HelixViewerPanel.xaml

<UserControl x:Class="QuickLook.Plugin.HelixViewer.HelixViewerPanel"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:helix="clr-namespace:HelixToolkit.Wpf;assembly=HelixToolkit.Wpf"
             mc:Ignorable="d" 
             d:DesignHeight="800" d:DesignWidth="800">
    <Grid>
        <helix:HelixViewport3D 
            x:Name="view1"  
            ZoomExtentsWhenLoaded="true" 
            ZoomAroundMouseDownPoint="True" 
            ShowViewCube="False" 
            CameraRotationMode="Turnball"
            >
            <ModelVisual3D x:Name="PreviewModel">
            </ModelVisual3D>
            <!--<helix:MeshGeometryVisual3D x:Name="PMXGeometryVisual3D"  />-->
            <helix:DefaultLights />
            <helix:HelixViewport3D.RotateGesture>
                <MouseGesture MouseAction="LeftClick"/>
            </helix:HelixViewport3D.RotateGesture>
        </helix:HelixViewport3D>

    </Grid>
</UserControl>