Working with 3D data is among the more challenging tasks when editing OpenStreetMap. OSM2World can make it easier by providing a 3D preview which serves as intuitive feedback and makes any mapping errors imediately visible.
On the web
The OSM2World Object Viewer offers a web-based standalone tool to view any object from the OpenStreetMap database in 3D, it is available no matter which app you use to contribute to OSM. It also lets you share links to the rendered models with other community members for discussion.
The viewer is available at osm2world.org/object.
For the most part, it will render data which has already been uploaded to OSM. However, the ability to change the rendered object’s tags gives you some ability to quickly try things out. Unlike the OSM2World WebGL demo (which is updated weekly), it pulls fresh data on demand to provide immediate feedback after an edit has been uploaded.
To use it on an existing object, add the ID of the OSM element to the URL like this:
https://osm2world.org/object?id=r1260102
On the desktop
OSM2World can be used as a stand-alone tool on your Windows, Linux or Mac computer. You can run it alongside your local editor (such as JOSM or Merkaartor). Save your current edits as an .osm file and open that file (File → Open, or just drag it onto OSM2World’s window). You will be presented with an interactive 3D rendering which you can explore freely. After making and saving additional changes in your editor, you can quickly reload the file in OSM2World using File → Reload or Ctrl+R.
Compared to using the web-based object viewer, this has the benefit of allowing you to view data before uploading it to the OpenStreetMap database. It also gives you access to other OSM2World functionality, such as exporting the 3D models.
See this OSM wiki page for instructions on how to install OSM2World on your machine.