[nikonp]

Rerun ceo here, thanks for jumping into the discussion here Adrian!

First of, want to really highlight that MCAP is a great container format for robotics message recordings. We (like most of the robotics community) see it as the natural evolution of the rosbag format (co-created a while back by one of our team members).

To add onto some of the differences between Rerun and Foxglove, the Rerun open source project is focused on a viewer that runs completely client side. It's written end-to-end in Rust for maximum speed and portability. That means it can run fully natively for maximum speed (e.g. utilizing native threads and rendering APIs), and in the browser via wasm. You can even embed Rerun visualization in your own web apps and use it inline in python notebooks.

I would also highlight the SDK, which lets you log / send data easily from your own code without up front declaring a message schema. This makes it much easier to also use for quick debugging etc (although some of the largest companies in the world use it to build large sets of different internal visualization heavy tools as well).

On the data model side we've focused on developing what you might label a language or semantic data model. We believe this gives users significantly more power and control than "only" orienting around robotics messages. I think that's why you'll see Rerun being used in a lot more contexts than viewing Robotics messages (although that's a big use case as well). In order to really make use of that data model (with high performance) we've had to develop a new database query engine and a lot of other craziness.

We do have a cloud data platform in the works that leans heavily on our semantic model and query engine. It will have a different take to Foxglove's, with a much broader view of the full data lifecycle for embodied AI.