00:00In the previous video, we have seen how a child object or a child bone behave when
00:10parented to another object. It inherits the transformation of the parent, but its transform
00:17channels are kept clear, meaning that in its local space, it's not transformed.
00:24The other way to transform an object using another object is Constraints. With Constraints,
00:31we can copy the location, the location, the scale, or use any other mechanism to create
00:39a motion or transformation on an object. To illustrate this, we'll be using pre-primitive,
00:45a sphere, a cube, and a cone. We'll parent the cube to the sphere so that it will follow
00:51the sphere transformation. With the cube selected, we'll go into the Properties panel, go to
00:57the Constraint and add a copy location. For the moment, the constraint is red because
01:03it doesn't work, because the cube needs a target to be constrained to. We'll target the cone.
01:10As we did, the cube moved to copy the position of the cone, so it got offset and is now sharing
01:18its location with the one from the cone. If I move its parent, it won't be translating,
01:24but it will still inherit the rotation and the scaling from its parent. Let's get rid of
01:30the constraint by closing it, and now let's add the same constraint to the cone targeting
01:37the cube, meaning that the cone will now copy the location of the cube. Since it's copying
01:44the location of the cube in world space, whenever the cube is moving, and whatever position
01:51it adds in the world space, the cone will follow. Since the constraint only affects location,
01:59scaling or rotating the cube won't modify the rotation and scaling of the cone. When we are
02:05using world space to world space, whatever the position of the cube or the target is in
02:13world, whatever the hierarchy you have in your rig or in your parenting chain, the constraint
02:20object will go to this position for sure. While parenting is absolute, constraints can be dialed
02:28and have an influence that will allow us to reduce or increase their influence from 0 to 1. If we now switch
02:36to local space, using local space as an input and local space as an output, meaning that the cube
02:45local space will influence the cone local space, we can see that if we move the cube using the
02:52parent, nothing happens. Because as explained before, whenever you move a parent, the child will move
02:59in the world space, but its local space won't be transformed. Since we are using the local
03:06space of the cube to transform the local space of the cone, we need to record transformation
03:14directly onto the cube, not through its parenting chain. If I now move the cube on its local
03:22Z axis by pressing G and Z two times, you can see that now the cone is also moving on its local
03:31Z axis. Since both don't have the same orientation, they are moving in separate axis world space-wise.
03:39acho-wise
03:40!!!!
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