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  • 5 months ago
In Blender 3D, Constraints are rules or restrictions you can apply to objects, bones, or cameras that control how they behave, move, or rotate—often automatically—based on another object, bone, or some condition.

Think of constraints as instructions that tell Blender: “Do this automatically whenever X happens.”

🔹 Key Points About Constraints

Control Without Manual Keyframes

You can make objects follow, track, or copy other objects automatically.

Reduces manual animation work.

Applied to:

Objects (like meshes, empties, cameras)

Bones (in rigs)

Cameras and lights

Not Deforming:

Constraints don’t change the mesh shape directly (use modifiers or rigging for that).

They only control movement, rotation, scaling, or visibility.

🔹 Common Types of Constraints

Copy Location / Rotation / Scale

Makes one object copy another’s position, rotation, or size.

Track To / Locked Track

Makes an object or bone always point at another object.

Often used for cameras or eyes.

Limit Location / Rotation / Scale

Restricts movement, rotation, or size within certain ranges.

Child Of

Makes an object behave like a child of another object temporarily or partially.

IK (Inverse Kinematics)

Used in rigging: automatically calculates bone rotations to reach a target.

Follow Path

Makes an object follow a curve or path.

Great for cars, cameras, or flying objects

Category

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Learning
Transcript
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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