Rhino3dmIO (File3dm.Objects.ToList() returns the right count but with all null values)

openNURBS
1

Hi,
I am reading Rhino file using Rhino3dmIO module inside Revit. It reads the file but upon calling File3dm.Objects.ToList() returns all objects as nulls. I want to get InstanceReferenceGeometriy and InstanceDefinitionGeometry even after using filter it returns only nulls.

It seems there is a problem with my computer…same code worked on another computer :thinking:dont know what’s happening exactly.

find attached image.

Thanks!

image
image1841Ă—832 137 KB

3

Could it be a possible conflict between the 3dm reader that is shipped with Revit, and the one that is loaded with Rhino.Inside.Revit?

5

it seems that Rhino.RhinoDoc.ActiveDoc.Object.ToList() always returns null values but if you foreach or do something like Rhino.RhinoDoc.ActiveDoc.Object.Select(x=>x) it works fine.

Thanks!

1 Like
6

I am having the same problem but this is within a net6 solution with no Revit context. Was there a solution to this thread?

7

Hi @daniel4dev,

Are you using the C# version of Rhino3dm? As always, sample code that doesn’t work for you is helpful.

Thanks,

– Dale

8

Hi @dale,

Yes we are using the C# version of Rhino3dm, in all snippets I put below file is a File3dm type.

So at first we just tried to do var items = file.Objects.ToList() but got the error from above. Then I took the advice from above and tried var items = file.Objects.Select(x => x).ToList() but still got the error, but I think that’s because LINQ was simplifying expression so the select was essentially doing nothing. Then finally when I do var items = file.Objects.Where(x => true).ToList() I no longer get the error.

I think there might be something around the type of file.Objects inherits both from IList and IEnumerable and the IList implementation is failing so I need to force LINQ to query on the IEnumerable and casting file.Objects to IEnumerable doesn’t work either because LINQ is just too smart :laughing:

Thanks,
Daniel

9

When I use LINQ for File3dm.Objects I get a NullReferenceException.
Below is an example when the exception is thrown:

File3dm d = new File3dm();
d.Objects.AddLine(new Point3d(), new Point3d(1,1,1));

for (int i = 0; i < d.Objects.Count; i++)
{
File3dmObject docObj = d.Objects.ElementAt(i);
Console.WriteLine(docObj.Id);
}

I am using .Net runtime version 8 on windows 11. The Rhino 3dm version used is 8.9.0
Is there some reason why it is no longer possible to use LINQ for File3dm.Objects.

10

This is a known bug and is logged here:

RH-80461 File3dmObjectTable returns different values using linq vs iterator

As a workaround, use this getter function:

bool TryGetElementAt(File3dm doc, int index, out object element)
{
    element = default;
    int i = 0;
    foreach (object dobj in doc.Objects)
    {
        if (i == index)
        {
            element = dobj;
            return true;
        }

        i++;
    }

    return false;
}

using (File3dm doc = File3dm.Read(tempfile))
{
    if (TryGetElementAt(doc, 0, out object element))
    {
        Console.WriteLine(element.ToString());
    }
}
12

Thanks for your response. I will adjust my code with your workaround. What is special is that in an earlier version of the rhino3dm it did work. I only noticed when I upgraded that it no longer works.
In any case, thanks for your help.