Hopefully I can explain this problem in an understandable manner...

I'm making some multi axis JCMs. 2 rotations. A bend (xrot) and a turn (yrot) simultaneous.

I have 2 of these JCMs, one that works when the actor bends 40 degrees and when it turns 40 degrees, simultaneously. The other is identical in the bend parameter but the turn is -40 degrees.

Both are set up using the value operations tab, a delta add and a multiply illustrated below. The math is correct and the JCMs work as intended. Limits are set on the masters for these 0 to 1.

Here's the problem.

Example, when I Bend the figure -40 degrees and turn the figure 40 (or -40) degrees one of the above JCMs kicks in even though they were not set up with a negative bend. What's happening is the value operation JCM kicks in regardless if the negative value is being addressed, as intended, by those above JCMs, as shown below. See that the -40/-40 is being effected by the 40/40 value operation. 

The problem is making it so I cannot create multi axis JCMs in the negative bend range without a sort of canceling out effect.

Is there a solution to this rather peculiar value operations limits quandry?

Thanks.

I'm getting a feeling the solution involves a Subtract...

Nevermind. Solution found via a value operation subtract dial.

Basically created an empty master, adding a value operations subtract to the effected JCM tied to that master and linked the master off to the negative rotation of a bend parameter dependency. So the intended positive JCM is turned off when the bend goes into -1 degree of rotation.

I'll rinse and repeat as relevant, which actually kills several birds with one stone. The subtracts are easy to make, I was already adding a subtract off dial to each JCM (to be overall controlled by regional and a global offs)... in other words not an extraneous dial.

So, is this quirk a BUG or a FEATURE of Poser's gizzards ??

NikKelly posted at 7:47 AM Mon, 28 November 2022 - #4450464

So, is this quirk a BUG or a FEATURE of Poser's gizzards ??

A very powerful feature, only slightly documented. A bug of my math abilities, exacerbated by the barely documented feature... I've managed to plow through my shortcomings in that area well enough to do the things I need to do. Considering that this stuff used to have to be hacked into files via text editing, a very handy feature that's not at all a quirk but just operator inexperience.

There's an easier way to achieve this. Make the primary driver (the abs rotations in this case) a keyed dependency (ValueOp) Only give it 2 keys. The "one" value will go where ever the joint needs to be rotated to and the zero is usually zero. (You can get more tricky with this by fiddling with the active range of the keys)

The point is that when the joint is rotated the other (wrong?) way the the values will be zero. So zero times any thing is still zero.

The OpTimes will be set up the same way

If you look at the dependencies for LaFemme as an example there are several 2 axis JCMs on her shoulders. JCMlArmFwdUp is a example that one axis is negative.

Keyed Dependencies on the driving dial ...

The Value ops on the controlled morph ...

I recommend setting the scalar for the OpTimes so it will be 1.0 at the desired rotation. So 1 divided by what ever the rotation is. In this example it would be 0.022. That way all the "makes my brain hurt" type math is done at the lowest possible level. You don't have to figure out what 1 / Xrotation / Yrotation is.

Pay no attention to the bottom two dependencies. Those are for making the it possible to shut off JCMs from a master switch in the body and an override for manually controlling the JCM when it's disabled.

P.S. All this is a highly exploited BUG. It's just that it turned out to be a really useful bug. It has since become a legitimized and evolved into a feature.

Oh cool. I'll do some testing with this new bit of lore :)

"I recommend setting the scalar for the OpTimes so it will be 1.0 at the desired rotation. So 1 divided by what ever the rotation is. In this example it would be 0.022. That way all the "makes my brain hurt" type math is done at the lowest possible level. You don't have to figure out what 1 / Xrotation / Yrotation is."

A good bit of advice there, thanks. Funny story with that, I had initially been trying to calculate the negative into the actual division formula via a calculator when you said "just add the minus" to scale factor way back in an old post. It suddenly dawned on me to just add the minus to the calculated result in the scalar number field... that one had me stumped for a bit a year ago lol. I've since managed to create 3 axis JCMs successfully following your advice...

As an aside this is pretty cryptic stuff but it's one of my favorite things about Poser. Unfortunately very few people seem to know how to do this stuff, it's a bit worrisome to think that all of this lore might be lost when individuals such as yourself, nerd, depart from the Poserverse someday...

Also the offset parm default value in relation to Animated Centers advice was very useful.

Thanks once again from this grateful Poser tinkerer :)