The message implies that there is no variable <t> in the expression,
which would also explain why it's not rotating.
In my mathmap package, Rotate is:
filter geom_rotate (image in, float angle: 0-6.283)
in(ra + ra:[0, angle])
If you want to pick a specific rotation, make sure you have
updated the preview, then click the User Values tab and change it.
If you want an animated rotation, then you need an expression
such as this, where t animates from 0.0 to 1.0, resulting in a
2*pi rad (360 degree) rotation:
filter geom_rotate_animated (image in)
in(ra + ra:[0, t*2*pi])
-- Tom Rathborne ------------------------------- Itinerant Theory Generalist --
You got to make the back of the fence that nobody will see
just as good looking as the front of the fence.
That will show that you're dedicated to making something perfect.
-- Steve Jobs