-
Swinging Sign:: Any Tuts or Suggestions?
In my Comp, I have a sign hanging from the ceiling from two cables. The sign and cables are all separate elements (3 different layers).
I want to have the sign swing back and forth, with the pivot points being the cables mounting point in the ceiling.
I have a general idea of what to do. I need to associate the POSITION of the sign to the ROTATION of the cables; correct?
How, exactly, do I do that in AE?
In Maya, there is Mel scripting where basically SignShape YTranslate = CableShape YRotateThat is a little rought, but I get the concept. Is there an easy way to do this in AE? Maybe by using tracking?
Thanks
-
16 Replies
-
its MUCH easier than you think. Unless you have some previous parent structure preventing you from being able to do this…you can just parent the sign to one of the cables. Or what i would do is parent all 3 objects to a Null and animate the null.
-
I don’t think that would work. I tried that. the problem is, when you rotate the parent (cable) , it rotates the child (sign).
With a cable suspended object, what happens is; the base of the cable swivels, which causes the cable to rotate from the pivot point on the ceiling. This causes the sign to actually move (on two axis- up and over), not rotate.
See, the sign it’s self doesn’t rotate. The position of the sign varies based on the attached cable on the sign, based on the pivot point of the cable.
Also, if I parent one cable to another cable, the child cable is no longer pivoting from it’s anchor (the ceiling).
I’ve found tracking to be a VERY EASY solution to my issue. I had to add a tiny blue dot on the end of my cable, and pre-compose my animated cable layer; but it’s working pretty well so far.
What I would like to know is, lets say there is complex key framing of cable-01. How do I tell cable-02 to do the same motion without key frames?
How can I write an expression that says: When cable-01 rotates 20*, cable-02 rotates 20*?
-
I’ve been thinking about this a little more while the tracker is analyzing…
I suppose I could’ve parented the sign to cable-01 and then just keyframes the rotation of the sign so it always appears parallel to the ground…
That is pretty simple, but it is extra keyframes.
That still leaves the problem with cable-02 tho. I guess I could have just copy and pasted the keyframes from cable-01, but again, extra keyframes…This is a simple exercise, I guess I was just thinking ahead to a more complex comp where it would be handy to have these elements relationships automated…
-
well for one you can copy and paste keyframes…but you can just alt+click the animated property, then youll get an expression pickwhip, and just pickwhip it to the one you want it to mimmic. This could have also worked with the sign, i thought you were having the sign swing front to back, in which case it would rotate a little in recoil depending on how much the cables swing. But if the cables sway side to side your right there would be no rotation…in which case you can use the method i just showed to put this on the signs x position (or depending on orientation whatever “side to side” axis is).
x = (thisComp.layer(“cables”).transform.zRotation)*-1;
value + [x,0,0]
-
if you wanted to do the parenting sign to animated cables and wanted to keep sign parallel, so your rotating on Z, alt click on signs z and pickwhip it to cables Z, and on the end of the signs script put *-1 and that should cancel the rotation out.
-
very helpful… this is what I was looking for.
So the pickwhip allows you to connect certain values of one layer to certain values of another layer/or the same layer?
and -1 always cancels out that value?
I appreciate the help, and yes, if I wanted the sign to swing front to back, parenting would have worked fine.
-
glad to help, the pickwhip doesnt necessarily “connect” them. When your writting expressions your usually retrieving a value or really just numbers with the pickwhip. So its more just using the information as a reference and you decide what to do with that information, and ya in alot of cases it is to seemingly “connect” them.
And *-1 just takes that information it got from the other layers rotation, and multiplied that number times negative 1, basically making it rotate in the opposite way of its parent, making it look like its doing nothing.
When it comes down to it its all just a bunch of numbers and how you can manipulate them.
-
I’d have built the sign and cables in their own 3d comp. This would have allowed you to add some inertia and reaction to the sign, lag and follow physics simulations.
bogiesan
This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”
-
I like where you are going with that, but it sounds like some more complex scripting would be involved…
I think I am a pretty fair animator and for this type of animation, I could pull it off with out physics…
I would like to learn how to do this in AE just for more complex comps tho. Can you give just a little more detail on how difficult this is in AE? I could do it in Maya, but it’s overkill for some projects.
PS. This is in it’s own 3d comp, just for flexibility if nothing else.
-
[Nick Pitcavage] “I like where you are going with that, but it sounds like some more complex scripting would be involved…
“Not at all. You _can_ create an expression that links the movement of the chains to the far end of the sign but, since the sign/chains are in their own precomp, you can easily add rotation to the sign (in the sign precomp) that syncs with movement of the chains in the main comp. You can do that just by adding those keyframes to the sign after you’re happy with the movement of the chains.
I do not understand 3D apps any more than I understand spreadsheet apps. Because I’ve been using AE since it was CoSA, I see precomposing workflows in my sleep. I still don’t get AE’s 3D but I stumble through it.
bogiesan
This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”
Reply to this Discussion! Login or Sign Up