Transitioning from Tally to OneClick LCA - best practices?

Hello carbon brain trust! We’re currently testing out OneClick LCA in our office, hoping to find a replacement for Tally LCA now that the data is getting stale. There seems to be a lot of potential for this tool, but the initial assessment has left me unimpressed. The automatic mapping has not worked at all, the automatic grouping is inconsistent - it feels like it could be useful, but at the current moment, I’m fighting with the system, and I find I’m missing some of the cleverness of Tally. For instance - if you run OneClick, how do you handle stud walls? OneClick seems to have multiple entries for very specific purposes, as opposed to Tally’s general bucket for studs, and then user defined size and spacing. Or Masonry walls? Are you creating custom private constructors for your walls to include masonry, grout, etc?

I’m sure a lot of this is user error and not being familiar with the interface, so if you’re a OneClick master, what have you found most helpful running these studies? Any good lessons for beginners?

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Hi Justin,

I’m not proficient in Tally by any means, but your assessment of the differences between Tally and OneClick is spot on. OneClick touts its automatic mapping as a really helpful tool, but unless you are modeling your Revit model (what we use for quantity exports) and assign materials/assemblies exactly to how the OneClick plug in pulls that data/info, it will never work perfectly. Instead, we found what info is actually helpful from those quantity and material exports and leverage that to assign materials using the Isolate function in the plug in tool, the drawings, and the specs. We find you need the BIM model, drawings, specs, and OneClick material quantity mappings to fully identify and assign EPDs to all materials.
OneClick has a large, evolving database of EPDs that we find you need to keep track of internally for all of your baseline materials and frequently used materials.
What we do when assigning material quantities to EPDs is have custom practices for how to properly assign materials to them. For a CMU or masonry wall for example, we of course track the appropriate masonry unit EPD, then we know the assumed amount of grout or mortar per sf (or other unit) according to relevant industry average OneClick LCA constructions (look into these, very helpful for estimating quantities like rebar, grout, mortar, etc…), then calculate the grout or mortar quantities offline and add into our model in OneClick.
This is definitely more clunky and has more steps compared to Tally, but it does allow for more customization, which we find to be very helpful since a lot of buildings/projects are quite different.
As you said, it takes a lot of trial and error to build up all of these processes in-house, but once you do and understand the pitfalls and benefits of the software, it becomes pretty powerful.

Hope this helps!


@JacobSavona this is what I was thinking we’d have to do. thank you for confirming and for the idea of using the OneClick constructions as a basis for calculation. Do you all keep a tracking document for architectural materials that commonly include additional, unmolded materials or do you find the built in constructions to be good enough?

We keep track of which assemblies require additional, unmodeled materials, then use the built-in constructions to estimate these quantities.

@JacobSavona - can I pick your brain about this more - using OneClick constructions as a basis for your calculations?

@jschwartzhoff , similar to what Jacob replied, we use a combination of the Revit model, OneClick’s Revit plug-in, excel and OneClick on the the cloud to complete the LCA. (It really becomes more than one click, but who’s counting…) We have never used the automatic mapping because when we first started using OneClick it was very black-boxy and it was mapping to EPDs that really didn’t match - with that said, their database is HUGE! and if you’re conducting a LCA for elements that may not have an industry standard EPD (like NRMCA for concrete or ASIC for steel) nor a product specific EPD it can sometimes be difficult to narrow down which product to use. We have found that using excel to keep track of everything is best and it’s easy to export/import into OneClic - which is very handy if you don’t even have a Revit model but want to do a full LCA even on a simple bay study/rough estimation of quantities.

For enclosure elements, although it’s a little more tedious, we end up breaking the assembly up into each of it’s parts for more transparent book keeping. We also have found that we need to do this because often the enclosures we do are so customized.

Hi I would suggest you check out the free course here: LCA in Autodesk Revit | One Click LCA Academy

And yes early stage models especially constructions are very handy. You can either use ready made ones or make them yourself.

@JLee_SF Sure thing! We rarely use the constructions as a full replacement for an assembly in our models, since most quantities from the Revit model and drawings are pretty accurate. We more often than not use the constructions as a guideline of what materials are typical in certain constructions (i.e. CMU walls, brick walls, SOG, SOD, etc…) to help us estimate difficult to estimate, yet important, materials like mortar and rebar.
Like you said with enclosure elements, it’s more accurate to break up the enclosure into each of it’s parts and assign EPDs from there. Definitely takes longer, but is better practice.

@jschwartzhoff @JacobSavona I completely agree with the observations being made and what has been said. While Tally makes it easy to perform takeoffs and make estimates natively within the user interface, OneClick has virtually no features for geometry handling beyond what is directly available in Revit. In our practice this means close review of the excel document before import to add missing/data/layers, as well as many in-house tools or best practices for estimating things like studs or mullions, so we can enter into the tool. We also work to track our best practices for sifting the large database and tracking our material data assumptions. For this reason we find that OneClick is way more time intensive than Tally, but that the result can be great with appropriate QAQC and best practices defined. Good luck!!

@jschwartzhoff lots of good information here. I’ve not had much success with constructions in OCL - they are clunky, easily messed up, and we barely ever do the same building section twice (probably our fault there). We a running sheet of helpful geometry tips and calculators for LCA users so we can skip the OCL constructions e.g. 0.017m3/m2 of softwood for 2x6@16"oc

I was actually wondering if we should go to Tally instead of OCL, but maybe I will reassess now

Thank you all, this is helpful and confirms my thoughts. Sounds like we need to develop a translation tool for certain materials. Not ideal, but at least we’ll be able to tie into the larger database of OCL.

Before we count Tally out, though - it sounds like Tally LCA is getting a much needed update. Hopefully there’s some life left in the tool and that one click might learn a few things from the interface.

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There’s some developments on OCL that specifically address the materials mapping points outlined above. The import process has recently been updated allowing you to upload your own Excel file (e.g. a bill of materials) which has not been formatted beforehand :

An AI based mapping tool has also been released and is live in English and other European languages.This adds additional intelligence to the import process.

hello @jschwartzhof,

I am Kostas, Lead Product Manager at One Click LCA, and our team is responsible for the Revit integration. For composite elements like stud walls, if you can don’t have all the individual material elements present in the model, you can keep the relevant Type grouped (on “Detailed scope” tab) and map the whole element to a steel stud construction (public or private).

For the mapping suggestions, we have just released an additional AI-powered mapping mechanism that currently applies when you import your data to One Click LCA. Please note that in order to get mapping suggestions in the plugin, you need to have the relevant license feature that returns also calculation results, so this might be a licensing limitation for you today.

If you are interested in discussing your experience with us, our team would be happy to jump on a call with you and discuss your findings and share with you any further suggestions on how to make the most out of the integration. For this you can contact me at

Similarly, @JacobSavona we would be happy to jump on a call with your team and get your feedback on how we can further improve the integration. If you are interested, you can contact me at