Child Center Moves on Parents Que

[Falam]

I have two objects, one is the child of the parent. When I set the center for the child and lock it, remove classical scaling from the child object then move the parent, the center for the child moves, is there any way to fix this ?

[Falam]

How can I set anything with the parameter connection editor, if the child object center is not where it should be relative to the parent and keeps moving it's self to 'center of verticies' driving me mad.

[Falam]

The Center is where I want it. De-select the object and select it again; after freezing transformations and setting a neutral pose and freezing the model.



WTF ?

[sonictk]

I'm not exactly sure what you're trying to do, but usually when it comes to pivots in XSI:

- is ChildCompensation on?
- Did you reset the pivot before setting neutral pose/freezing transforms/moving center to vertices?
- Did you freeze after performing a Center operation?

Also, is COG on? You might be looking at the wrong pivot...

[Falam]

I'm not exactly sure what you're trying to do, but usually when it comes to pivots in XSI:

- is ChildCompensation on?
- Did you reset the pivot before setting neutral pose/freezing transforms/moving center to vertices?
- Did you freeze after performing a Center operation?

Also, is COG on? You might be looking at the wrong pivot...

I got the center to stay where it should, on the positive note, I think I was doing the order to keep the center in it's new position wrong.

On the negative side of things, when I set the new center for the 'child' object which has a parent, when I move the parent the child doesn't move ? I re-parented the child to the parent after setting the childs new center, when I move the parent the child doesn't move.

[sonictk]

I'm not exactly sure what you're trying to do, but usually when it comes to pivots in XSI:

- is ChildCompensation on?
- Did you reset the pivot before setting neutral pose/freezing transforms/moving center to vertices?
- Did you freeze after performing a Center operation?

Also, is COG on? You might be looking at the wrong pivot...

I got the center to stay where it should, on the positive note, I think I was doing the order to keep the center in it's new position wrong.

On the negative side of things, when I set the new center for the 'child' object which has a parent, when I move the parent the child doesn't move ? I re-parented the child to the parent after setting the childs new center, when I move the parent the child doesn't move.

...Do you have child compensation on at this point...? I can't imagine any other scenario in which the parent would be able to move without the child following unless you have an expression defining its opposite translation...

Maybe if possible you could record a small video or more screenshots of what you're trying to achieve? I'm still not sure what your ultimate goal is here...

[sonictk]

(Got your PM)

Hi, I think it would be easier to understand what issues you're facing if you showed your whole UI, but I recorded a short video of how I have a simple parent-child relationship set up and how I would change the pivots for objects within that relationship:



Hopefully it makes more sense, though I suspect you probably have a different problem...check your operator stack to see if anything is affecting it? Especially for your scale, you might want to check your kinematics to see if it's being connected/locked to something else...

[Falam]

sonic - I sent you another video. The parent issue is solved, I had to re-parent, something I didn't do when it's late in the night

In regards to the center problem, in the video I set the center where I want it, by snapping the center to the corner of the object. Then I freeze the center, set Neutral pose, freeze translation, then I'll animate the scaling, the center will then move on it's own to the middle of the object, how do I fix that ?

[sonictk]

From your video, am I correct in guessing that you are trying to setup a sliding flexible panel? Normally I would actually rig a seperate NURBS curve/implicit object to act as the actual control shape for the mesh and setup an expression to control the scale of the panel...(if necessary, use bones too to control the compression of the geometry )

But of course, sometimes you just want it to work and to work NOW.

Anyway, I went ahead and recorded a short demo of how I would approach it if you were really short on time. Make sure you have 'Edit Obj pivot' enabled in the transform MCP; I think you might have it disabled.

[Falam]

Now it works, the problem was I didn't have, as you said 'edit object pivot' enabled.
Except the child object won't freeze in world space, I froze the model, I froze the object, I froze all transformations, the object is not frozen in world space ?

I'd like to see how you would do this setup using nurbs and expressions, if you don't mind ?

[sonictk]

Now it works, the problem was I didn't have, as you said 'edit object pivot' enabled.
Except the child object won't freeze in world space, I froze the model, I froze the object, I froze all transformations, the object is not frozen in world space ?

I'd like to see how you would do this setup using nurbs and expressions, if you don't mind ?

In world space, you won't see the object go to 0,0,0. It's normal; you won't be inheriting any any xforms (freezing xforms iirc basically parents the obj to the root/world, which is why you will see the xforms relative to the root node if you switch to world. This is the same for Maya as well.)

I'm currently in the middle of something (school finals for 2 weeks aww yea), but I'll see if I can do a quick vid demo later in the week. You don't have to use a NURBS curve, it's just what I use in Maya so I'm used to it. You would create a control obj and then connect that obj's translate property to the geometry's scale property either via the expression editor or the parameter connection editor. You can also drag-n-drop the scaleX from the sliding panel to translateX of the driving object as well. (It's easier to use parameter cxns I guess, I'm just so used to doing it the script kiddie's way now )

Take the time to read the XSI docs for writing expressions and parameter cxns, they're quite useful once you get the syntax.

[Falam]

@sonic - Thank you for the help I understand what you mean by setting things up by expressions etc If you can set up something, for the sake of it, I'd like to see, ya know

In world space, you won't see the object go to 0,0,0. It's normal; you won't be inheriting any any xforms (freezing xforms iirc basically parents the obj to the root/world, which is why you will see the xforms relative to the root node if you switch to world

What did you mean by iirc ?

[sonictk]

@sonic - Thank you for the help I understand what you mean by setting things up by expressions etc If you can set up something, for the sake of it, I'd like to see, ya know

In world space, you won't see the object go to 0,0,0. It's normal; you won't be inheriting any any xforms (freezing xforms iirc basically parents the obj to the root/world, which is why you will see the xforms relative to the root node if you switch to world

What did you mean by iirc ?

Hi, hey I added a little demo scene that you can go through and pick through. Main thing to look at is the expression on the mover/child so that you can get the mover to be at 0,0,0 and be at the initial position that you want for the sliding door. (I didn't do a maximum/minimum 0 - 1 setup on the control, I have to admit I haven't played around with the Link With options in XSI that much, I'm more familiar in Maya and 'set driven keys' in that regard)

I also added empty expressions on the translateY and translateZ parameters for the mover so that you won't be able to accidentally move in in those directions and also made them non-keyable. Just for fun.

iirc = 'if I remember correctly'

Hope this helps, have fun!

[Falam]

Thank You