Hey there!
Does anyone know if there is a way to setup Conetwist constraints entirely using the SOP level tools? Say I have an upper and a lower leg of a complex robot model. Both leg parts are build from many smaller components. It will be cut/ hacked apart in simulation for example. For the knee joint it seems to me that a Conetwist constraint might be a good way. Similar to what the help doc shows in the ragdoll example.
As it happens the rbdconstraintproperties does not offer Conetwist as a setting, nor can you find it in the rbdconstraintsfromrules. I thought it would be very convenient to use the group to group functionality to constrain the lower to the upper leg, but that seems not possible/ the way to do it.
The bulletsolver SOP then again has the setting to support /enable conetwist but I would need many different types of Goal axis, Motor settings based on the type of joint in the robot.
When I make the node editable I am overwhelmed with the amount of nodes in it.
In short: I want to use many different Conetwist constraints within SOPs, connecting bodyparts, each consisting of many individual components having various types of Glue/soft constraints themselves.

Thanks!
Ben

The RBD Constraints from Lines/Curves/Rules SOPs only create the constraint geometry, they do not add any specific RBD constraint type attributes. RBD constraints of all types are represented by 2 point polylines pointing to 2 named pieces which means the same constraint geometry can represent every type of RBD constraint, glue, soft, hard, conetwist, spring and slider constraints.

This means in most cases you'll need to use an RBD Constraint Properties SOP after the RBD Constraint from * SOPs in order to configure the new constraint geometry.

Typically, conetwist and slider constraints want to be configured quite specifically for each constraint and therefore have been omitted from the RBD Constraint Properties SOP as this is meant to configure a larger number of constraints at once.

Configuring conetwist and slider constraints in SOPs is something we know is sorely missing and is being worked on.

In the meantime you'll need to add the various attributes to the constraint primitives yourself.
The attribute names (and type) should match the constraint DOP parameter names in order to override the global settings. This is fairly well documented in the various RBD * constraint relationship DOP nodes documentation.

Anyone have an update for this? The parameters are in the solver to be enabled.

I can't say too much other than this should be a lot easier to setup in the next version of houdini with some significant improvements to the cone twist constraints in particular.