Use only SI units in exhange

[pasi-paasiala]

Description of the proposal:

Use only metric units in IFC. For example, have all length values as meters.

What do we win:

• Reading of IFC is simplified. You don't need to convert from exotic units to your internal units.
• Precision concerns can be thought of in one go: We can advice, for example, how to model very large projects (infrastructure)

What do we loose

• Nothing, the user of the reading application can use whatever display units they want

Schema impact:

• Schema is simplified

Instance model impact:

• Simpler files

Backwards compatible:

• no

Automatic migration possible: ?

Additional implications:

Note that not all points need to be satisfied! Backwards compatibility and file size are not concerns.

[pasi-paasiala]

In the Vilnius ISG meeting we had a discussion about this and it was proposed that we could have a "preferred" display unit added. I don't mind.

[Moult]

@pasi-paasiala does this mean that the proposal has been accepted? (i.e. only SI units in exchange, with a new way to assign a preferred display unit)

If so, I really, really, really +1 this.