http://blogs.msdn.com/wpf3d/archive/tags/D3DImage/default.aspxTags: D3DImageen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/wpf3d/archive/2009/01/13/d3dimage-and-software-rendering.aspxWed, 14 Jan 2009 05:17:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:9317841wpf3d2http://blogs.msdn.com/wpf3d/comments/9317841.aspxhttp://blogs.msdn.com/wpf3d/commentrss.aspx?PostID=9317841<p>If the WPF render thread is doing software rendering, <a href="http://msdn.microsoft.com/en-us/library/system.windows.interop.d3dimage.aspx" mce_href="http://msdn.microsoft.com/en-us/library/system.windows.interop.d3dimage.aspx">D3DImage </a>will not show up. I don't think we specifically called this out in the documentation so it can come as a surprise when you first encounter it. Off the top of my head, here are times when the render thread is in software:</p><ol><li><a href="http://msdn.microsoft.com/en-us/library/system.windows.media.rendercapability.tier.aspx" mce_href="http://msdn.microsoft.com/en-us/library/system.windows.media.rendercapability.tier.aspx">RenderCapability.Tier</a> == 0</li><li>You set <a href="http://msdn.microsoft.com/en-us/library/system.windows.interop.hwndtarget.rendermode.aspx" mce_href="http://msdn.microsoft.com/en-us/library/system.windows.interop.hwndtarget.rendermode.aspx">HwndTarget.RenderMode</a> = SoftwareOnly</li><li>A video card driver <a href="http://msdn.microsoft.com/en-us/library/ms742196.aspx#other_resources" mce_href="http://msdn.microsoft.com/en-us/library/ms742196.aspx#other_resources">before November 2004</a> (date subject to change in the future)<br></li><li>Remote desktop</li><li>The window size is larger than the max texture size of the video card (rare)<br></li></ol><p>All of these cases should be covered by simply checking #1 except for #2. You might be surprised by #4, but in 3.5 SP1 we had to change how remoting works. </p><p>You're probably thinking that I left out <a href="http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.rendertargetbitmap.aspx" mce_href="http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.rendertargetbitmap.aspx">RenderTargetBitmap</a> and printing since they both use software rendering, but they happen on the UI thread! D3DImage will show up because they call <a href="http://msdn.microsoft.com/en-us/library/system.windows.interop.d3dimage.copybackbuffer.aspx" mce_href="http://msdn.microsoft.com/en-us/library/system.windows.interop.d3dimage.copybackbuffer.aspx">CopyBackBuffer()</a>.</p><p>-- Jordan</p><p>P.S. Don't forget to read the <a href="http://msdn.microsoft.com/en-us/library/cc656910.aspx" mce_href="http://msdn.microsoft.com/en-us/library/cc656910.aspx">perf notes</a> when using D3DImage <br></p><img src="http://blogs.msdn.com/aggbug.aspx?PostID=9317841" width="1" height="1">3DWPF3.5 SP1D3DImage