The ability of fix vertex of spline during physical simulation
Sometimes, I want to use curve/spline to make strings or serve as a guide for other objects to deform/follow. It's ok to do it statically, but I want to have ability to make it work during physical simulation. For example, a person is holding a string, in which one end of string is fixed, while the other end is dragged by gravity and freely moving with wind or so. To summarize the topic: I wish to have the ability to fix/pin vertex of spline during physical simulation. Just like you can pin specific vertex group in cloth simulation of meshes.
Here is the current status about how "spline dynamics" works in blender, please point me out if I am wrong:
- Currently up to blender 2.81, spline can simulate soft-body dynamic. However, it will stay in the air if you have the goal, and will just fall with gravity if I turn goal off. In soft body dynamics, there are sockets to select vertex group, but we can't assign vertex group in a spline, so the socket is rather useless.
- Hook modifier is supposed to hold vertex to a object. But as soon as you activate soft body dynamics, hook modifier will be overwritten and thus becomes useless.
Potentially, there may be work around to do the work for a string. However, sometimes I want a spline to serve as a guide for other objects to deform/follow a moving spline. In that case, I need a spline instead of having a mesh. Either way, a proper spline dynamics is important in my understanding.
If you have any workaround or thoughts about this, welcome to comment.
3 Comments
IMO the bigger need is vertex groups in splines. I'm not really sure why it isn't possible. In the meantime, there are workarounds, but I don't really understand why the softbody goal isn't doing what you want.
* @Josephbburg * Would you explain to me the workaround? Or did it mean you know how to use goal to do what I want, while not having ability to set a vertex group? In my case, if the goal is checked, either the spline will just twiching on the air by default or will just falling from the air after tweaking the values. The current workaround I know, is to use method for people to physically simulate collection of volumetric hair. I can set many segments of bones, cube. And there should be equal segments of empties that uses rigid body constraint to hold all pieces together. With "rigid body simulation", object will move. Then we can possibly copy location and rotation of these rigid body cube to the bone. and parent mesh to bone. This is a very huge workaround to make a spline dynamic, while we should be able to use "spline dynamic". That's why I think this is somehow seriously needed in blender.
* @Hoffman * There is a way to set the goal value directly with the w-menu in curve edit mode. That way, you can set goal=1.0 for pinned parts and goal=0 for floppy parts. I think there's a tool for smoothing it, too, but that kind of thing would be trivial to write in Python, too.
If you already knew all that, then start a Blenderartists forum post and mention it here with a little more information. That's a better place for discussing workarounds that are involved (like this is).