spin tool VS screw modifier (animated cylinder opening)

Dear all,
I’d like to animate a cylinder like “opening to view its interior”.
let’s say from 360° to 180°, kind of animated cross section.
I can animate the screw modifier angle, but the “front” face are not visible.
with the spin tool the front faces are displayed but can’t be animated.
Any idea how to animate the angle with spin tool or filling the faces with screw modifier
Thank you.


spin_screw_animation.blend (541 KB)

Why not use Array modifier on curve?

Ridix’ answer will work, but this might be easier to set up than a curve:


It’s just an altered cube that’s being modified by a circular array.
The Array Modifier is set to Object Offset and targeted at the Empty. Since the Empty is rotated 15° along Z it makes the array in 15° increments.
For a smoother animation you’ll need finer increments - and more so the more frames your animation takes to complete.


If you need this animation to be very smooth there is also a way to do this entirely with curves - a path curve (circular), a bevel curve (square), and a taper curve (animated), but the shading on the caps ends up looking pinched in my experience.


Actually, after considering this a little more, I think the best approach is to use a Curve Modifier, then use Shape Keys to control the scale. You may have to play around a bit to get the axes oriented correctly, but this method produces the best looking results. It will animate smoothly and with no shading issues.



Dear All,
A Big thank you to Ridix and Quantum Anomaly for taking time.
Quantum Anomaly solution works like a charm:eyebrowlift:.
Best Regards to both of you

Sorry for resuscitating this old thread, but I’m interested in knowing more details about how to achieve the last two methods that you explain here (those that do not contain Array modifier). If it’s not too much trouble, sharing .blend file. It does not matter if it does not have a square section, it can be a circle with a cap.