Iestyn Lloyd-Wilkins

Saving 6D.ai’s mesh at runtime as an OBJ in Unity

For anyone who’s wondering how to save the meshes generated by 6d.ai, it’s pretty straightforward. I’ve seen a few people asking and no definitive answer, so thought I’d write it up in case anyone searching for this found it useful.

The steps are basically:

1. Combine the chunks into one mesh.
   I used Unity’s built-in Combine Meshes. You can see a sample of the code here, which I adapted.
2. Save the mesh locally.
   I used obj-unity3d to save the mesh as an obj to Application.persistentDataPath.
3. Access the mesh.
   Currently 6d.ai is iOS only, so plug your iOS device in, open XCode, and do the following:
   Window>Devices and Simulators>Select your App> Press the cog>Download container > Save > Navigate to the container >Right click >Show package contents>App Data>Documents. Your file will be there!
   You could also upload the local OBJ to a cloud storage solution for easier access. I did this using Firebase, but that’s a post for another time.

A hacky code sample that might help you out:

//Get a reference to the SDMesh
 SDMesh sdMesh = FindObjectOfType<SDMesh>();
 
 //combine the meshes
 MeshFilter[] meshFilters = sdMesh.GetComponentsInChildren<MeshFilter>();
 CombineInstance[] combine = new CombineInstance[meshFilters.Length];
 int i = 0;
 while (i < meshFilters.Length)
 {
 Debug.Log("combining.."+meshFilters[i].gameObject.transform.name);
 combine[i].mesh = meshFilters[i].sharedMesh;
 combine[i].transform = meshFilters[i].transform.localToWorldMatrix;
 i++;
 }
 Mesh combinedMesh = new Mesh();
 combinedMesh.CombineMeshes(combine);
 
 //save the mesh
 OBJData data = combinedMesh.EncodeOBJ();
 string filepath = Application.persistentDataPath + "/Obj_" + UnityEngine.Random.Range(0, 10000) + ".obj";
 var lStream = new FileStream(filepath, FileMode.Create);
 OBJLoader.ExportOBJ(data, lStream);
 lStream.Close();

Originally published at https://medium.com on November 24, 2018.