I've just noticed that this seems to be standard - when you go into the Setup room the first bone in the skeleton, the one directly parented to 'Body' (so usually 'Hip' for a humanoid figure, but plain old 'bone_1' in my example below) doesn't have the x/y/zRotate joint parameters that all other bones have.

Here's an example, a 2 bone figure created in Poser's Setup room from an imported OBJ file consisting of two cubes.

Bottom cube's grouped to bone_1 and has only 2 joint parameters that I can edit.

Top cube's grouped to bone_2 and has five parameters

I need to be able to set up the x/y/zRotate joint zones for the bottom cube/bone_1.

How can I do this ?

The reason I'm asking is that the problem came up in post #67 on my topic over at Hivewire My rather infrequent, and possibly apocryphal, 'books project'. | Page 4 | HiveWire 3D Community. I know that I can sidestep the problem by inserting a dummy bone between 'Body' and 'bone_1', but I'd prefer not to do that if it's possible.

The only differences I can see in the CR2 between bone_1 and bone_2  that seem to relate to this are highlighted in yellow on the comparison screenshots below - bone_1 on the left, bone_2 on the right.

Firstly, the twistY, jointX and jointZ are in a different position and order in the channels section and are named in a different manner

Secondly, the twistY, jointX and jointZ of bone_1 all have two extra parameters - flipped and primaryParm.

I've checked Kuroyume's unofficial CR2 spec but 2004 was a long time ago and it doesn't really give me any clues, except that the order of jointX and jointZ is important

While I wait for somebody who knows what they're talking about I may just try editing a copy of the CR2 to make the bone_1 joint parameters similar to the bone_2 ones... what's the worst that can happen ? ;o)

Right, that didn't really help.

But editing the CR2 reminded me that each bone has a joint (and joint parameters) with its parent, and another joint with each child. So it would seem that jointx, jointz, and twisty are for the the joint with the parent bone (just one parent), while bone_2_twisty, bone_2_jointz, and bone_2_jointx are the joint with the child bone, the bone id being required because there can be multiple children (and the names without bone ids are already used for the joint with the parent anyway).

I'd guess that when you look at the joint parameters for a bone in the Setup room you're seeing the joint parameters for the joint between that bone and its parent, which appear in the CR2 as the  jointx, jointz, and twisty within that bone(bodypart/actor) but also as the bone_N_twisty, bone_N_jointz, and bone_N_jointx in the parent bone(bodypart/actor).

So while the x/y/zRotate of the second, third, etc bone in a figure bends the joint between it and its parent, the x/y/zRotate of the first bone in a Poser figure doesn't bend any joint, but simply rotates the bodypart. That's perfectly logical.

I think I need to insert a dummy bone. :)