
I used '3dtools.dll' and it was right wrok in 'expression Blend4'.
add reference
Like this:
xmlns:tools="clr-namespace:_3DTools;assembly=3DTools"}
.
.
<tools:TrackballDecorator>
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</tools:TrackballDecorator>
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<tools:TrackballDecorator>
but it does not work in 'MS Blend for Visual Studio(...