Make 2D object rotation look like 3D

Question

First of all, sorry for that title. I really couldn't find something better, how to describe my problem in short.

I've drew a lock, you can see it on image:

I would need to create a frame animation, so the lock will end like this:

So the final animation will be similar like this one: dribbble.com/shots/1141621-Lock-Icon-Animation-GIF

Here's my problem: I cannot draw the "bend" on the top of the lock (the U shape). If I distort it in PS, it's just like a paper, it flips, and there's no thickness of the metal "U". And when it comes to drawing, I don't know the angle in which I have to "bend" the "U" shape correctly, so I can't even do it by hand.

How could I draw it, so the final animation would look like the one I've described?

Thanks.

Answer 1

Ok, i did this image for fun. Though I used Illustrator, because it felt more handy fr the task at hand (not perfect mind you). Since there is a limited amount of frames. The result can be seen below:

Image 1: after 9 copies and one mirror about the dashed line

This is the process.

1. Draw the initial shape. I suggest using a grid as we need to align the shapes later.

2. apply a effect 3d rotate effect on your shape set values to 0 0 0

3. copy shape. then increment the z axis by say 10 degrees. copy again increment until you have done a 90 degree turn. Note the 90 degree shape has to be hand drawn.

4. Swap stroke and fill, then expand the shapes. (otherwise the flatness will become visible)

5. Ungroup all shapes and delete the bounding box.

6. Swap stroke and fill again

7. align items on one spot then distrubute them side by side.

8. mirror about the mirror plane for the next 90 degrees.

all in all it takes about 7-10 minutes to do, yeah there is a faster way to do this but its easy enough to do manually. To export the sequence see this post

If you dont have illustrator you can instead of rotation use a 100*cos(angle) as scaling factor per frame on a path and then stroke later.