Error on play: "Object reference not set to an instance of an object"

[matthewrbrennan]

Getting this error in Unity 2022.3.9:
NullReferenceException: Object reference not set to an instance of an object
GaussianSplatRenderer.OnPreCullCamera (UnityEngine.Camera cam) (at Assets/GaussianSplatting/Scripts/GaussianSplatRenderer.cs:345)
UnityEngine.Camera.FireOnPreCull (UnityEngine.Camera cam) (at <10871f9e312b442cb78b9b97db88fdcb>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)

I'm using a pointcloud.ply from NerfStudio with the transforms.json renamed to the expected "cameras.json"

Not sure where I went wrong, but any guidance would be much appreciated!

[carlosnavarro-cn]

I have the same issue. The content of my transforms.json is formatted very differently from your camera.json. Is there a practical way to match the content?

[aras-p]

@matthewrbrennan my guess is that there was some other error before that, that causes the later nullref exception. Anything else in the previous console error messages?

@carlosnavarro-cn I only made it support cameras.json files as I found them among the Gaussian Splatting paper data files. If you have something that is different format, and you'd like it to be supported by this, then feel free to either send a pull request, or at least show how your file looks like.

[matthewrbrennan]

@aras-p So there was! It jumped so quickly to "999+ errors" I didn't think to scroll all the way to the first one, which was this:

Exception: InputVertex size mismatch, we expect 248 file has 27
GaussianSplatRenderer.LoadPLYSplatFile (System.String folder, System.Boolean use30k) (at Assets/GaussianSplatting/Scripts/GaussianSplatRenderer.cs:169)
GaussianSplatRenderer.OnEnable () (at Assets/GaussianSplatting/Scripts/GaussianSplatRenderer.cs:257)

Again, I'm using a .ply output from NerfStudio (it's about ~180 megabytes) - I don't recall exactly what settings I had at export, but there was nothing that jumped out at me as potentially gamechanging.

Do the images (jpegs) need to be in the folder as well?

Thanks Aras!

[aras-p]

@matthewrbrennan "Exception: InputVertex size mismatch, we expect 248 file has 27" would mean the file is not a PLY file containing Gaussian Splats, but rather a file containing something else (perhaps just a sparse point cloud?)

[matthewrbrennan]

@aras-p OK - so that means simply exporting a PLY pointcloud from Nerfstudio won't work (duh) - guess I've got to do some more reading up. Thanks!

edit:
After some more reading - it sounds like I just need to go through the original paper... 2nd "duh" of the day.

For anyone in the future: @carlosnavarro-cn came to the same conclusion below - follow the steps outlined in the paper to get an appropriate pointcloud!

[carlosnavarro-cn]

@carlosnavarro-cn I only made it support cameras.json files as I found them among the Gaussian Splatting paper data files. If you have something that is different format, and you'd like it to be supported by this, then feel free to either send a pull request, or at least show how your file looks like.

Thank you, @aras-p ! I realized I couldn't just use a NeRF transforms.json, but needed to train a Gaussian Splatting scene to get the proper camera.json. I got it working now!