When I open the Joint Editor, only some groups show both start and end points; others show only origin while the EndPoint boxes are greyed out.  Why?

I think it causes this: 
When the wheels on my figure rotate to exactly 180 degrees on the X axis, PistonB (and its children) rotates -10 degrees on the Z axis.  Every other position is perfect.  How do I fix that?

Quote - When I open the Joint Editor, only some groups show both start and end points; others show only origin while the EndPoint boxes are greyed out.  Why?

Only the last bone in a chain will show the EndPoint boxes, for the others, the centre point of the next bone is treated as the end point (I can't remember if this is true where a bone has more than one child).

I think that Poser realizes that there is more than one child and enables the EndPoint to be set - either that or it finds the median of the children's Origins and uses that (?).

When building rigs in the Setup room, Poser uses the origin of the first child you add as the endpoint of the parent bone.

Interesting.  For instance, with PointAt I'm using an average of the vectors to consider as the 'EndPoint' for the Origin-EndPoint vector that points at the target.  Seems to work with tests but then, with Poser, ten-thousand tests isn't enough to deduce anything with certainty.  What I'm seeing for a figure hand in Poser is the average of the childrens' Origins.

JOINT editor? Is that legal?

Only if you inhale :)

Any idea why at 180 degrees rotation the child group of the wheel rotates off the Z axis?  I dreamed last night (happens when I spend three days rigging nonstop) that it might be because the joints are all centered at X= 0.0.  Should they be slightly off center?

It is difficult to visualize without knowing what the model looks like. Would you be able to post some screen shots?

Quote - Only if you inhale :)

Oh... OK. hm... is it legal if inhale or does that mage it illegal? hm... nevermind. i dont smoke that s*** anyway  :laugh:

Quote - It is difficult to visualize without knowing what the model looks like. Would you be able to post some screen shots?

Yes, Phil.  I'll get some for you now.  Meanwhile, this thread has some other shots and an animation    http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2719401

*Only if you inhale :)

*:thumbupboth:

Stop boging the Joint Editor.

Here's the example of which I spoke.  lHand is pointing at the sphere, I moved the sphere back to see the alignment with the children fingers.  Looks like the median to me.

> Quote - It is difficult to visualize without knowing what the model looks like. Would you be able to post some screen shots?

The error occurs only when the wheels are rotated to 180 degrees, not at 179 nor at 181.

At any other setting it is fine.

Here is an animation.  At frame 16 the error is highlighted with a red arrow.

It is very hard to tell, but I think the error is that something (one of your "point at" functions) is over-extending. Sorry, don't know how to describe this in English, but it is like the object has gone beyond the limit, and is trying to get back.

Mmm, that sounds like gibberish. Let me try again.

Somewhere one of the joints is going beyond the limit of either it's translate or rotate, and is still trying to point at something, but what it is trying to point at is now behind it.

I will try to explain with a picture. The end point of the green piston points at the red dot. If it moves in such a way that it can no longer point at the red dot, then it will twist it's parent, etc, to still achieve the instruction to point at. That is why you have to always keep the point at targets far away, or in such a way that they can't cause illogical movements.