Rotation Centre Confusion

[razorpig]

Hi,

I'm sure there's a very good explanation for this and I'm just not getting it, but I would really appreciate a simple explanation of how all these different transform origins interact and relate to one another.

Hopefully this short video will explain everything much better than I can.

I'm totally confused.....please can someone guide me to that eureka moment because rotating a square on a blank canvas shouldn't be this confusing.

[Aammppaa]

My understanding is…

1) The rotation lollipop always rotates around the bounding box center. As do the corner rotation handles, unless you hold down the modifier (right mouse on Windows), in which case the rotation is about the opposite corner.

2) The 3x3 transform array in the Transform panel affect entries in the Transform panel only. Note you can click the 3x3 array a second time as a convenient way to Show Transform Origin.

3) The Transform Origin is not linked to the 3x3 Array. I guess it shows in bottom left (in you video) because you dragged it there at some point? Its location is remembered per shape. Double click the Transform Origin to reset it to the center or drag it somewhere else.

 

[razorpig]

@Aammppaa Many thanks for your reply. I'm beginning to understand the source of my confusion.

So the 3 x 3 array in the Transform panel actually has absolutely nothing to do with the Transform Origin accessed via the context toolbar, even though clicking on the 3 x 3 array a second time will make the latter visible and activate it on the toolbar? No wonder I'm confused !

A slight correction to your first point - it appears the lollipop and corner rotation handles do indeed always rotate around the centre of the bounding box unless the Transform Origin is enabled, in which case they will rotate around that ( I couldn't get the right mouse modifier thing to work but that's not too important ).

Referencing your third point - I purposely moved the transform origin to the bottom left just for demonstration purposes.

I think the crossover of terminology is the root of all the confusion - when we click on any of the 9 points in the 3 x 3 array in the Transform panel, what are we setting if not the Transform Origin ? And yet this has nothing to do with the Enable Transform Origin button. A simple re-phrasing might help avoid a lot of confusion. 

Anyway - thank you again for your reply Aammppaa. You did indeed guide me to a better understanding, if not quite a eureka moment  Much appreciated.

 

[R C-R]

23 hours ago, razorpig said:

I think the crossover of terminology is the root of all the confusion - when we click on any of the 9 points in the 3 x 3 array in the Transform panel, what are we setting if not the Transform Origin ?

When active, the 9 anchor points in the Transform panel set the origin for transformations done in the Transform panel. Note that the values for X & Y change depending on which one is selected, which is to be expected because they indicate the origin for rotations, height & width changes, etc.

[razorpig]

Thanks R C-R. After some experimentation and with help from this forum I now fully understand how it works. However, I can't help feeling it would be far more intuitive if there was at least some correlation between the Transform Panel and transforming objects on canvas. As mentioned previously, we seem to have two entirely independent Transform Origins and yet one of them is activated by clicking ( a second time ) over the area intended for the other.

[R C-R]

1 hour ago, razorpig said:

However, I can't help feeling it would be far more intuitive if there was at least some correlation between the Transform Panel and transforming objects on canvas.

There is some correlation, although perhaps it is not as obvious as it could be: if the transform origin is enabled on the canvas (IOW, the target icon is visible), transformations using either the Transform panel or the Move Tool will use it as the transform origin. If it is not enabled, the Transform panel uses one of the 9 anchor points for that while on the canvas the Move Tool does not.

That is why that for example, if you move the origin away from the center of the object, toggling it on & off changes the X & Y values in the Transform panel.