EyeonTips:Manual/Fusion 6/Text 3D
From VFXPedia
Character Level Styling
The Text 3D tool doesn't support Character Level Styling directly. You have to create a Text+ tool first and modify its text field with a character level styling modifier. Then either connect the Text 3D's text field to the modifier that is now available or copy the Text+ tool and paste its settings to the Text 3D tool (right-click -> paste settings).
Uncapped 3D Text
To hide the front face of extruded text, uncheck "Use One Material" on the Shading tab and reduce the 1st material's color to black including its alpha value.
-- mentioned by Jeff Krebs on the Laffey list