We have added a unit toggle between metric <> imperial units in our viewer, so any user can now change units on the fly.
The model's default unit setting is set by its geolocation. For example, if the address of the model is in New York, USA, the model will by default load in imperial units.
To set your model's address: log-in to your account > go to the model, simply click the gear icon on the bottom left of your viewer and enter the address in the pop-up "Scene settings" window, then click "Save".
If you want to share your model with someone that prefers to view it in different units, you can also customize it via the Share settings.