Hello there,

I would like to ask your advice in my problem. I have a tower and I want to do a meteor impact rbd sim with it. For making it mutch more Art directed I want to change the constrains under the sim. The upper part of the tower is nice if its stay together and not falling apart during the collapse (I can achive this with a stronger glue constrain), but before its hit the ground I want to change its constrains to weak for break it at the impact with the ground. But because of I am a newbie I dont know mutch about that. I found an option in the RBD Bullet Solver/Constrain page where I can switch the constrain after a certain frame, but I cant figure it out how should I use it. Also I cant find any help on the net for that and the help just say that:

Switch to Next Constraint

Constraint geometry with attribute values above the specified threshold will switch to their next_constraint_name if available or deleted.

Could you give me a little push in that please?

With Next Constraints, the constraints have next_constraint_name and next_constraint_type attributes which causes the constraints to, when broken, switch to this constraint name and type instead of being deleted.
next_constraint_name then becomes constraint_name and next_constraint_type becomes constraint_type.
Keep in mind these are the only 2 next_* attributes that get renamed this way.

Having the next_constraint_name be the same as the constraint_name isn't all that useful since they share the same attributes. For example, if both constraint_name and next_constraint_name are set to "Glue", since the constraints will have the same "strength" value (there is no next_strength attribute) when the constraint breaks due to an impact being stronger than the constraint's strength, the constraint is broken, switches over to the next_constraint (Glue in this case) and immediately breaks again since the impact is stronger than the constraint's strength.

If you want to change the constraints' strength over time, the simplest thing to do is to animate it in SOPs with a RBD Constraint Properties SOP node and add the "strength" attribute to the RBD Bullet Solver SOP's list of constraint attributes to override. On the RBD Bullet SOP, under the Constraints tab, Override Attributes, enable the Attributes and add "Strength" there.

Here's a hipfile with various examples.