Quantity takeoff with BIMcollab ZOOM and abstractBIM

In the next articles, I showcase workflows for quantity takeoff utilizing the unique properties of the consistent abstract BIM in the context of different BIM tools.

The first article will use BIMcollab ZOOM because:

• It's a powerful tool, yet easy to use.
• It's affordable, with a network license costing only 900€ and a single license costing only 720€
• It has robust reporting features that, once defined, can be rolled out in the whole organization via BIM collab, the issue management platform. This will cost extra, but this easy rollout can be helpful for a bigger organization.

When introducing BIMcollab, I often say it's the "Volkswagen." Solibri is more powerful, but not everybody needs a Porsche to move from A to B. So it's a great solid tool I love to work with, and now it's my go-to BIM Viewer.

What is the abstractBIM

If you already know the abstractBIM, please skip this chapter. When working for a design-build company, I tried to automate the quantity takeoff, and I failed because the models were:

1. Too inconsistent in terms of metadata.
2. Every company had its modeling style, making it hard to get comparable takeoffs.
3. Came too late.

So, I looked at the models and realized that the spaces, the windows, and the doors were usable and consistent. Knowing this, I thought:

Ok, an interior wall is just a wall between two spaces; when I know the space, I can teach the computer to calculate the wall.

A few years later, we now offer this as a service.

1. You upload the architectural BIM as an IFC file with Spaces.
2. Select an output quality (I recommend QTO).
3. A few minutes later, you get a new consistent model with walls, slabs, coverings, and back.

We guarantee that the elements are all named consistently, and we calculate a few unique attributes like:

• Every wall/covering/window/door knows its spatial relationship to its bordering space. We will see later how we can use this.
• Every exterior covering, window, and door knows the direction it's facing.
• The quantities are calculated according to the IFC standard.
• We remove all duplicate elements.
• We calculate a Gross Volume per story.

How QTO with BIMcollab works

After getting the abstractBIM IFC, you can open it in BIMcollab, use these predefined rulesets to get the main quantities, and use the calculation tool of your choice. So this can reduce the effort for a quantity takeoff tremendously. As the model quality from the abstractBIM is always the same, once the rulesets are defined, they are reusable.

This means you abstract your model, you open it in BIMcollab and your rulesets work. See more in these pictures:

Using relationship data

When we calculate walls, we split them at every space border. Doing this guarantees that every wall relates to precisely two spaces.

If the IfcSpace: LongName attribute contains a roommate, we use this to write the space relationship in the property "ePset_abstractBIM:SpaceLongName"

Now, if you want to, you can define custom properties in BIMcollab using this spacial realtionsship data to define additional qualifies.

For example, a wall with a "staircase" in the name is made out of concrete and has a REI90 fire rating.

Usually, a few rules are enough to define the necessary qualities. And now the magic. Once defined, these relationships usually don't change any more.

So the architect can continue to design, the quantity surveyor exchanges the model, and the model is enriched again.

Summary & Conclusion

BIMcollab excels in terms of low entry barriers and the possibilities for a smooth rollout in the wider organization. The Smart Properties, the visualizations with the Smart Views, and the lists are extremely powerful for metadata visualization and quantity takeoff. Therefore, currently, it's my go to BIM Viewer.

When doing a quantity takeoff, sometimes these features would be nice to have:

• Manual assigning elements to Smart properties for quick and dirty measurements (You can use a workaround with the GUID) but it's not so elegant.
• Manual measurement of areas/volumes. I think BIM Vision did a great job with its measurement tools (much better than BIMcollab).
• Support for other file types, e.g. overlaying the model with a pdf 2D plan for additional information. (Use a PDF viewer in parallel)

For all these points workarounds exists. But as I said, BIMcollab is my preferred BIM Viewer for a good reason.

Don't hesitate to contact me to learn more or let me know in the comments which tool you want to use in your workflow. I'll have a look at it and write an article.