Organic breaking!

[Alcofialco]

Hello everyone!

I'm new in Houdini and once when i learn some stuff on Vimeo i find this: 

 

Now I struggle for some days to try to repeat this.) With simulation I had no problem: take a Tube and assign Fractured Solid Object, then I Dopimport simulation from AutoDop to new geometric node. My main problem is to receive that organic shape on new parts and make his smooth. I am not sure but seems i solve now how to get a displace on inner faces of geometry. But how to smooth geometry? VDB or Particle Fluid surface lose UV position.

What i have now:

Thank you!

 

OrganicSimulation.hipnc

Edited April 24, 2016 by Alcofialco

[Alcofialco]

Hmm.... No one from monsters of Houdini knows how this to resolve?)

[acey195]

voronoi fractures are likely to create a bit sharp geometry, you will have to smooth it quite a bit if you want to use that directly.

You can try using the subdivide SOP to better keep the UVs that you have. but to get organic chunks,
you may have to recombine certain fragments using VDB, which would mean losing your UVs again.

If rendering time is no issue, you can just bake the texture data into the vertex attributes and render it that way without any UVs.

or you could find a way to reproject your UVs somehow.

[Alcofialco]

Thanks for advice! 

But when i try to subdive a geometry this force me to keep primitive in tetra, and that don't let me import to AutoDopNetwork. How to resolve this?
 

[Spyrogif]

To get this kind of effect you should try POP Grain instead, it's very effective for this kind of look and it should be less time consuming.

For simulation use very high clumping stiffness and higher kinetic value than default.

For meshing : use vdb from particles, do some vdb magic (smoothing, contract, expand or whatever) then convert your vdb to mesh.

[Spyrogif]

A low res test scene to show you the idea

grain_slicing.hip

[Alcofialco]

10 minutes ago, Spyrogif said:

To get this kind of effect you should try POP Grain instead, it's very effective for this kind of look and it should be less time consuming.

For simulation use very high clumping stiffness and higher kinetic value than default.

For meshing : use vdb from particles, do some vdb magic (smoothing, contract, expand or whatever) then convert your vdb to mesh.

Thank you! I try it right now!

[Spyrogif]

Oh and keep increasing clumping stifness and kinetic to get a more muddy less liquid look. I've just try to triple this values in the .hip i post and it became closer than that you are looking for.

At the meshing stage, decrease influence scale to something more blobby.

It's a good idea to increase substep to this kind of rapid motion.

Edited April 27, 2016 by Spyrogif

[Alcofialco]

1 hour ago, Spyrogif said:

A low res test scene to show you the idea

grain_slicing.hip

Sad but your file crashed Houdini everytime.(((

 

Quote

oplib:/Vop/addconst?Vop/addconst Error(25): script unknown identifier descriptiveparm
oplib:/Vop/mulconst?Vop/mulconst Error(25): script unknown identifier descriptiveparm
oplib:/Vop/divconst?Vop/divconst Error(27): script unknown identifier descriptiveparm
oplib:/Vop/subconst?Vop/subconst Error(25): script unknown identifier descriptiveparm
6480: Fatal error: Segmentation fault

 

Edited April 27, 2016 by Alcofialco

[Spyrogif]

houdini version ?

 

[Alcofialco]

14 

 

[Spyrogif]

my setup is coming from H15 no more H14 on my computer.

But you should be be able to create the same thing on 14.

Do a caped tube who's gonna be the "thing".

Do the slicing object.

then select the "thing" and turn it to wet sand via the grain tab.

Select the slicing object and turn it to RBD object.

Add a dynamic ground.

Add some velocity to the slicing object in DOP (RBD object node) to make it going through the thing.

Then go to the pop grain node in dop.

change Scale Kinetic to 2.

In the clumping section change stiffness to 1e+008

Then go the geo node grain_particles>add a vdbfromparticles node >adjust particles separation (you could start with .025)

add a convert vdb>turn it to Polygon Soup

 

and you should be good to experiment with this.

This is a basic setup feel to experiement with the popgrain node in dop to get the dynamic look you want.

 

 

[Spyrogif]

If you want to learn more about popgrain you should look at this.

 

[Alcofialco]

5 minutes ago, Spyrogif said:

my setup is coming from H15 no more H14 on my computer.

But you should be be able to create the same thing on 14.

Do a caped tube who's gonna be the "thing".

Do the slicing object.

then select the "thing" and turn it to wet sand via the grain tab.

Select the slicing object and turn it to RBD object.

Add a dynamic ground.

Add some velocity to the slicing object in DOP (RBD object node) to make it going through the thing.

Then go to the pop grain node in dop.

change Scale Kinetic to 2.

In the clumping section change stiffness to 1e+008

Then go the geo node grain_particles>add a vdbfromparticles node >adjust particles separation (you could start with .025)

add a convert vdb>turn it to Polygon Soup

 

and you should be good to experiment with this.

This is a basic setup feel to experiement with the popgrain node in dop to get the dynamic look you want.

 

 

Hugest thanks for your complete answer!!! But are you sure the VDB won't lose UV? When i tried the same with FEM (VDB->Convert) my displace map moves every frame.((

[Alcofialco]

Just now, Alcofialco said:

Hugest thanks for your complete answer!!! But are you sure the VDB won't lose UV? When i tried the same with FEM (VDB->Convert) my displace map moves every frame.((

Look at video on 2th and 3th simulation - displace map the same and it hold on object, at the same time interior face was dicplaced too. I did it with static mesh but how does it with liquid mesh?

[Spyrogif]

You could deal with this problem using rest position and attribute transfert.

According to the look you need i would not use uv. Only procedural shading, rest position and attribute tranfert.

"Fix particle" position with rest position then transfert them to mesh using attribute transfert. 

Edited April 28, 2016 by Spyrogif

[Alcofialco]

OFFTOP

Now i playing with grains and everytime when try to make surface from grains i receive on a render the same grains, which is placed on each points of new surface. Why does it happen? How to delete grains?

Edited April 29, 2016 by Alcofialco