Re: Circling objects effect "Youtube look" by Paul Hennell on Jan 18, 2009 at 5:16:44 pm
As a student still learning AE, the rotating part seemed like quite an interesting challenge so I've had a bit of a fiddle. I've found two successful ways to achieve the effect - I can't guarantee either of these is the most sensible or the most effective way to achieve this - but they work which is enough for me.
Both methods require your items as 3d layers plus a Null object (also 3d).
First (simpler(?)) method is - arrange your items in a circle around the Null. Parent the items to the null then either Auto-orient your items towards the camera (Add a camera too) or use an expression to subtract the nulls rotation from the items rotation. (items Y Rotation = - thisComp.layer("Null 2").transform.yRotation).
This works fine but you have to manually arrange your items into the circle, which is annoying, uneven and hard to edit if you want to make it bigger or add more items. In an effort to solve such problems I've worked out an expression led solution as follows -
Name your Null object 'Controls' and add two expression sliders called "Radius" & "Number of Items" and an angle control called "Rotation".
In the position property of your items add the following expression:
radius = thisComp.layer("Controls").effect("Radius")("Slider");
angle = degreesToRadians(thisComp.layer("Controls").effect("Rotation")("Angle"));
offset = degreesToRadians(index * (360/thisComp.layer("Controls").effect("Number of Items")("Slider")))
x = thisComp.layer("Controls").transform.position - (radius* Math.sin(angle - offset));
z = thisComp.layer("Controls").transform.position + (radius* Math.cos(angle - offset));
y = thisComp.layer("Controls").transform.position;
This will orbit your items around the position of the controls null, in a circle sized by the radius slider. Set the Number of items control to whatever number of items you have (Don't set it to 0, it'll break) and it will position them all equally about the circle. Key frame the rotation control to make it spin.
Hopefully that all made sense - if you're interested in the expression it mostly a re-working from reading this. If anyone has a better method I'd love to see it.
Only in after effects do children get to pick and whip their parents.
Re: Circling objects effect "Youtube look" by Ariel Brener on Jan 18, 2009 at 8:03:18 pm
Wow! guys you are amazing!
craig hellen: thanks for the reflection tutorial - I know this Andrew Kramer's tutorial - but still thanks for your suggestion.
you are a life saver! this expression rocks!
It's working great!
I'm thinking about adding a scale slider to your great expression!
BTW do I have to parent the objects to the controls Null? - because It worked without parenting.
But still if you look at the the first sample I up loaded you'll see that the scale ratio between the foreground & background objects is big.
I'm trying to get that effect by playing with camera lenses and decorating with depth of field.
Is there a better way to control the scale ratio?
Also I want the background objects to be higher so I can see them.
this also I think I can get by changing the camera view.
but when I play with the camera POV the objects prespective change accordingly - Can I some how go around that (like in the sample above?)
You really saved me! I was really stuck!
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