turning a solid to a liquid

[Michael1]

Hi,

I was wondering how someone would go about the effect of a solid piece of geometry impacting with water but when the moment of impact occurs this solid object becomes a liquid. And then this liquid were to float on the surface much like how oil floats on water.

So a quick break down, a cube falls and hits some water. Then as it hits the water it turns into a liquid which then floats on the surface.

I hope thats clear, sorry about no reference material. I've tried search older posts but I couldn't see any that really matched this effect.

Thanks

[Netvudu]

On a first look sounds to me like using "Fluid from object" and an SDF container should do this, right? I guess you already tried that way?

[graham]

I was working on some tools like this for particle fluids about a year ago that would basically take a group of one or more rbd objects and use them to generate new particle fluids. The key was to group out the specific objects that were impacting, then use the objects in the group to create new particle fluid objects on the fly with the correct velocity and whatnot. The system would mostly work but it was never finished because of a few shortcomings in the way Houdini passes info to Sops at the DOP level that would basically prevent the possibility of having multiple objects becoming particle fluids at the same frame. r+d was unfortunately busy with other things so the project was put on hold until the relevant RFEs can be implemented. I'm sure a similar system could be used for PLS fluids but I can't remember what kind of impact information they pass along to RBDs, so you might have to come up with a better way of automatically figure out what is impacting.

[Michael1]

I guess you already tried that way?

Actually I have only just started to look into this area so was looking for guidance on which way to go. But I was thinking that wouldn't give the solid object the appearance of being solid, I'd like it to only be a liquid when the object comes into contact with the liquid. So as the tip of the object touches the liquid that tip is now liquid but the rest is still solid.

[Michael1]

Thanks Graham, I will try and look into this next week when I have a bit more time.

If anyone else has suggestions that would be great.

[anakin78z]

Well, in my head it looks like this:

You have an RBD object which falls and collides with a fluid. Check the rbd object for impact info. As soon as you detect an impact, The RBD becomes a source for your oil fluid, then gets deleted. This should fill the space where the rbd object was with fluid, which would then fall into the water/do it's thing.

Sounds right in my head... might work in houdini? You could probably take a look at some of the example hipfiles where the slug turns into gas to see how that's set up.

[Michael1]

Well, in my head it looks like this:

You have an RBD object which falls and collides with a fluid. Check the rbd object for impact info. As soon as you detect an impact, The RBD becomes a source for your oil fluid, then gets deleted. This should fill the space where the rbd object was with fluid, which would then fall into the water/do it's thing.

Sounds right in my head... might work in houdini? You could probably take a look at some of the example hipfiles where the slug turns into gas to see how that's set up.

Thanks

I had a look at the slug example, its interesting but not quite the look I was after. The main problem with this approach is it turns the whole object into a liquid at the same instance. I was more aiming for object to change as it came into contact with the liquid surface as opposed to all at the same time.