How to simulate a elastic stick?

Scripting Issues
1

How can I simulate the collision between a elastic stick and a soft body?

After collision, the stick would turn to be arc.

Is there any demo?

Thanks for any suggestion~~~

2

I think looking through these examples you will have an idea.
https://www.panda3d.org/download/noversion/bullet-samples.zip

3

Thanks for kindly reply. The 21_SoftbodyRope is similar to a elastic stick. But, how can I set the stiffness coefficient for the rope?

4

In fact, I would have done it differently. Created several segments from solids, such as capsules, and would connect them with a spherical constraint. Accordingly, I would further adjust the rotation restriction and stiffness. Visualization can be done through the bones of the skeleton by attaching a capsule to each bone.

https://docs.panda3d.org/1.9/cpp/programming/physics/bullet/constraints

1 Like
5

How to apply the rotation restriction and stiffness? Could you please provide more details? I could not find the relative api.

6

These are not function names, but actions that I would do with the help of this class for example.

https://docs.panda3d.org/1.10/python/reference/panda3d.bullet.BulletConeTwistConstraint

7

The BulletConeTwistConstraint.setLimit may help. But the BulletSphericalConstraint do not provide any method for stiffness.

In addition, the class document is a bit simple. For example:

setLimit(swing1: float , swing2: float , twist: float , softness: float , bias: float , relaxation: float )

There is no explanation for swing1/swing2/twise/softness/bias/relaxation. For example, what is the unit, and what is the range of the value.

Does the softness indicates the stiffness?

8

It’s the same thing, BulletConeTwistConstraint has an additional set of constraints. If I’m not mistaken, the examples show how the constraint is configured.