Making a fixed joint

[josemendez]

An update here, I went with simulating the softbody in local space with the bottom part of it being fixed. 
This is not ideal however, as the softbody does not affect the rigidbody it is attached too.
I'm wondering if I need to supply more information on what I want to do in order to get a reply?

Hi there,

I'm assuming you want a to attach the softbody to a rigidbody, and have both affect each other (moving the softbody would result in the rigidbody following it, and viceversa).

The only way to achieve this is trough pin constraints. Pin constraints are formulated exactly as fixed joints are in a traditional iterative rigidbody solver, so they can be made more stiff by increasing the amount of pin constraint iterations (and/or reducing the simulation timestep) and making sure the mass ratio between the rigidbody and the pinned particles is as close to 1 as possible.