boob jiggling

[pronzilla]

I know, I'm obsessed.  Who'da thunk it?

This is a rather specific request, and based on certain assumptions about how the jiggling boobs work.  If I've mentally reverse-engineered it correctly, the boob jiggling is a simple physics model, based on (per boob) a solid rod[1], pivoted at one end on the "ribcage", with a mass at the other end, and a couple of spring-like entities[2] anchored to the mass and other parts of the ribcage. 

The whole assembly then just jiggles based on the accelerations generated by the animation (is there gravity in there too?) and drags the "boob" part of the model around.

Based on my extensive observations ( ) the mass and the stiffness of the springs appear to be constant - and thus large boobs don't seem heavy enough, and small ones do really strange things.  I'm not sure whether the length of the rod is constant or not.

Assuming I got all that right (and I'm fully expecting "nope, that's not how it works" as a possible answer) would it be possible to base the values in the physics model on the body proportions? 

As a first stab, I'd suggest something like mass based on X*Y*Z; rod length based on Y, and the stiffness of the springs based on Y*Z.  (where X/Y/Z are the boob size values from the XML). 

If I got my maths right, that should lead fairly inevitably to: small boobs don't jiggle much, big boobs bounce around a lot more, which seems right.

To really push the boat out, how about making the clothing "BoobHolder" value be floating point, and factor it into the spring stiffness such that 0=cotton vest, 1=solid steel corset and values in between provide variable support.

Does that make sense, or am I on drugs?


[1] stop giggling at the back.

[2] I have no clue what terminology is used in computer physics libraries - my sole experience of this stuff is high school/college level maths/physics classes (which were a while ago in my case) - so apologies if I'm not making total sense.

[Jak (ripened peach)]

The boob jiggling in Sex Sim does employ a relatively simple physics model, but just getting that to work in the Unity engine was very difficult. 

I hired someone to do it originally, and they weren't able to make it work.  I then turned to development community, and still no luck.  It was only after some deep thought and experimenting that I was finally able to do it myself, and that's what's in the sim now.  I even had someone recently contact me asking about how I did it, as they are making a game in Unity and had the same initial difficulties I did.

So yes, in the end I got it working, tweaked it some, and left it basically at that, until I added the "BoobHolder" value, which basically turns it off for certain outfits.

Anyway... it is something that I can look into, and possibly add some values to allow more control over things.  Ultimately I'd love to have multiple springs within each breast, for true jiggling of the flesh, but for now it's just one spring per, but if I tweak with it some I can probably add more variation as needed.

Added to the list.

[pronzilla]

Ah, I'm being spoiled by the complex physics models in megabudget games (or garrys mod, which hijacks a megabudget game engine) so I thought it would be something Unity included (I know, I'm clueless). 

That said, I wasn't expecting changes to the model[1] beyond adjustments to the numeric constants involved, based on boob size.  Still, if it was a pile of work to get it done in the first place, I appreciate it may be

[1] Seriously, I think the existing model works just fine for the 1.0-sized boobs. When I called it "simple", I meant relative to the kind of high-powered Finite Element Modelling that I briefly encountered during my university days.  Those are fantastic, provided you're willing to have some post-grad spend a month building the physics model, and use serious heavy-duty computing time to work out deformations at one frame per hour.  Hmm.  Maybe for the spanking add-on?