This tool is being developed by the WoW community for the WoW community and as such won't have watermarks all over it but will likely also be more unstable/bleeding edge. Currently it supports rendering most M2 models (smaller more complex models, characters unsupported), WMO models (larger models) and ADT files (terrain files with WMOs and M2s).
These parts of it are open source:

• Model viewer itself
• DBC backend (used for texture lookups)
• CASC backend (serves files)

Requirements

This requires a browser that supports both WebAssembly (see list here) and WebGL 2.0 (see list here). If your browser does not support this the modelviewer will definitely get upset and will definitely throw errors towards your general direction. We're aware this is not always supported on some configurations, but are hopeful it will be in the future!

Controls

SHIFT-Z hides the UI.
Spacebar pauses the current model (entirely, including rotation and stuff).

For ADTs and WMOs, the model viewer uses a free-roam camera. It can be controlled via dragging the mouse and WASD keys. Holding SHIFT increases camera speed. Pressing O (the letter O, not zero) returns the camera to position 0 0 0.

For M2s, the model viewer uses a rotational camera. You can rotate the model by dragging the mouse and zoom out with the scroll wheel. If skins/animations are available, a menu will pop up with options for these.

Issues

This modelviewer (and especially the UI) is still a heavy work in progress. Many bugs will appear. Report any issues/feature requests via GitHub by clicking the "Report issues" button or via Discord by joining through the link in the menu.

Embed

An embeddable version of the modelviewer is available , but how exactly/if it will continue to work (or how costs will be dealt with if it gets popular) is still to be decided. Please contact me if you want to embed it. If you do, keep in mind it is still WIP/experimental and to not rely on it in any way.