[SOLVED] How to transition from a normal object to FEM at a certain frame

[boyle 1]

Hi,

How can I transform a regular solid object to a FEM at a certain frame in my animation?

Been looking around but cannot figure out where to begin!

Edited February 8, 2017 by boyle

[Atom 1,209]

One way is to render them in both states then just cross fade the footage in your compositing app.

[boyle 1]

12 minutes ago, Atom said:

One way is to render them in both states then just cross fade the footage in your compositing app.

...which is what I'm doing right now as a workaround. 

Just figured I'd ask. 

[Butachan 27]

The set up will probably change according to what you need. Maybe you can be more specific about what you need your object to do. Basically if it is just an inert object that suddenly explode (exploding brains for example) you just simulate that moment. I am sure that is not what you need, but be more specific and maybe we can help.

[boyle 1]

33 minutes ago, Butachan said:

The set up will probably change according to what you need. Maybe you can be more specific about what you need your object to do. Basically if it is just an inert object that suddenly explode (exploding brains for example) you just simulate that moment. I am sure that is not what you need, but be more specific and maybe we can help.

Basically i needed an object to behave as a solid firm object and then suddenly become a soft, squishy object in mid-animation.

[foxel 3]

I'd do this as a hand-over to FEM on a frame of your choice

[boyle 1]

2 hours ago, foxel said:

I'd do this as a hand-over to FEM on a frame of your choice

Sounds as what I'm looking for! What's a hand-over and how do I do one?

[Butachan 27]

I'm not infront of Houdini, but inside the DOP network in the object creation node you have a creation frame. you can choose then the creation of the FEM object at a particular frame. Sorry I cannot be of more help.

[boyle 1]

1 hour ago, Butachan said:

I'm not infront of Houdini, but inside the DOP network in the object creation node you have a creation frame. you can choose then the creation of the FEM object at a particular frame. Sorry I cannot be of more help.

GOLDEN!

Exactly what I was looking for.

What's the common workflow to do the transition though? I.e to move the render flag to the "dop_import embedded" node within the geo object at the moment of the creation frame? Again, this may be a stupid question, sorry in advance!! 

Edited February 7, 2017 by boyle

[Butachan 27]

I just made this file at work (sorry I don't know if you will be able to open it). But doesn't really use anything unusual. Basically you create an RBD sim and then deactivate the sim at a particular frame. you activate on that same frame and create the FEM object. If you want you also create a switch that changes the model from the RBD object to the FEM object simulation. This may be not the most elegant solution. But the idea is to play with creation and activation frames.

Also this system will not transfer velocity or anything to the FEM solver. I am sure that there must me a better way to do this if you need to but like I said it depends on the necessity of you r project.

 

Best,

Nico.

 

RBDtoFEM.hip

Edited February 7, 2017 by Butachan
Addendum

[boyle 1]

@Butachan this is great and inspiring stuff! I really appreciate that you went through the trouble of creating this file to help look for a solution here.

It keeps hitting me that this may be the best community on the web I've ever seen, and I have yet to see evidence to refute that statement

Thanks again a million times!!

B