yu zheng

thanks. I understand. But how can observe the effects of single parameter on cloth simulation, eg, the shearing or friction force?

I am studying the case in the book The Magic of Houdini, and have two problems.
First, I can not find the visualization tab in cloth dop object node to see friction or other force interactively, though it exits in the wire object. That part does no appear in the details view. My houdini version is the last one, v10. Could someone find the solution?

Second, when I try to finish the powerl line case, it does not work according to the steps in this book. If I write in the goal object box the name of the obdject in the wire glue constrain node, all the points were drawn to the origin point of the world space, rather than to contraint points on the wire.

But I find if I dose not use the method mentioned in that book and just set up constraint points on the wire by group without seting up goal object, the problem can be resolved.

How to use the goal object in the wire glue constraint ? Any suggestions are appreciated. Thanks.

Below is the hip file.

sorry. I added a new value w in the value tab of l-system. and also the command : “opcook -F”

the premise : FX
the rule: X=&(`ch(“w”)`)FX

but the l-system does update unless i change the generation number.

I do not understand why. Could you give me some hints? thanks.