"Honey Select" pinch analysis

The article editor that breaks CSDN is too difficult to use, and it will be exhausting to pass a picture. I will turn it over after I finish writing it in Zhihu: https://zhuanlan.zhihu.com/p/28471808

Regarding the pinching system in the game, there is very little information about how to do it. I remember that only "Tianya Mingyue Knife" has shared it. Some time ago, I followed a public account for VR resource sharing, and often pushed HS's pinching works, so I only It aroused my curiosity and decided to find out.

The reason why HS can have such a strong customization ability is because of the existence of third-party MOD tools, players can freely import and export resources in the game, which also opens a back door for us to analyze the implementation mechanism of the game.

As we can see in the above image, the face has many bones, try to export the model and analyze it:

For the bones on the nose, do translation/rotation/scale, well, it looks like pinching the face is what it is.

For example, the nose wing bone affects this vertex, then we can adjust it to produce the following effect:

like the chin

The bones are used to pinch the face, what about the facial expression animation?

After analyzing the specifications of the model resources, it is found that there are a lot of morph animations. That is to say, the head bones in HS are all used for pinching faces, and the expression animations are driven by MorphTargets .

The body can't also use MorphTargets to perform movements, can it?

After analyzing its model resources, it is found that the number of MorphTargets is 0, and the number of bones exceeds the previous empirical value.

Looking at its skinning information, it can be found that the names of all the bones that affect vertices have the word "_s_", and their parent bones are the bones with the same name without "_s_". That is to say, in the HS body skeleton, the parent bone is responsible for animation , the child bone is responsible for skinning .

There are 67 adjustment parameters for the female character's face in the game:

There are a total of 34 adjustment parameters for the female character body, 2 of which are physical parameters and have nothing to do with bones

Let's see if these sliders can correspond to the bones one by one:

对于"鼻子整体上下"来说, 的确是只需要调节NoseBase的Y值就可以了, 我们需要做的就是根据滑杆在最大值和最小值之间进行线性插值.

对于"眉毛角度Z轴"的调节, 这时只调节一根骨骼就不对了, 需要左右对称着来. 也就是说, 有一些调节项需要同时调节左右对称的两根骨骼.

对于"眉毛左右位置", 如果在直线上两个端点之间进行插值, 很容易就跟面部三角形穿插了. 所以这里的插值路径只有最大值和最小值已经满足不了需求了, 而是需要按照曲线进行位置插值, 并且配合旋转插值贴合面部的法线方向. 也就是说, 一个调节项的插值可能是基于曲线(或多个关键帧), 而且可以同时影响骨骼Transform的多个分量.