5 replies to this topic

[Scratch]

Hey Houdini folks,

I'm wondering how to simulate a wire which has a RBD object on each end.

I've tried to set up a wire (wire object), set up 2 RBD objects and used the "attach wire to surface" shelf tool  to attach each end to the corresponding RBD object (also set the constrain to "hard" to really make it stick to the location where I want it to be). But when I simulate this, the wire goes crazy!

What I want to do in the end is for example pull out a cork of a teapot. The cork is connected to a sphere (with the wire), the sphere falls down somewhere, and the cork is pulled out of the teapot. This is just an example, In general, I am searching for a solution for a common "weight - wire - counterweight" scenario.

It's kind of hard to understand how these wire-sims have to be set up and how all the constrains work. There are hardly no tutorials out there... I also tried to dig through the documentation, and got some basic sims working, but as soon as it gets a bit more advanced, I get stuck.

Maybe you can help me here! Would be great!

Thx in advance!

[bloomendale]

Scratch, on 22 July 2012 - 07:15 AM, said:

Hey Houdini folks,

I'm wondering how to simulate a wire which has a RBD object on each end.

I've tried to set up a wire (wire object), set up 2 RBD objects and used the "attach wire to surface" shelf tool  to attach each end to the corresponding RBD object (also set the constrain to "hard" to really make it stick to the location where I want it to be). But when I simulate this, the wire goes crazy!

What I want to do in the end is for example pull out a cork of a teapot. The cork is connected to a sphere (with the wire), the sphere falls down somewhere, and the cork is pulled out of the teapot. This is just an example, In general, I am searching for a solution for a common "weight - wire - counterweight" scenario.

It's kind of hard to understand how these wire-sims have to be set up and how all the constrains work. There are hardly no tutorials out there... I also tried to dig through the documentation, and got some basic sims working, but as soon as it gets a bit more advanced, I get stuck.

Maybe you can help me here! Would be great!

Thx in advance!

I'd constrain points of the wire to rbd objects and then use sopsolver to read the internal force attribute in these points on wire and apply it as force to rbd objects (point force DOP for example). THis way having actually one-way relationship you can mimic mutual one.
Sam Hancock has very nice example of this approach (http://ihoudini.blog...ck-in-dops.html)

[Scratch]

Hey!

Thx for the quick answer! I'm afraid to say that I don't understand a single word of what you say...
I think I already stumbled over Sam's work while searching for wire-sim examples, but I couldn't make any sense of what he wrote on his blog.

You have to know, I started out fresh with Houdini in February, and I might not have the needed experience to understand this advanced concepts yet, but I'll give it annother try!

[Wooshum]

Taking the wire-RBD simulation a bit further: what would be the most efficient way of simulating multiple wires with RBD objects attached to the end of each wire individually?

I have gone through and applied Sam Hancock's approach successfully to a single wire and RBD object combination but am struggling to find a good way to run this simulation on a larger scale, with multiple wires - short of importing each wire strand and rbd object individually into the DOP.

As a rough example of the type of scene I am trying to simulate check out the attached file.

Any help is much appreciated!

Attached Files

•  Multi_Wire_and_RBD.hipnc   308.26K   58 downloads

[bloomendale]

Wooshum, on 26 July 2012 - 11:07 PM, said:

Taking the wire-RBD simulation a bit further: what would be the most efficient way of simulating multiple wires with RBD objects attached to the end of each wire individually?

I have gone through and applied Sam Hancock's approach successfully to a single wire and RBD object combination but am struggling to find a good way to run this simulation on a larger scale, with multiple wires - short of importing each wire strand and rbd object individually into the DOP.

As a rough example of the type of scene I am trying to simulate check out the attached file.

Any help is much appreciated!

You can use Apply relationship DOP to apply constraint per object.

[Wooshum]

bloomendale, on 02 August 2012 - 02:24 PM, said:

You can use Apply relationship DOP to apply constraint per object.

Hey All,

Sorry for bringing this thread up again. I have tried a few times to use the Apply Relationship DOP with an aim to simulate multiple wires and RBDs together unsuccessfully. I have had a dig through the built-in examples but I am definitely out of my depth on this one.

I have attached a scene with both a single wire/RBD combination rig and the multiple wire/RBD combination rig I would like to simulate. If anyone could assist me in getting this simulation up and running whilst maintaining the wire/RBD force functionality it would be much appreciated!

Yours in confusion,

Dan.

Attached Files

•  Multi_Wire_Apply_Rel.hipnc   435.46K   49 downloads