# What is BCF?

BCF, the BIM Collaboration Format, is an open standard for passing issues between BIM tools. A BCF file holds topics, each with a title, a status, comments, a picture and the elements it is about, named by their GlobalIds, so an authoring or coordination tool can show the issue on the model. IFC Checker writes BCF 2.1.

Updated 1 November 2026

## What a topic holds

A topic is one issue. It has a title, a type such as Issue or Warning, a status, a priority, who it is for, a due date, labels, a description and comments. It also has one or more viewpoints, each a picture with the camera it was taken from, and it names the elements it is about by their GlobalId, so a tool that has the same model can show them.

## What IFC Checker writes

IFC Checker writes BCF 2.1. One topic stands for one specification and group of requirements of the test, listing its elements and what each fails, with a picture of them from the 3D view. A topic keeps the same ID every time the same model is checked against the same test, and a summary topic gives the index and the counts. What your own tool does when it opens the file depends on the tool. Reading a BCF back into IFC Checker is not in this version.

## Try it in IFC Checker

1. [Run a check](https://ifcchecker.com/help/check-a-model/). The issues it found are the topics of **BCF topics** on **Results**.
2. Choose **Download BCF** under the **Model** table to write the file, and open it in your authoring or coordination tool ([How do I export BCF issues, Excel or CSV?](https://ifcchecker.com/help/export-results/)).

## Where to read more

buildingSMART publishes the standard, its versions and its documentation:

- [buildingSMART: BIM Collaboration Format (BCF)](https://technical.buildingsmart.org/standards/bcf/)
- [BCF on GitHub](https://github.com/buildingSMART/BCF-XML), with its schemas and its documentation

## Keep reading

Next: [Which IFC and IDS versions are read?](https://ifcchecker.com/help/ifc-versions/)

Related:

- [How do I use the BCF topics section?](https://ifcchecker.com/help/bcf-topics/)
- [How do I export BCF issues, Excel or CSV?](https://ifcchecker.com/help/export-results/)
- [What are BIM and openBIM?](https://ifcchecker.com/help/what-is-openbim/)

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