Hook modifier stretches cloth instead of moving

Question

I'm modelling a balloon and I'm trying to attaching a string to. The balloon itself is a solid mesh and the string is a cylinder with a cloth modifier on it.

I've tried following instructions from here and here but I'm still experiencing the same problem of it stretching the mesh/cloth instead of moving it all. Here's a gif demonstrating the output

And the blend file

Steps I took to make it:

1. Add an icospere and create a vertex group containing just one vertex on the base

2. Create a cylinder with some subdivisions and then add a cloth modifier

3. Select the vertecies at one end of the cyclinder and add them to a vertex group

4. Add a cloth modifier and use the newly created vertex group as the pin group

5. With the string's vertex group still selected add a hook modifier (in edit mode select Ctrl + H > Hook to New Object)

6. Move the Hook modifier above the Cloth modifier

7. Select the empty and add an object constraint > copy transforms and select the icospehre as the target and the vertex group.

8. Add some random movement to the icosphere

Is there a way to stop it from stretching the mesh?

Answer 1

Issue: You can't hook and then move Empty before running simulation.
Like now your vertex group goes through whole cylinder into Sphere center = initial shape is heavily deformed on frame 1 (in other words cloth shape is stretched).

Solution: ... just move Sphere center (with parented Empty) on top of Cylinder.

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Note: Specifically in your case - after moving Sphere on top of Cylinder ... re-add Keyframe on frame 1, duplicate to last keyframe, and Bake sim again.

Answer 2

I don't know what you did wrong, but here is a detailed description how it works:

1. select default cube -> Tab -> Edit mode -> S -> Shift-Z -> scale it down like this

2. CTRL-R, scroll up so you get some loopcuts

3. select 4 top vertices -> vertex group -> assign

4. CTRL-H -> hook to new object

5. tab -> object mode

6. select cube -> add cloth modifier

7. for shape choose your pin vertex group

8. select empty -> I -> Location (keyframe location)

9. move to frame 100 -> G -> Y -> move the empty a bit -> I (keyframe location)

10. result (depends on your speed/location keyframes):

of course then you can add your sphere and add a copy location modifier to the sphere which copies it from the empty.

Answer 3

Select the empty, put it at the center of the scene with AltG. Select the cylinder, remove its Hook modifier, move it until its bottom is at the center of the scene (or rotate it however you want but make sure that the vertices you want to hook are at the same position as the empty), select the empty, shift select the cylinder, switch to Edit mode, select the bottom vertices, hook to the empty with CtrlH > Hook to Selected Object, put the Hook modifier above the Cloth modifier:

Keep these vertices selected, press CtrlG to assign them to a vertex group, select the top vertices and remove them from the group, in the Cloth panel choose this vertex group as the Pin Group, it should work: