Thank you, we didn’t know about chan3d. It looks like they could be using Shapespark code (the editor screenshots looks like a localized Shapespark editor). They also include screenshots of Shapespark customers’ projects. We will be checking this further.
3D scene assets for China-based clients are hosted in China, so while access to https://cloud.shapespark.com can be slow and download of scenes created by clients outside of China can be also slow in China (for example demo scenes at www.shapespark.com), download of your own scenes should work well. With the Plus subscription plan or the perpetual license you can also create self-hosting bundles, and host the scenes from your own server.