Anchor Point vs. Position

Hi Everyone,

I’ve seen a few recent tutorials that suggest using anchor point instead of position key frames to move video and stills around in AE and Premiere. Can someone explain why one using anchor point is better than position? I have the CS5.5 version, and I’m just curious about the difference/benefit.

Thanks in advance,
Donovan

回答1

the anchor point is relative to the layer (with 0,0 being the upper left corner of the layer), position is the relationship between a layer’s anchor point and the comp.

if the layer is the same size as the comp, the default values for each would be the same, however if you have a layer that is not the same size as the comp, then you’ll see a difference — like

if you created a new solid that was 100×100, the anchor point would be 50,50, but the position would be the center of the comp (i am assuming the comp is not 100×100).

the anchor point is also the ‘center’ of the layer for properties like rotation and scale, so if the anchor point is say 0,0 the scale and rotation properties will react diffferently that if it is in the center of the layer.

see more here:

https://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103906c6dea-7dada.html

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

Thanks Kevin, that helps. I’ll check out the link you included. I think it will make more sense after I try moving things around in AE. Have a good day, Donovan

回答2

In general, animating position is more intuitive — you grab the layer, move it around, a keyframe关键帧 is set, etc.

For Anchor point you often drag the numbers around in the timeline, or you can use the ‘Y’ tool (I forget its name, the Y key is the shortcut) and hold down Cmd/Ctrl while dragging the anchor point and the layer will move.

The key here is that the anchor point remains in the center of the composition.

This means that rotations will happen around the center of the composition,

and scaling will happen around the center of the composition.

The visual result of all this is it looks more like a camera was panning摇摄, rolling原地转圈, and zooming, instead of the layer itself. So for stuff like maps and photos, where you want to make it seem like the camera’s in charge, anchor-point animation is almost always better….

Ben, clears it up for me. I understand now, these forums are great!

Thanks very much,
Donovan

原文地址：http://www.cnblogs.com/chucklu/p/16861859.html