three.js - how do I rotate a cylinder around a specific point?

Question

I've referred following questions for object rotation.

• link 1 link 2 link 3 link 4 link 5

But could not understand exactly how do I rotate a cylinder around a specific point ?

Answer 1

I am assuming that what you mean is that you want an object to rotate around a specific point within it's geometry.

For example, the cylinderGeometry rotates around it's center. Suppose you want it to rotate around its end.

What you need to do is translate the cylinder geometry right after it is created so that the desired point within the geometry is now at the origin.

geometry.applyMatrix( new THREE.Matrix4().makeTranslation( 0, cylinderHeight/2, 0 ) );

EDIT: You can now do this, instead:

geometry.translate( 0, cylinderHeight/2, 0 ); // three.js r.72

Now, when you rotate the cylinder, it will now rotate around its end, rather than its middle.

The end that it is rotating around will also be located at the position you have set for the cylinder mesh.

Obviously, you can do this with any geometry, not just cylinders.