Naturalis WIP: Opposing gravity (Patreon)

All things considered, things are progressing well, but it's been pretty slow going. With so many variables to take into account in balancing the settings, one needs to be very methodical and patient with testing and evaluating the changes to how the settings are calculated. It's a careful, iterative process of fine tuning every physics parameter against every other parameter for every mass and softness value (and that's a simplification).

Frankly, all that is kinda boring, but has to be done. I estimate that I'm probably about halfway through.

Gravity counterforce

A more exciting thing that I want to share with you though is a new feature called gravity counterforce. As you may know, in physics, weight is a force that is the product of gravity and an object's mass. In VAM's physics simulation, weight is automatically applied to the glute and breast joints, causing them to be pulled down in proportion to their mass and world gravity.

In Naturalis, gravity counterforce allows decoupling mass and weight by applying a force opposite to the direction of gravity. This means we can define mass to give us the amount of inertia we want, and use counterforce to adjust the weight.

The setting is shown in the Breast Joint Mass and Glute Joint Mass parameter windows. It's a percentage of the weight, so at 100% it cancels out all of the weight.

The reason I came up with this was that I wanted breasts to have more inertia when soft physics is disabled, but without the additional droop that increasing mass would normally cause. When soft physics is enabled, the mass of the small soft joints grant breasts (and glutes) overall more inertia than when soft physics is off (although the behavior is very different). I felt that in previous versions, breasts have seemed too light when not using soft physics.

However, gravity counterforce turns out to be pretty useful for glute physics too. The droop caused by weight on the glute joints is a very artificial and unrealistic effect because it treats the butt as something that just hangs off of the skeleton. In reality, most of the weight of the butt is supported by the surrounding muscles and skin around the butt (lower back, abs, torso in general, upper thighs etc.). 

I played around with the gravity counterforce and determined that in fact most of glute joint weight needs to be cancelled out. I'll do some more testing on that but for now it looks like something like 50-80% of gravity will be cancelled out depending on butt size. It makes the butt seem better connected to the body but still has the inertia to look great in animations. The smaller the butt, the more is cancelled out because a greater proportion of the volume of the butt is close to the supporting muscles.

Anyway, that's all I got for now. Thanks for reading!

-everlaster