Joint Acceleration Morphing tech showcase (Patreon)

Hi.

A month and a half ago, I laid out a rough plan for Naturalis 1.4 in this development status post.

The idea was to release a separate general joint angle morphing plugin, and then develop a new morphing system with new custom morphs for Naturalis. I've made some changes this plan, and I'm very excited to let you know what's coming!

Joint Acceleration Morphing

Firstly, when I released Body Weight, I talked about how it'd be interesting to morph regions of the body based on the pull of gravity or other types of forces pulling on the body's joints. The more I thought about that, the more obvious it became that this is the perfect place to start redesigning the morphing in Naturalis v1.4.

The way that muscles, skin, fat etc. droop on many soft parts of the body is very important for simulation and realism, and currently in VAM, this kind of morphing simply does not exist as a dynamic, physics based system. Except as implemented in TittyMagic and BootyMagic for their specific joints, although those systems are not driving morph values based on accelerations but based on changes in joint angles.

I've implemented the basic requirements of this new system. Since the morph values are just based on accelerations experienced by the joints, they are not influenced by the masses of joints (as configured in Body Weight, for example). I think keeping the morph values independent of masses is a safe approach in the first version.

Check out the below video to see the system in action. The morphs used here are just super basic test morphs, they exist simply to test and develop the system, and to illustrate the sorts of effects that can be created with it.

https://everlaster.vids.io/videos/0690d5b51a1de0c38f/naturalis-joint-acceleration-morphing-demo-1

I hope you can see the potential here! The main advantage to this type of morphing is that the morphs are automatically applied at correct amounts in any pose relative to any accelerations applying to the joints from any direction. Gravity is one type of acceleration, so changing the gravity settings in Scene Misc automatically has an effect on the morphing. Any kind of animation of the joints will also produce acceleration and thus affect a morph's value along the joint axis or axes that the morph is targeting.

Smoothing the Acceleration

The system implements a smoothing over time to ensure that the morph values don't change too rapidly in response to changes in acceleration. Depending on how the joint springs and dampers are configured in the physics settings of each joint control, the acceleration value can change abruptly. Smoothing the calculated acceleration value over a few frames essentially dampens it and the driven morph value will look much more natural. The system supports configuring different morphs with different smooth frame counts, so that on the same model you could have e.g. a jiggly belly morph using a low amount of smoothing, and a more dampened upper chest morph that just shifts the skin and muscle more statically.

Shapeshift: A Morphing Base Layer

"Shapeshift" is the name of a new module in Naturalis that handles joint acceleration morphing and joint angle morphing. Joint angle morphing will be similar to what JointCorrect does, but designed and written from the ground up as a new system.

I chose this name as it fits the idea of full body dynamic morphing (which I plan to eventually support), and it describes how things move into a new shape as the model changes pose. Also, shapeshifting is a form of magic, so there you go.

As a separate module, the base layer is active independently of TittyMagic or BootyMagic. I'm planning to initially focus just on the regions underlying and surrounding the breast and glute soft physics meshes: upper chest, frontal ribcage, armpits, upper thighs, lower back and so on.

The idea is that the new breast and glute morphing systems and morphs will be designed to work on top of the base layer. It only makes sense to start working on those once the base layer is more or less complete. Without going too technical - both the joint acceleration and joint angle morphing systems will be important to get right, since both of those can dramatically change the shape of the chest and hip areas, and those changes need to happen before we even get to breast and glute specific morphs that are driven by pectoral/glute joint angles and deformations in the soft physics meshes. For example, when gravity shifts breasts up as the model leans back, it also shifts up the entire chest region around the breasts, but things like collision physics and forces acting only on the breasts should not have the same effect on the surrounding chest area. Therefore the base layer needs to be separate from TittyMagic and BootyMagic, and the more specific breast and glute morphing systems need to be a layer on top it.

At a later date, it'd definitely be interesting to implement morphs for other regions so that we can simulate the effects of gravity and other forces on the entire body, including the face!

What's Next?

1. Create quality morphs for acceleration based adjustments. I'll try my best to get them to look as realistic as possible.

2. Implement the joint angle morphing system, and angle corrective morphs that are necessary for the chest and hip area base layers.

3. Support saving/loading presets in Shapeshift, design the UI for configuring the included morphs in a sufficiently user friendly way (the current UI showcased in the video is just a development UI)

4. Release the next alpha so you get to test and play around with these systems. They're unlikely to work ideally with the existing breast and glute morphs since there's a lot of movement and rotation etc. built in to those that should really be part of Shapeshift. It'll still be a work in progress at that point!

5. Design/update the breast and glute morphing systems in TittyMagic and BootyMagic and create new morphs specific to those. The details of this will become clearer once the base layer is closer to complete. The idea I've posted in the past about having separate morphs for moving, rotating and adjusting the shape will probably still be valid.

6. Allow custom morphs to be configured for the base layer as well as breasts and glutes, and stored with the plugin and/or portable sets that can be loaded or merge loaded.

It will take time to get the next alpha out. How long, depends mostly on how quickly I can design morphs that look good. I'll keep you posted!

If anyone is into 3d character animation and has any good resources or references to suggest that could be helpful in understanding the way that different body parts change shape in different poses, let me know! I'm trying to educate myself on this topic as I go to ensure the morphs aren't just based on what I think should happen, but also on what actually does happen to the body.

-everlaster