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Activate/DeActivate A parent using a checkbox
Hi AE Expression Wizards! I’m looking for an expression to use a “checkbox” to activate and/or deactivate a parent. For example, I separated the X and Y positions on the Parent layer AND on the child layer. Then, I put a checkbox control on my child layer. And I wanted to add an expression on the X and/or the Y position to parent the child layer position to the parent layer position only when I check the checkbox. Otherwise, my child doesn’t follow the parent. Could you help me??? Thank You in advance.
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2 Replies
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See if this works – take note that it doesn’t account for keyframing the checkbox which will result in position jumping –
for xPosition –
if (effect(“Checkbox Control”)(“Checkbox”) == 1 || thisLayer.parent == null) {
// When checked or no parent, use normal/parented position value
value;
} else {
// When unchecked, counteract parent’s position
parentLayer = thisLayer.parent;
// Get parent’s world position at current time
parentWorldPos = parentLayer.toWorld([0,0]);
// Get parent’s world position at time 0 (initial position)
parentWorldPosT0 = parentLayer.toWorld([0,0], 0);
// Calculate parent’s position change
parentDeltaX = parentWorldPos[0] – parentWorldPosT0[0];
// Subtract parent’s movement from our current position
value – parentDeltaX;
}
for yPosition –
if (effect(“Checkbox Control”)(“Checkbox”) == 1 || thisLayer.parent == null) {
// When checked or no parent, use normal/parented position value
value;
} else {
// When unchecked, counteract parent’s position
parentLayer = thisLayer.parent;
parentWorldPos = parentLayer.toWorld([0,0]);
parentWorldPosT0 = parentLayer.toWorld([0,0], 0);
parentDeltaY = parentWorldPos[1] – parentWorldPosT0[1];
value – parentDeltaY;
}
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This may not be what you’re after, as it requires the checkbox to be keyframed to on when you want the child’s x position to follow changes in the parent’s x position:
p = thisComp.layer("parent").transform.xPosition;
cb = effect("Checkbox Control")("Checkbox");
accum = value-value;
if (cb.numKeys > 0){
n = 0;
n = cb.nearestKey(time).index;
if (cb.key(n).time > time) n--;
if (n > 1){
if (cb.key(n).value) accum += p - p.valueAtTime(cb.key(n).time);
for (i = n-1; i > 0; i--){
if (cb.key(i).value) accum += p.valueAtTime(cb.key(i+1).time) - p.valueAtTime(cb.key(i).time);
}
if (cb.key(1).value) accum += p.valueAtTime(cb.key(1).time) - p.valueAtTime(0);
}
}else{
if (cb.value) accum = p - p.valueAtTime(0);
}
value + accum
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