What Does Rotation and Scale Do?

When you press Ctrl and A it pulls up the Apply menu; what does Rotation and Scale do?


When you move, rotate, or scale an object you aren’t really editing it. You’re just changing where it’s at or how big it displays. When you apply those translations it actually changes the data of the object. A 1x1 cube can be scaled x2 and still in local space it is a 1x1 cube. By applying the translation it causes the object data to change so that local space = world space.

Make a cube and rotate it a bit. Then go into edit mode and you’ll find that as long as you’re working in local space the axis still follows the original orientation of the cube. When you apply the rotation that original local space orientation is lost and the axis will be relative to world space.

Applying rotation makes the current object orientation to be aligned with global axes. If you rotate a plane in object mode so that it’s facing the front view (plus or minus 90° along global X) and then apply that rotation, that is the new orientation, it’s local rotation is 0 on all axes.
If you were to rotate it and then clear the rotation (alt+R), it would zero out the rotations and it would go back where you started.

Applying scale converts the visual scale (scale in object mode) to actual dimensions used in edit mode and then reset the object scale back to 1,1,1. For mesh object it would mean that edge lengths in edit mode correspond to what you see in object mode. That is important for many tools and modifiers to behave like you would expect.

Ctrl+A -> rotation & scale is just a convenience function to apply both.

Fascinating! Thanks guys.