TittyMagic 6 alpha 1 showcase and change log

Gentlemen, ladies, let me introduce to you the first alpha of the next major version of TittyMagic. It was supposed to be v5.3 originally, but calling it version 6 makes more sense since the whole physics system is getting an overhaul, among other things. There's a lot to talk about!

Before you continue reading, this video shows the new physics in action. As you can tell, I can't stop playing with the funbags, haha 😂

Release post (Enthusiast tier): https://www.patreon.com/posts/77826152 

Physics system overhaul

The new physics system adjusts the Fat Spring, Fat Damper, Fat Mass, Fat Collider Radius, Fat Collider Depth and Fat Distance Limit parameters individually for every soft joint on the skin surface. The first thing is that the values are set along a smooth gradient from the areola joint to the outermost joint at the base of the breast, and the values end up being slightly different for every joint as a result. The target values for the gradient are roughly similar to v5.2 default group target values, e.g. fat spring is lowest for the main joints and highest for outer and areola/nipple joints.

But more importantly, when using local distortion physics, the individual joint values are updated in real time in response to the joint's distance from its neighboring joints. The change in distance can be categorized as compression (distance decreases) and stretching (distance increases) and it depends on the physics parameter what happens in either case.

The alpha version is setup with these defaults for local distortion physics:

• Fat Spring increases sharply when joints are either compressed or stretched - breast fat is softest when no forces are acting on it, but becomes locally more rigid to prevent further compression or stretching
• Fat Damper increases as well with both compression and stretching, but not as sharply
• Since Fat Mass defines density, it increases when joints are compressed
• Fat Collider Radius increases when joints are stretched, more accurately filling the larger local volume, this helps prevent poking through the collider gaps
• Fat Collider Depth increases when joints are compressed, making the colliders hug the colliding object causing the compression more tightly
• Fat Distance Limit does not have a distortion effect by default, but you play around with that and see how it looks

There's one significant problem: In this alpha, local distortion physics only works as intended when the person is upright (gravity acts down along the chest). Initially, I figures this system would work great regardless of the person's pose, but it turned out that the physics values change too dramatically when the overall breast shape changes. 

One solution to fix this so that the adjustments work as intended in every pose would be to calibrate the average distances to neighboring joints for every pose (lean forward, back, left, right, and upside down), then interpolate between those averages depending on the chest angle. Sounds complicated and it would increase the time the plugin takes to calibrate, so... we'll see.

New physics defaults

The default values for every physics parameter have been tweaked as well, with the local distortion adjustments in mind. I'm trying to go for a slightly hyper-realistic outcome where the breasts are extra soft and jiggly in their resting shape, but with fluctuating local rigidity when collision and animation cause distortions in the skin curvature. The idea is for breasts to be very soft but properly resistant to compression (and stretching), something that hasn't been really possible in VAM before!

• Main joint spring decreased a bit
• Main joint damper decreased (about half)
• Fat spring decreased a bit
• Fat damper between about one third and one half of before
• Fat mass just slightly lower
• Fat collider radius reduced a little as well
• Fat collider depth is now 0, so that skin collision is exact when there's no local distortion
• Fat distance limit unchanged
• Fat back force increased a little bit (max force and threshold unchanged)
• Gravity physics: Main joint target angles are reduced just a little for soft breasts

Revamped soft physics parameter UI (WIP!)

An explanation of what's going on:

The value slider showing the current value is gone, since there is no single current value. Instead, averages for the usual soft joint groups are shown on the left, and the values of individual joints can be inspected by selecting a joint from the popup menu. The individual values show

• distortion in millimeters, this is the change in distance to the joint's neighboring joints (0 mm = the current distance is the calibrated distance)
• change in value: how much the parameter, in this case Fat Spring, is changed because of the distortion
• final value: the base value of that joint plus the change due to distortion

The local distortion physics section allows you to configure the magnitude of the effect and how easily the effect is applied as the distortion increases. 

The effect slider has a range of -3 to +3 and defines how much the parameter's value increases or decreases relative to how much it can increase or decrease. It's not quite exact but you can settle on a good value by experimenting with it.

The sensitivity basically means that at 1, the effect is applied linearly, so that even small distortions cause the value to change, while at 0 the effect is applied along a steep S-curve which prevents the value from changing easily, but once there's enough distortion it'll change pretty sharply.

The "Show Distortion Grid" toggle visualizes the connections between the soft joints and highlights them according to the change in value due to distortion for that parameter. You can see this in effect in the post's image.

Updated friction implementation

• Default friction without adaptive friction is now 0.8, up from 0.6
• With adaptive friction, dry skin friction is now 1 (max)
• The effect of gloss on friction is much more concentrated at the high end of the gloss slider
• The effect of specular bumpiness on friction is reduced, especially for low bumpiness values

Other

• Fat Back Force parameters no longer have the group based multipliers (they were not really needed, didn't want to keep the group based implementation floating around just for them), but you can still use the overall offset as usual
• Fat Spring used to be adjusted dynamically based on overall breast depth, this is no longer the case because local distortion physics is better
• In the Fat Collider Radius and Fat Collider Depth windows, adjusting offset no longer automatically visualizes the colliders, just the toggle works. Only the left breast's colliders are visualized now, and there's a slider to adjust opacity.
• In the Morph Multipliers tab, Back slider is renamed Depth In, and Forward slider is renamed Depth Out (their exposed trigger targets are also renamed similarly)

(!) Limitations and known issues in the current alpha

• Local distortion physics only works correctly when the person is upright, as mentioned above
• Fat Collider Radius doesn't yet decrease automatically in response to compression
• Fat Mass doesn't yet decrease automatically in response to stretching 
• I haven't yet tested everything with different breast sizes
• The softness slider value is not yet taken into account in the way that local distortion affects breasts; the idea would be for softer breasts to have less resistance to compression and stretching
• The physics gradient from tip to edge isn't yet customizable, I have to think about what knobs and dials I want to expose to make customizing it intuitive
• The "Apply Only To Left Breast" toggle doesn't yet limit your manual change in the distortion effect to the left breast... I'm, not sure how useful that would be, perhaps this toggle isn't that useful anyway and needs to be scrapped
• Adjusting the distortion amount or sensitivity currently doesn't add an asterisk to the parameter's button in the main Physics Params tab view

Upcoming stuff

Overcome the above limitations, the biggest one being proper functioning of local distortion physics in any pose.

Also, when adding sliders for customizing the gradient for each physics parameter, I will also add a way to visualize the gradient separately from the distortion effect.

What else will be included in TittyMagic 6.0, you ask? Well, thanks for asking! I want to revisit the hard colliders implementation and try to optimize them further to ensure the final collision physics is as good as it can be without something like custom hard colliders. 

Of course, all of this will need to be ported to BootyMagic. That will take some time to do since there are so many code changes - but once that's done, I can proceed with setting up the default physics for all softness values and butt sizes. Local distortion physics for the booty should be awesome!

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Enjoy it. Thanks! 👍

-everlaster