Hi,
I was having a hard time understanding why the “move center to pivot” button did not seem to work. After some tests and brainstorming, it all became clear. I put my conclusions in the linked video, please tell me if it seems correct and what do you think. Cheers.



Gz

Move Center to Pivot is working as expected, because moving an object center does not involve “carrying with it the shpere's points”.
It's very similar to XSI's “center mode” (button near the point, edge, etc in the upper right selection tab) in which you can freely transform an object center while having the geometry stay in place. This is the opposite of moving the geometry (at SOP lvl in Houdini's case) while keeping the center in place.

edit
just to be clearer: the Houdini's centroid is not the geometry's bounding-box center, like COG in XSI, which is a viewport manipulation crutch (and a very useful at that) that will snap the gizmo at the center of the geo's b-box upon toggle on.
Also, “nothing happened” at 0:34 is not exactly accurate - a transform node has been created at SOP lvl.

one thing is true, the name Move Center To Pivot is confusing especially right next to Move Pivot To Center
as:

Move Pivot To Center - literally changes values of Pivot parameter to align it with the geometry bbox center

BUT

Move Center To Pivot - suddenly by Pivot doesn't refer to Pivot parameter, but rather origin of the object's local space and therefore moves geometry so that the center of the bounding box aligns with that origin regardless of the Pivot parameter values, so the actual pivot may still be offset from the geo center if Pivot parameter is not 0,0,0

Hi guys

Thanks for the answer. I am trying to clarify things but sometimes it gets even more confusing. So in order to know what we’re talking about, I suggest we define some terms:

- Centroid : the center of the bounding box of the points, not the average position of the points. This is from the Hou documentation.
- Center : according to what I’ve understood, it’s the same as the centroid.
- Pivot : All transformations are relative to an object’s pivot point. An object scales toward/away from the pivot point and rotates around the pivot point. So according to the doc, it is a handle for the transforms.
- Origin : according to the doc, it is the same as the pivot.
- Geometry bounding box center : you guys are mentioning this in your post, is it different from the centroid and the pivot? Or are you just speaking about the centroid/center?
- Origin of the object's local space: Tamte, you mentioned this in his post, what would be the definition of this term? Would it be the same as the “pivot without its offset”?

As for XSI’s “center mode”, I have not found the Houdini equivalent. In XSI you can move the center while the points stay in place, but in Houdini, if you move the points, the center follows, and if you move the center, the points follow. Check the attached picture I did.

Yes, move center to pivot create a transform node at SOP level but this node does not give any information, every scale rotate translate is at 1 0 0, there is no visible offset.

If I rephrase what Tamte said : “Move Center To Pivot leads the Geometry bounding box center to align with the origin of the object's local space”.
If the “Geometry bounding box center” is the centroid/center. And if the “origin of the object's local space” is the pivot without its offset, then it is the same explanation as in my video.

Correct me if I'm wrong

I know this thread is four years old... but I'm struggling to get my head around the same issues - made considerably worse by seemingly loose language / definitions in both the menus and Houdini documentation.

Can anyone - Sidefx staff preferably - provide a definitive answer to these questions?