Constrain Hard Body sim to Wire sim?

[Anti-Distinctlyminty]

Hi all, 
I'm trying to set up a simulation where I shall have some rigid bodies stick to certain locations as much as possible (spring constraint maybe?) 

As you can see in the image I have a wire simulation. In that simulation the wire coils around some objects. I need these objects to remain within the coils. 
In the file provided there is geometry in obj > chromatin > NUCLEOSOME_CONSTRAINTS. This defines the point locations that I would like the pieces attached to. 

tldrl; How do I constrain an RBD fractured object to a certain location? 

 

 

constraints.zip

[kungFu]

you could write out the geo from the first simulation then use a point expression, rivet, etc.. to stick em.

Do you need some action on the pieces you want attached?

 

-james.

[Anti-Distinctlyminty]

you could write out the geo from the first simulation then use a point expression, rivet, etc.. to stick em.

Do you need some action on the pieces you want attached?

 

-james.

Yeah, I would like the hard bodies to react to the wire (just a one way interaction is fine as it is currently set up).

How would I pin each of the pieces in place? I guess I need one constraint per purple thing, but I just don't know how to set it up :/

[kungFu]

Hi Anti_Distinctlyminty,

 

I took a look at your file and was finding it very slow. The geo is heavy. You could sim on proxy objects and then sub in the good stuff.

 

You could create a glue network, but this is more often used for creating things that break eventually. Like a breaking window, some pieces fall, some don't.

You would set this up outside the DOP (where ever you got your groups for the purple things coming in would be best).

 

rbd constraints are ok. I would try dropping a sphere and clicking the shelf tool for constraint and look at the result.They can be added at the end of your autodop network. for example, a rbd pin constraint.

You could use a point expression to pick a point on the spring. For example if the point on a spring closest to a single purple thing was point 21, inside the rbd constraint for the x position

you would put point("../spingthing", 21, "P", 0) the Y position would get point("../springthing", 21, "P", 1).... etc. where 0, 1 refer to x and y. search for point here: http://www.sidefx.com/docs/houdini15.0/expressions/

 

I'm not sure of what the forces you want to see are, this might not work. A pin will maintain distance, but it will swivel.

 

 

 

james S.

[Anti-Distinctlyminty]

Hi James,

I've attempted to do that, but the RBD pin constraint nodes just complains that I have a bad node reference. I'm not really sure what to do :/