Semantic model

First of all thanks to all those that have created and support openHAB.

For me the star of OH3 is the semantic model. I understand this is the first version and I was just wandering if there is a roadmap of how this will develop. I have a few questions.

1, Will the ontology be made extensible by the user?
2. From what I am seeing there is a hidden part of the Ontology that defines that a location tile should show badges base on the class of the equipment and points. I will call this behaviour as the published ontology does not extend to explain this just now.
a) Is this behaviour driven by the ontology or is this hard coded just now?
b) Will this “behaviours” part of the ontology be exposed in the future to allow greater user control?
3. Is there any support I can offer to help maintain and develop the ontology?



Hi there,

the semantic model isn’t really new but has been implemented in late 2018 i think.
you can read about it here: habot and semantics

to me one paragraph is very important:

According to the schema, currently you can only tag an item with one of the Location, Equipment or Point tags, but you can combine a Point tag and a Property tag on the same item.

Tagging works in the (3.x) UI and in textual configuration, also be aware there are more taggings available e.g. amazon/alexa stuff.

AFAIK openHAB is using the Eclipse SmartHome semantics/ontology so the only way to enhance/extend/add tags is to do it on the ESH side…


Thanks for the link. I can see I am late to the party.

They started with that but it is part of OH now. There is a whole GitHub issue discussing this.

  1. Short answer is no.

2.a. It’s driven by the ontology and hard coded. The ontology is just adding a little extra info to Item through tags and Group membership. The automatically generated UIs understand the ontology and shows those hard coded icons with the counts based on it’s understanding of the ontology.

2.b. You can already modify much of what is shown on the automatically generated pages by editing the page (pencil icon at upper right hand corner). And you can control how each and every element on those pages appear by editing the “default x widget” metadata on the Items. This can be particularly powerful when done on the Equipment Group as it lets you created and use a unified widget for the whole equipment instead of showing each Point item in separate rows.

  1. You’ve already seen the link to the open Issue. That’s a good place to start.

OH dropped ESH and reintegrated it into OH proper a year ago. The ontology is actually originally based on Brick ( with some updates.


Many thanks. I thought it looked similar to BRICK.