# BSDD PropertyType **URL:** \ **Category:** bSDD\ **Created:** [November 10, 2025, 1:09am UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327 "2025-11-10T01:09:01Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Jocelin](https://avatars.discourse-cdn.com/v4/letter/j/e99b99/32.png) [@Jocelin](https://forums.buildingsmart.org/u/Jocelin)\ **Post date:** [November 10, 2025, 1:09am UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/1 "2025-11-10T01:09:01Z")
Hi, I have a question on how to define on a class and specially with the PropertyType parameter that can accept two values : Property and Dependancy. I will take the exemple of the red door class. This class is define by IfcClass=IfcDoor Color=Red This class can have multiple property assigned like height and FireResistance. In that exemple, the color=red will be considered a dependency. And that property define the class. The other property are describing the class without defined them. (A red door can exist with or without FireResistance). Is it the right way to understand PropertyType ? Or should i use IsWritable ? Jocelin ---
**Author:** ![Simon](https://avatars.discourse-cdn.com/v4/letter/s/f07891/32.png) [@Simon](https://forums.buildingsmart.org/u/Simon)\ **Post date:** [November 12, 2025, 8:45am UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/2 "2025-11-12T08:45:07Z")
Jocelin, Are you asking how to define this within an IDS? If so, try something like this in the IDS editor… The model MUST contain entities that have IFC class Name IFCDoor. that MEET the following requirements -MUST HAVE property ‘Door Colour(?) of PSet ‘XXXXX’ = Red ---
**Author:** ![Jocelin](https://avatars.discourse-cdn.com/v4/letter/j/e99b99/32.png) [@Jocelin](https://forums.buildingsmart.org/u/Jocelin)\ **Post date:** [November 17, 2025, 3:45am UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/3 "2025-11-17T03:45:44Z")
No, i would like to define it in BSDD. For me, a BSDD class is defined by properties. At the same time, it define other properties. I think that PropetyType is the metadata i am looking for but the documentation is not defining “Dependency”. I found the doc here: ://technical.buildingsmart.org/services/bsdd/data-structure/ - | PropertyType | Text | | | Type of the `Property` for the `Class`: `Property` (default) or `Dependency` | | --- | --- | --- | --- | --- | | | | | | | Jocelin ---
**Author:** ![artur\_tomczak](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/artur_tomczak/32/2632_2.png) [@artur\_tomczak](https://forums.buildingsmart.org/u/artur_tomczak)\ **Post date:** [November 24, 2025, 12:58pm UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/4 "2025-11-24T12:58:31Z")
Hi @Jocelin, I’m the bSDD manager, and I will try to help. “PropertyType": “Dependency” is something that was implemented to reflect the functionality of the ISO standard, but because it was never used in practice, we are considering removing that feature in the near future. I recommend not using this attribute. According to the standard ISO12006-3: “Dependency means that the current property’s value may change if the value of one of the related properties is changed.“ Similar goal can be achieved with “ConnectedPropertyCodes” that is reflecting another standard - ISO23386. You mentioned “IsWritable” - that is rarely used as well, and I don’t know any software making use of it in practice. If you want to define a class “Red door”, easiest would be to define a class called like that. You can make those multi-property dependencies in form of specification using the IDS standard. ---
**Author:** ![Jocelin](https://avatars.discourse-cdn.com/v4/letter/j/e99b99/32.png) [@Jocelin](https://forums.buildingsmart.org/u/Jocelin)\ **Post date:** [December 5, 2025, 12:07pm UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/5 "2025-12-05T12:07:58Z")
Hi, Ok, dependency was not right thing to use. I don’t want to use IDS either to describe this relationship between an object and his property. I want to do it the other way around, manage property with BSDD and create on the go an IDS. In reality, I think I am looking for is a translation from BSDD to IDS. IDS has two principle to create a relationship between a class and a property Applicability: which has no translation in BSDD Requirements: which has a translation in BSDD I went again threw ISO12006-3, and my understanding is may be better. ISO Concept I would use the XtdFilter on the XtdSubject, in order to specify property that define my subject. That part of ISO would fit my purpose. In my previous example: Color : is a filtering property of the class with the value « Red » FireResistance : is a property of the class I may be reinventing the wheel with that… Cordialement, Jocelin Birling ---
**Author:** ![artur\_tomczak](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/artur_tomczak/32/2632_2.png) [@artur\_tomczak](https://forums.buildingsmart.org/u/artur_tomczak)\ **Post date:** [December 16, 2025, 3:50pm UTC](https://forums.buildingsmart.org/t/bsdd-propertytype/6327/6 "2025-12-16T15:50:30Z")
@Jocelin, IDS is not exactly an output of bSDD. Yes, you can use bSDD to feed your IDS specification, but you need to make some choices to achieve that. One of them is “what do I use as applicability filter, and what as actual requirements?”. The bSDD doesn’t have the XtdFilter for simplicity of use. XtdSubject is represented by Class and Property objects.