IFC5-USD Bridge

[jeancolasp]

Hi everyone, I wanted to share some work that the USDKit team, which I am involved with, has been doing around converting some of the IFC5 samples you provide into USD. This essentially serves as a proof of concept demonstrating the feasibility of such a conversion.

If your group is looking for people with experience working with USD, this might help illustrate where IFC5 could potentially benefit from leveraging the standard (and the limitations/problems we discovered in the process). USDKit itself is a privately held initiative and is not open source, although both IFC5 and USD are, of course, open standards.

I will share the information here and hope it can help spark discussion or ideas within the group.

https://www.linkedin.com/posts/activity-7420069548231487488-1C7a?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAdzxZcBqIiP1VAyhHKdPpkurFPo_LSb0r4

[aothms]

Hi @jeancolasp this kind of compatibility is definitely interesting to us. Also see my message here earlier #101 Feel free to reach if there are (technical) aspects you'd want to discuss.

[jeancolasp]

@aothms Thanks, Thomas. I will put a document together outlining our main observations: what worked in principle, and some of the relatively minor issues we had to address that stem from differences between the two standards.

As a side note (outside of this forum), is there a place where your team discusses the design motivations behind IFC5? My question is not provocative in any way; it is simply to better understand why IFC5 is considered necessary if USD could, for example, handle similar use cases. What I am looking for is information that explains why IFC is still very much needed, and what it can potentially do that USD cannot.

While looking at the IFC5 samples, we can see the component-entity-system (CES) design approach, and we recognize that USD is not designed in that way. This provides clear benefits in terms of establishing relationships between components and entities, whereas USD is more scene-building oriented. Even though classes can be attached to USD prims as metadata, concepts such as site and project do not have direct equivalents in USD.

In any case, a place where we could learn more about the objectives of IFC5 with respect to USD would be greatly appreciated, if such a resource exists.