Revit-Arch-GBS and Revit-MEP-GBS. We may be asking for your comments and those of others here -- all have been valuable.
Jim Strapko
http://jastrapko.wordpress.com

[schnica]

This is Nick Schorr, the student working on the Green Building Studio issue for the fire station. To summarize what I have done is as follows.

1. I did re-draw the entire fire station from ground up. To include all footings, foundations, different wall types, new doors, new windows, and a flat roof. Ran the GBS software along the way checking it every other time I changed something.

2. Checked to make sure all of the walls are connected, and roof is attached.

3. Adjusted the "room volume" to the top of the roof

4. Ok, now I had a basic rectangle Fire Station. Unfortunately, our fire station has a 30 degree angle addition. So I added this addition and had an issue with the walls joining. Eventually I drew another wall on top of just that 30 degree intersection and that worked.

5. Our drawing has different floor elevations. (ie one of our bays in 4" lower than the floor next to it.) I moved that floor, actually just re-drew that section and moved the floor down 4 inches. This caused another issue that I could not resolve until I moved the floor back up to original position.

Now I had a "basic" model. I was still using "generic" wall definitions. I was just trying to get a basic run. To this day, I still have not changed the walls to their full definition (ie brick veneer over 12" CMU)

7. Next I started adjusting the R level of insulation, Roof insulation, Heating and Cooling Points, Window U-factor and Door factors. This was all being done from the GBS website in the design options section of my project. The only issues I ran into were with doors. There are two selections for the type of door you have. The one that has a U factor DID NOT WORK. The generic door definition one did. When using the U factor door as an option, the GBS software would stop in the middle of analyzing, and would say it had an error. It took me a little bit of time to trouble shoot that one. So I just left the door generic.

Since this original model, we as a class have changed a few things. We have added a round curtain wall to the front of the building, and made a few more little additions to the North wall and there were no issues with those additions.

Once we made these additions I made the drawing a work set and we as a class have tried to make that work. But once I had a few people using the work set, the file started to fail in GBS again. This time there was too many variables, people, things that were changed, to fix it. Luckily I made a copy of my original file before I made a work set of it. That one still works.

[Teresa.Martin]

Dear Nick;
In regards to the floors, I have not run into that as an issue. You should be able to move them up and down without any issues. I will run further tests.
In regards to changing out the walls and components. You can do this for your design, but GBS does not recognize the wall types. That is to say you might as well leave the walls as generic because there is no there...there...so to speak.
Green Building Studio is a tool for schematic design, not design development or contract documents. It gets you started without having to put too much into to model other then walls, openings, roofs, rooms and floors. When you start getting into specific types of walls, additional design elements, etc. you are really looking at a different product such as IES or Ecotect.
In regards to worksets/worksharing. Best practice on this...Create a new central file by copying it to another directory. When opening the copy, choose detach from central. This will make it a unique file.
Do a saveas, and from options choose make this the central file after save. Purge the file. Choose save and choose the compact option. You should now have a clean file that can be uploaded to GBS without issue.

Best regards,

[jstrapko]

Teresa Martin,
Thank you for responding to Nick's post.
We understand that GBS is offered as a schematic design tool. What I do not understand is why GBS templates define floor, wall, and roof surfaces as particular material assemblies. Why not simply specify an R-value for each surface and U-factor for components such as windows and doors? We have had to choose assemblies such as 8 inch concrete wall R-13 to represent a masonry cavity wall, which is not available from preset options. I am not clear on what the preset assembly descriptions add to GBS analysis.
Jim Strapko

[Teresa.Martin]

Teresa Martin,
Thank you for responding to Nick's post.
We understand that GBS is offered as a schematic design tool. What I do not understand is why GBS templates define floor, wall, and roof surfaces as particular material assemblies. Why not simply specify an R-value for each surface and U-factor for components such as windows and doors? We have had to choose assemblies such as 8 inch concrete wall R-13 to represent a masonry cavity wall, which is not available from preset options. I am not clear on what the preset assembly descriptions add to GBS analysis.
Jim Strapko

Dear Jim;
The preset assemblies are just that, presets. GBS does not currently let you add/create your own assemblies. They are a preset list based upon common assembly types. Does the list need to be expanded? Most definitely. Are they working on this? I believe so. The assemblies will change the energy stats and reports. The calculations the GBS does behind the scenes is based upon known assemblies. There is a whole lot of math involved here. Could they switch to just defining a u-value or r-value? Perhaps, but I do not know how the web service is necessarily doing all the behind the scenes calcs.

