Adding to what has been already said - Our early studies took a single staff member ~40 hours to do LCA modeling, but this has trended lower with each new project. We’ve reached a point where we’re able to do most Tally models here from anywhere between 4 and 16 hours per model. This depends on model complexity, BIM cleanliness, naming standards, and how consistent materials are across projects. We like to argue that the Tally process is part of the QA/QC process, as it requires people to really look at model health and project specs. If it’s hard to enter data for Tally, it’s probably not clear yet.
Tally is an easy tool to pick up - I handle training at the office, and within 30 minutes, most people can get up and running on the tool and know 90% of the quirks. What’s not immediately apparent are the quirks and limitations of Tally and how to work with them. For instance, complex curtain wall families and generic models do not report well (if at all). We’ve learned over time that it’s better to exclude things that don’t report correctly and add rough volumes of material to our model that represent the excluded geometry. This requires manual take offs of materials, which is slow for the LCA process, but allows our project teams to continue working quickly on the models. There are a lot of trade offs like this. In general, some things that we do to try and speed the process up is to remind project teams to use consistent material naming, identifying things that Tally is looking for to speed up the material application process. An example is identifying stud depths in their material names and specifying which studs contain insulation in their cavity - ie “6” metal stud w/ batt insulation." It’s also helpful that the number of LCA practitioners has grown quickly, and there is a large amount of support in user groups and forums like this.
On structural models - It’s extremely helpful to have a structural consultant who works in Revit and can handle their own Tally model. They have a better understanding of reinforcement and concrete strengths, so they can better apply it to their model definitions. It also allows the Tally data to live in their model, as opposed to having someone on your end have to enter it into a split off model (we don’t work in our consultant’s models, so if we have to enter structural data, we create a new central copy).
On MEP, Interiors, and FFE - adding onto Bob’s comments - Tally is not really designed for these. Some interiors track - carpet tiles and general wall finishes - but anything that is custom, especially custom work that’s built as a 3d family and not a native revit wall or floor, will generally not Tally. When we track them, we have to develop a side process involving manual take offs and spread sheets.
Good luck with this. I think it’s a worthy rabbit hole to go down, but it is a very deep one.