Thanks for the test project. I've checked the code and it seems that the transform is being applied as expected.
If I remove the line [Needle.RenderTransform = tform;] from aTestControl.xaml.cs, then the element keeps the default Identity transform and the needle is rendered differently.
See attached images.

NeedleIdentity.png (626 bytes)   

NeedleIdentity.png (626 bytes)   

NeedleTransformed.png (2,383 bytes)   

NeedleTransformed.png (2,383 bytes)   

If you enable line 52: Needle.SetValue(FrameworkElement.RenderTransformProperty, tform);
the needle should render in an angle. And it isn't for me. Are you seeing a different behaviour after uncommenting line 52?

This is not working either. Still no angled needle when setting tform directly to RenderTransform.

image-2.png (13,092 bytes)   

image-2.png (13,092 bytes)   

Oh sorry, I did the tests with the project configured to use WPF... now I see what is happening.
This is clearly a bug in Noesis, the default MatrixTransform (Identity) returned does not clone correctly.
We will fix it.

Thank you!