3D Viewerプラグインの説明見ると、
The Lite Viewer prioritizes .glb and .glTF files with robust features, while the Advanced Viewer, supporting .obj, .3ds, .stl, .ply, .gltf, .off, .3dm, .fbx, .dae, .wrl, .3mf, amf, ifc, .brep, .step, .iges, .fcstd, .bim file types, has a more streamlined functionality.
とあるので Advanced Viewer はいろいろな形式に対応してるらしいが、3D sourceには glb, glTF しかアカンと書いてある。Blenderでglb 出力して実験続行。
ビューイングの基点がどこに行っちゃうのかようわからん。
別のプラグイン（Threepress）も試してみる。ビューイングはこっちがまともな気がするけどホイールの拡大縮小が効かない…
{"model_id":"55","controls":"orbit","light":"sun","light_pos":"1,1,0","intensity":"5","cam_pos":"1,1,1","has_lensflare":"true","zoom_speed":"5","rotate_scene":"true","rotate_speed":"3","bg_color":"linear-gradient(45deg,lightblue,white)","model":{"ID":"55","post_author":"1","post_date":"2025-01-02 16:25:28","post_date_gmt":"2025-01-02 07:25:28","post_content":"","post_title":"Sample Car for Threepress","post_excerpt":"","post_status":"inherit","comment_status":"open","ping_status":"closed","post_password":"","post_name":"sample-car-for-threepress","to_ping":"","pinged":"","post_modified":"2025-01-02 16:25:28","post_modified_gmt":"2025-01-02 07:25:28","post_content_filtered":"","post_parent":"0","guid":"https:\/\/sakku.org\/wp-content\/uploads\/2025\/01\/flying_car.glb","menu_order":"0","post_type":"attachment","post_mime_type":"model\/gltf-binary","comment_count":"0"}}