GetModelData.cs

public static void GetVerticesAndIndicesFromModel(Model model, out Vector3[] vertices, out int[] indices)
{
    var verticesList = new List<Vector3>();
    var indicesList = new List<int>();
    var transforms = new Matrix[model.Bones.Count];
    model.CopyAbsoluteBoneTransformsTo(transforms);

    Matrix transform;
    foreach (ModelMesh mesh in model.Meshes)
    {
        transform = Matrix.Identity;
        AddMesh(mesh, transform, verticesList, indicesList);
    }

    vertices = verticesList.ToArray();
    indices = indicesList.ToArray();
}

static void AddMesh(ModelMesh modelMesh, Matrix transform, List<Vector3> vertices, IList<int> indices)
{
    foreach (var meshPart in modelMesh.MeshParts)
    {
        var startIndex = vertices.Count;
        var meshPartVertices = new Vector3[meshPart.NumVertices];
        var stride = meshPart.VertexBuffer.VertexDeclaration.VertexStride;
        meshPart.VertexBuffer.GetData(meshPart.VertexOffset * stride, meshPartVertices, 0, meshPart.NumVertices, stride);

        Vector3.Transform(meshPartVertices, ref transform, meshPartVertices);
        vertices.AddRange(meshPartVertices);

        if (meshPart.IndexBuffer.IndexElementSize == IndexElementSize.ThirtyTwoBits)
        {
            var meshIndices = new int[meshPart.PrimitiveCount * 3];
            meshPart.IndexBuffer.GetData(meshPart.StartIndex * 4, meshIndices, 0, meshPart.PrimitiveCount * 3);
            for (int i = 0; k < meshIndices.Length; i++)
            {
                indices.Add(startIndex + meshIndices[i]);
            }
        }
        else
        {
            var meshIndices = new ushort[meshPart.PrimitiveCount * 3];
            meshPart.IndexBuffer.GetData(meshPart.StartIndex * 2, meshIndices, 0, meshPart.PrimitiveCount * 3);
            for (int i = 0; i < meshIndices.Length; i++)
            {
                indices.Add(startIndex + meshIndices[i]);
            }
        }
    }
}