SceneNode to MeshGeometryModel3D

It seems the examples show to get a MeshGeometryModel3D from a HelixToolkitScene one would do this:

if(helixScene.Root.Items[0] is MeshNode mesh)
{
    var model = new MeshGeometryModel3D()
        {
            Geometry = mesh.Geometry,
            Material = mesh.Material
        }
}

But with UWP when trying to create the MeshNode mesh variable it does not work. I get the following error:

An expression of ‘SceneNode’ cannot be handled by a pattern of type ‘MeshNode’.

I’m getting everything I need. If I use it as a SceneNode I can assign it to a object type property and bind to that property from the Viewport using a converter to show it. But I’d like to “convert” it to a MeshGeometryModel3D because all the examples use MeshGeometryModel3D and it’s quite confusing trying to follow the examples but then failing because it’s not the same type.

[JuandreG]

I need to do xaml bindings yes.

[jeromegold]

Hi @chrkon and @KvardekDu. Thanks for the replies. So my experience with .net 5.0 and a wpf app has been the following:

I used the HelixToolkit.SharpDX.WPF package for the wpf app. (not the core) I had to individually install each of the SharpDX packages eg. SharpDX.mathematics, etc. And this seemed to work and in my xaml I could use Viewport3DX>, etc and render a scene. Basically the HelixToolkit.ShaprDx.Wpf was using the older .NETFramework to run off and was doing this automatically, even though the target framework under project settings for my app is .NET 5.0…

But then I ran into a problem. I wanted to load my models using assimp but nuget kept installing the Core 3.1 version Helixtoolkit.SharpDx.Assimp and this didn’t work with my Helixtoolkit.SharpDx.Wpf scenenode.

I did some reading and nuget seems to make the decision by itself which version of a package to install. I wanted the net45 version of Helixtoolkit.SharpDx.Assimp but it kept installing core 3.1.

So I first tried uninstalling all the HelixToolKit.SharpDx.Wpf packages and the other SharpDX packages and went to install HelixToolkit.SharpDX.Core.WPF. But the Core.WPF didn’t seem to work with my .NET 5.0 app. I tried a few times with .NET Core Wpf but ccouldn’t seem to make things work. I feel like I probably could try a few other things to test if Core.WPF really doesn’t work witn .NET 5.0 (eg. try a barebones WPF .NET 5.0 project) but kind of gave up after a whiile.

I tried other ways of installing the net45 version of Helixtoolkit.SharpDx.Assimp eg. in the .csproj file you can specify the packages you want to install and make a condition on the target framework, but this didn’t work.

Even though nuget forced Helixtoolkit.SharpDx.Assimp to target Core 3.1 when nuget installs the package, it installs all the versions in different subfolders. So the net45 subfolder existed on my machine, and I just created a reference to that and got things working.

In case anyone runs into the same prob.