Suspension Spring Skinning Problem

[hydrag]

Hi,

I'm currently working on an animation for a car suspension.

The game engine requires the use of Skin modifiers and a specific orientation of Dummy pivots.

They provided a working model of an animated suspension setup, which I tried to reconstruct meticulously.

The main difference besides the different color coding when the envelopes are visible seems to be that my spring compresses and stretches its mesh differently from the provided example.

Someone also suggested to use a quad mesh, so I created one from a helix spline but encountered the exact same.

So I went ahead and deleted the Skin modifier from provided project that was working properly and reapplied the Skin modifier to the exact same Dummies and Mesh while keeping all the settings the same. Picture 1 and 2 show the upper and lower bones in the original project and 3 and 4 show what happens after reapplying the Skin modifier.

In general it did work in our project however it kind of squashes the circular tubing of my spring instead of behaving like an actual spring would.

Any help is kindly appreciated,

Best Regards

[skarpovsGNG3A]

Hello, you should assign weight to each cross-section one by one like edge ring 1 - 0.1 edge ring 2 - 0.2 etc. Making it by hand is quite ridiculous, so use macro or script instead. First you should calculate how many loop rings your spring has and divide 1 by that number. Then you should assign this number as a skin weight and continue adding and grow selection. Here's simple macro you can use

skinOps.growSelection $.modifiers[#Skin]
skinOps.addWeight $.modifiers[#Skin] 0.002

Here's also video with a script which is really handy

https://youtu.be/WeMHXlW8Q6c