The Urban Engine supports two distinct types of data – Base Model Data and Pro Mode Data. The purpose of each type is quite different.
Base model data is fast loading, high performance, supports millions of objects and is easy to access. It is intended to be ‘read only’ and is a single source of truth for all users. Base model data cannot be actively selected or modified aside from pre-configured options, or temporarily cut out with pro-mode tools.
Pro Mode data is intended to be interactively edited within the software at a rapid pace. While pro mode data can be saved and sorted into layers, all changes are intended to be temporary and are designed to be accessed locally by that user only. Layers can be shared to other users via UCE files, however there is no support for a single source of truth that can be accessed by many users. Pro Mode is not designed to store large quantities of options or objects without considerable performance overhead. Any changes intended to be permanent or distributed to multiple users for should be processed back into the Base Model.
The performance optimizations used by the Urban Engine to allow Base Model content to achieve such high performance and easy access requires offline processing and data structures that do not facilitate the interactive editing Pro Mode content requires. If these optimizations were applied to Pro Mode content, they would no longer be selectable or editable on-the-fly.
Base Model Content vs Pro Mode Content table
| Base Model Content | Pro Mode Content | |
| Number of objects supported | Millions | Hundreds |
| Background loading | Yes | No |
| Single source of truth for all users | Yes | No |
| Optioneering | Yes | No, but can be simulated with layer / object management |
| High Performance LOD system | Yes | No |
| Permanent storage of model changes | Yes | No |
| Easy distribution to multiple users | Yes | No |
| Interactive editing | No | Yes |