Replacing w/

<TransformGroup>
<TranslateTransform X="-3" Y="12"/>
<RotateTransform Angle="270" />
</TransformGroup>

but would appreciate some commentary on breaking change.

CompositeTransform is a NoesisGUI extension, so it should include the NoesisGUIExtensions namespace:

<Grid

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

xmlns:noesis="clr-namespace:NoesisGUIExtensions;assembly=Noesis.GUI.Extensions">

<Rectangle Fill="Red" Width="400" Height="200">

<Rectangle.RenderTransform>

<noesis:CompositeTransform Rotation="40"/>

</Rectangle.RenderTransform>

</Rectangle>

</Grid>

Understood, thank Sergio. Is this a change or did it somehow magically work before? I'm OK with change.

In 2.2 version that class was incorrectly registered without the namespace, so it couldn't be used in Blend and our extensions nuget.
We fixed that for 3.0 version.

One of the few things missing to have final 3.0 is a document about 3D in Noesis. We are on in.