# How does IFC work with existing classification systems such as Omniclass, Uniformat, etc? **URL:** \ **Category:** Developers\ **Created:** [December 30, 2018, 5:40am UTC](https://forums.buildingsmart.org/t/how-does-ifc-work-with-existing-classification-systems-such-as-omniclass-uniformat-etc/804 "2018-12-30T05:40:35Z")\ **Posts on this page:** 1\ **Showing post:** 11
**Author:** ![michelangelo](https://avatars.discourse-cdn.com/v4/letter/m/ecae2f/32.png) [@michelangelo](https://forums.buildingsmart.org/u/michelangelo)\ **Post date:** [March 14, 2019, 11:19am UTC](https://forums.buildingsmart.org/t/how-does-ifc-work-with-existing-classification-systems-such-as-omniclass-uniformat-etc/804/11 "2019-03-14T11:19:23Z")
I completely agree with the precise analysis by @stefkeB regarding the current IfcClassification and IfcClassificationReference support (or lack of, as pointed out by @TLiebich) from applications. However, I would add usBIM.viewer+ to the list. It is a free IFC viewer and editor that regarding the classification systems has the capability to take an already existing IFC file (2X3 or 4) and add/update/remove classification information based on common systems (Omniclass, Uniclass, etc.) or to add a custom schema, and to filter entities based on such informations. More info on another topic [here](https://forums.buildingsmart.org/t/usbim-viewer-free-ifc-editor/1144). --- _[View the full topic](https://forums.buildingsmart.org/t/how-does-ifc-work-with-existing-classification-systems-such-as-omniclass-uniformat-etc/804)._