If you want to be able to define particular assemblies or make your own, you are really looking at Ecotect or IES.
You can define which preset in the GBS template that it always assumes by changing this in the project template on the website after you have created a user profile/project.
Best regards,

[jeffh]

Teresa Martin,
Thank you for responding to Nick's post.
We understand that GBS is offered as a schematic design tool. What I do not understand is why GBS templates define floor, wall, and roof surfaces as particular material assemblies. Why not simply specify an R-value for each surface and U-factor for components such as windows and doors? We have had to choose assemblies such as 8 inch concrete wall R-13 to represent a masonry cavity wall, which is not available from preset options. I am not clear on what the preset assembly descriptions add to GBS analysis.
Jim Strapko

I think Teresa's explination is basically correct. GBS is doing calculations realted to things like insolation values of materials and how much solar energy is released back into the building during a diurnal/nocturnal cycle. This is just one example. For this reason a simple R value can't capture the nature of the materials used to derive the R value. I am for sure not an expert on the exact calculations going on but this is my understanding of what is going on.

[jstrapko]

This quarter is completed next week. Our final design for the fire station project is attached. We included shading at curved curtainwall and need more but could not figure out how to draw it. Unfinished work such as additional shading and energy analysis will wait for a fresh group of students next quarter. They will build on the good work of this group.
Thanks to all for advice.
Jim Strapko

[Teresa.Martin]

It looks great! Keep us all in the loop!
Best regards,

[jstrapko]

I should mention that GBS contributed to our design process exactly as intended. We ran schematic alternatives that showed our addition, even with substantial curtainwall, did not increase SUV count. We offset increased building surface area and glass with roof insulation over the entire building and GBS yielded fewer SUVs. Without Green Building Studio, we would have answered energy consumption questions by guessing.
Some of my current students may continue using GBS during their next quarter for schematic design of a multistory office building. Today their final test in this class involves producing GBS reports for a base run and alternative.
Thanks Again
Jim Strapko

[davido.204584]

Bringing this back up again, but it'd be great to hear more from your student's work with GBS.

I'd really love to use it, but I'm finding more and more that the models that I get from architects will not even upload to GBS no matter how hard I try. It's frustrating because there is a definite advantage we could gain from uploading our Revit model and get an eQuest model back. Any further insight you may come across, I'd greatly appreciate it!

[Mike Sealander]

Davido:
A good GBS export is not always a good Revit architecture model. In other words, don't get seduced into thinking a Revit model being put together for construction documents is the best thing to send to GBS

[davido.204584]

Davido:
A good GBS export is not always a good Revit architecture model. In other words, don't get seduced into thinking a Revit model being put together for construction documents is the best thing to send to GBS

I absolutely agree, It's FAR easier to work with an SD building as opposed to any other. I delete ceilings, fixtures, casework, etc. But the problem that I constantly run into is voids in the buildings, eg. walls that don't go all the way to the roof, gaps in floors, and so on. And what usually ends up happening is we build a model in eQuest anyways because there would be no time saved in fixing the model, uploading to GBS, and then obtaining the .inp file for eQuest and still have the possibility of needing to fix certain aspects of the equest model.

There's a great potential here that would not only save a lot of time, but give the ability to use eQuest as a better design aid early in the process.

[Mike Sealander]

I've been meaning to look into eQuest. do you really like it?

[davido.204584]

I've been meaning to look into eQuest. do you really like it?

Yes and no, there are little quirks about it that can cause sudden fists full of hair (nothing specific really, just your run-of-the-mill software issues).

It has a great user interface, but the largest challenge is building the model in eQuest, it's time consuming to say the least. Revit -> GBS -> eQuest would greatly reduce time IF it was an easy process, but I have yet to work with a building that doesn't need a tremendous amount of work done.