If you read back through earlier comments on this post, you'll see the Lumion users create the model in SH3D and then export it in OBJ format. (Since light sources don't export, you'll have to create those within Lumion -- but you'd probably want to, anyway, as most external renderers give you access to a wider range of light types than are currently supported by SH3D.)

In theory, you can use this workflow with virtually any major ray-tracing or rendering application.