-
Creating an unfurling spiral path
Hi
Just a warning in advance that this is a long post, and probably is only of interest to someone who like solving difficult problems for the fun of it.
I’ve been trying to create an unfurling spiral path, like an unrolling carpet seen from the side. I thought it could create a new way of animating foliage or flourishes and perhaps unlock possibilities in 3D stroke. I wanted to avoid using C4D or similar, although that probably is the best way.
Anyway, I couldn’t find a way to do it, so in the end I did it manually.
I’ve attached a link the the project below. My results were almost good enough (in my opinion) but I ran into a few problems.1. I had thought that I would create the whole thing with linear keyframes and them pre-comp my results in order to use time remapping to apply easing and change the speed. However, time remapping produced glitches that look like previous states of the path before I ironed out the kinks. It appears that After Effects remembers the path shape at a sub-keyframe level, and so as the keyframes are squashed and stretched during time remapping, intermediate states become visible.
To get around this I could stretch my animation by holding alt and dragging the keyframes out in order to reveal all the intermediate states. I could then correct and keyframe those individually. As time-consuming as this might be, hopefully I could reduce the likelihood of glitches. However…
2. …the other problem is that what I have done is extremely inflexible. It will only work with a spiral of the dimensions and angle that I have chosen.
During the process I wondered if the process could be automated.
If you create a spiral in Illustrator, a new vertex is added each time the path direction curves 45 degrees. Illustrator also gives you the length of each section of the path between the vertices. By dividing the length of the path sections by the number of frames you wish the unfurling to cover, you can calculate where the spiral needs to rotate each 45 degree increment, and where each vertex needs to be as it hits the ‘ground’, or the plane along which it is unfurling. You can see in my project where I have used the ‘Colour Guide’ layer to determine this.As long as the spiral is not stretched, but is created in Illustrator holding the shift key, then 3 measurements should hopefully be enough to determine the size of the spiral and how tightly it is coiled:
(a) The length of the path.
(b) The distance between the bottom of the spiral (assuming that the outermost vertex is at the bottom) and the vertex at the top.
(c) The distance between the bottom / outermost vertex and the central / innermost vertex. These could actually be dialled in manually, since in AE you can use a shape layer to measure these distances. My hope is that these measurements would be accurate enough to enable a smooth end-product.So we have ways to determine the type of spiral in each case, and the bare bones of the animation that needs to be created. It’s all the intermediate stages that are the problem, and that’s why I am hoping that automation is the answer.
I’m aware that this probably seems a pointless endeavour and I won’t be too disappointed if no-one replies. I just thought it was an interesting problem. I should say that my knowledge of maths is very limited, so apologies if I have made it sound as if I think this would be simple to achieve. I imagine it would actually be very challenging.
Thank you
Ed
-
2 Replies
-
I’ve seen this tutorial a few days ago:
https://greyscalegorilla.com/tutorials/how-to-build-a-bone-and-joint-chain-in-cinema-4d/Is for c4d, but maybe you can get great ideas on how a spiral can be done and controled, specialy the golden proportion part. My first aproach would be try to setup a similar bone hierarchy with comps/nested comps or a layer name based hierarchy setup.
Hope it helps! -
Thanks Miguel, that sounds really interesting, I’ll have a look.
Reply to this Discussion! Login or Sign Up