Sketchfab is an excellent platform that lets you upload 3D models and also provides a nice viewing experience. This recipe is similar to Embed external video stream. It will let you embed an external Sketchfab 3D object with the viewer into a CONTENTdm item page.
const url = embedSketchfab.getUrl('source');
And of course replace the collection alias with the your designated collection alias:
let collectionScope = [ 'p15700coll2' ];
Then you should be able to view the Sketchfab object in your CONTENTdm site.