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BCF intro

buildingSMART has adopted the Open BIM Collaboration Format (BCF) as a buildingSMART standard. This page contains introductory information.

Introduction

The BCF development includes both,  a XML file format as well as a RESTful webservice. 

The BIM Collaboration Format (BCF) is an open file XML format "bcfXML" that supports workflow communication in BIM processes.

The RESTful webservice "bcfAPI" enables software applications to exchange BCF data seamlessly in BIM workflows.

 

Background

Before 2010, endusers, who wanted to exchange issues, proposals and change requests in BIM-data-models, always had to exchange the whole BIM-model as a bulk data. The receiver had to compare different releases of the BIM-model in order to filter the requests from the sender. As a much more efficient way to support this effort the idea of developing an open standard to enable BIM-workflow communication between different software tools had been proposed to buildingSMART. In 2010, Tekla and Solibri came up with an initial XML schema, called "bcfXML v1", to encode messages containing BIM-topics (e.g. issues, proposals, change requests, ...) addressed in BIM-data-models. The implication was to boost the degree of collaboration in BIM-workflows by only exchanging the lean topics and not the entire bulk BIM-data model between software applications. "bcfXML v1"  became implemented by several software packages and valuable experiences could be gained by using it in BIM-based projects.
In 2013, based on these experiences a task force, lead by Solibri, was established in buildingSMART's ISG (Implementer Support Group) to enhance "bcfXML v1" in certain focal points like flexibility related to project specific aspects, the possibility to exchange maschine readable BCF-Topics with attached BIM-Snippets (small components of a BIM-model), attached multiple viewpoints, ... . Finally and after intense public review "bcfXML v2" became released and was adopted by buildingSMART in October 2014.

In 2014, as a second major objective of the BCF-task force, the BCF-webservice "bcfAPI" was introduced by iabi (Institute of applied Building Informatics). The idea behind this is to exchange BCF-Topics not only manually or by e-mail attachments via bcfXML-files, but seamlessly and automated via a standardized RESTful API "bcfAPI".

Released in March 2017, "bcfXML v2.1" and "bcfAPI v2.1" are the newest versions adopted by buildingSMART. BCF v2.0, which has a strong focus on maintaining backwards compatibility with the first version of BCF, did have some leftover elements present that were necessary for compliance with BCF v1.0 but did not fit right into the new standard. These also caused occasionally confusion with implementers and users. Such elements where removed or replaced in v2.1.

  • The BCF XML and BCF APIs version numbers were harmonized.
  • Implementer agreements on the viewpoints have been defined so that every viewer represents the viewpoint as closely to how the originating application created it as possible. An overhaul of the geometric components data structure is much more storage efficient regarding real life exchange scenarios.
  • Instead of using a customized authentication process for the BCF API, industry standards were referenced and therefore should greatly reduce implementation efforts both for server and client developers.
  • Resource authorization is now part of the API so that servers can clearly communicate which data a user has access to and which operations the user is permitted.
  • Historical records to audit changes throughout a project have now been incorporated in the BCF API.

 

Links

bcfXML v2.1 GitHub
bcfAPI v2.1 GitHub