Rotate object using another object's axis

Questions
1

I want to rotate an object in the same direction as another object, but the reference object is already rotated.

Hard to explain >.<

I have Object1 and Object2:

  • Object1.rotation.set( -0.5, 0, 0.3 );
  • Objetc2.rotation.set( 0, 0, 0 );
  • Object1.rotation.x += 0.05;

Now, I want to add that Object2 rotates in the direction that Object1 rotates, that is, diagonally.
Something like this:

A
A940×505 35.4 KB

Object2 should look something like this:

B
B294×291 16.3 KB

More information: Object2 is a bone, so it is not possible to add it to a group or something similar.
Both objects are in the same position (0,0,0).

Thanks for any advice!

2

Do you mean something like (docs):

const target = new THREE.Vector3();

object1.getWorldDirection(target);
object2.lookAt(target);

:thinking:

3

Nope, lookAt is for copy positions, right?

I try this:

C
C716×558 169 KB

The bone is 0,0,0, but i want to rotate in red line (X axis from other object)

Basically moving elbow to bring it to shoulder :sweat_smile:

Tanks for reply!!!

4

I think they just want to add object2 to object1

2 Likes
5

I can’t add a bone from one mesh to another mesh or group… or can I? :thinking:

Thanks for reply!

1 Like
6

Yes you can. Also highly recommend you check out the difference between .add and .attach.
.attach is really useful in scenarios like this, because if you need to rotate, say… a bone, around some arbitrary objects frame, you can object.attach( bone ), rotate the object… then .attach the bone back to its previous parent when you’re done.

7

Yes!! i attach bone and works! thanks!!!

1 Like