RNA

blenderApi.Rna is the path-based domain for reading and writing Blender state.

Methods

• ListAsync(path)
• GetAsync<T>(path)
• ReadArrayAsync(path)
• SetAsync<T>(path, value)
• DescribeAsync(path)
• CallAsync<T>(path, methodName, params (string Name, object? Value)[] kwargs)

List Collection Items

var objects = await blenderApi.Rna.ListAsync("bpy.context.scene.objects", ct);

Each item is an RnaItemRef that can be used for follow-up path access.

Read And Write Values

var activeObject = await blenderApi.Rna.GetAsync<RnaItemRef>(
    "bpy.context.active_object",
    ct);

var objectType = await blenderApi.Rna.GetAsync<string>(
    $"{activeObject.Path}.type",
    ct);

await blenderApi.Rna.SetAsync(
    $"{activeObject.Path}.location",
    new[] { 0.0, 0.0, 1.0 },
    ct);

Read Binary Array Values

ReadArrayAsync is for RNA array-like values that should not be expanded into JSON arrays.

It is useful for large buffers such as image pixels and other foreach_get-style values.

var size = await blenderApi.Rna.GetAsync<int[]>(
    "bpy.data.images[\"Render Result\"].size",
    ct);

var pixels = await blenderApi.Rna.ReadArrayAsync(
    "bpy.data.images[\"Render Result\"].pixels",
    ct);

// pixels.RawBytes contains the protocol binary payload.
// pixels.ElementType / Count / Shape describe how to interpret it.

ReadArrayAsync returns a BlenderArrayReadResult with:

• Path
• RnaType
• ValueType (array_buffer)
• ElementType
• Count
• Shape
• RawBytes

Current bridge element kinds include:

• bool
• int32
• float32
• uint8

For image pixel buffers, the common pattern is:

• read image size metadata with GetAsync<int[]>
• read pixel data with ReadArrayAsync(...)
• decode RawBytes using ElementType and Shape

Describe A Path

Use DescribeAsync when the UI needs metadata such as readonly state or declared type.

var description = await blenderApi.Rna.DescribeAsync(
    "bpy.context.scene.frame_current",
    ct);

Call RNA Methods

blenderApi.Rna.CallAsync<T> is for methods on RNA objects, not Blender operators.

var material = await blenderApi.Rna.CallAsync<RnaItemRef>(
    "bpy.data.materials",
    "new",
    ("name", "PreviewMaterial"));

Service Example

public sealed class MaterialService
{
    private readonly BlenderApi _blenderApi;

    public MaterialService(BlenderApi blenderApi)
    {
        _blenderApi = blenderApi;
    }

    public Task<IReadOnlyList<RnaItemRef>> ListMaterialsAsync(CancellationToken ct = default)
        => _blenderApi.Rna.ListAsync("bpy.data.materials", ct);

    public Task<string> GetMaterialNameAsync(string name, CancellationToken ct = default)
        => _blenderApi.Rna.GetAsync<string>($"bpy.data.materials[\"{name}\"].name", ct);

    public Task RenameMaterialAsync(string name, string newName, CancellationToken ct = default)
        => _blenderApi.Rna.SetAsync($"bpy.data.materials[\"{name}\"].name", newName, ct);
}

Shared value and reference types are documented in Types.