OpenCDE is a set of open web interfaces (APIs) from buildingSMART International that let a common data environment and the tools around it talk to each other without vendor-specific connections. Model servers are systems that store building models as data, object by object, so that people and programs can query, version and exchange parts of a model rather than whole files. The two ideas meet where a project wants its information to move between platforms without exporting and re-uploading files by hand.
At a glance
| Maintained by | buildingSMART International (OpenCDE APIs) |
| Main APIs | Foundation API (authentication, discovery), BCF API (issues), Documents API (files and their metadata) |
| Model servers | Store models as objects; examples include open-source and commercial products |
| Solves | Moving issues, documents and model data between tools without manual export |
| Status | BCF API widely implemented; Documents API newer, adoption growing |
The parts
- Foundation API: how a tool finds a CDE's services and signs in to it.
- BCF API: issues (topics, comments, viewpoints) shared live between a viewer, an authoring tool and a CDE, instead of exchanging BCF files.
- Documents API: uploading and downloading documents with their metadata, so a tool can publish straight to the CDE.
- Model servers: a database of model objects with an interface for queries ("all fire doors on level 2") and for changes between versions.
How it is used on projects
The most common use is the BCF API: issues raised in a coordination tool appear in the authoring tool and in the CDE without anyone emailing a file. Model servers are used where many parties need the same live model data, such as on large programmes, in asset management or behind digital twin platforms. In both cases the gain is fewer manual copies and fewer out-of-date versions.
Variations
- Open APIs (OpenCDE) work across vendors that implement them.
- Vendor APIs offer the same kind of connection within one ecosystem.
- Open-source model servers and libraries let teams build their own; commercial platforms offer hosted ones.
Common misunderstandings
- "An API replaces the CDE workflow." Statuses, approvals and naming rules still apply; the API only moves the information.
- "A model server means no more files." Contracts and archives still need issued, fixed versions.
- "Every CDE supports OpenCDE." Check which APIs, and which versions, each platform implements.
Where to read more
buildingSMART International's OpenCDE and BCF API pages (with the public API specifications); the CDE and BCF entries on this site; your CDE vendor's integration documentation.