dynamic ice fracturing (SOLVED)

[Diego A Grimaldi]

Hi everyone,

 

I'm trying to create a dynamic cracking ice wall. What that means is that I have a wall geo that needs to be cracked (multiple times possibly) based on an impact object (or anything really) but it cannot be pre-fractured due to the ice nature.

 

I've been trying by haking the fracture parm (voronoi fracture config obj) node and tried with a SopSolver in DOP as well with no decent result.

 

I was wondering if you had any ideas on how to approach this.

 

Here's a photo of the ice crack shape I'm trying to go for:

 

https://www.flickr.com/photos/dreamofdata/5434655197/in/photostream/

 

Thanks for any help.

 

Diego

Edited June 2, 2015 by Diego A Grimaldi

[ciliath]

well, what's nice about ice is that the cracks usually appears instantly (or in spurs)

which means that if you want to sim it you can just switch the normal wall to the pre-cracked version the moment the wall gets hit.

[Diego A Grimaldi]

Well in our case Felix we need to crack it gradually, not all together...That's the tough part...switch is not gonna work

[MENOZ]

if you manage to create the final cracked shape with all separate pieces (playing with voronoi, trace sop, volume fracture in a for loop, or something like this

), maybe you could try to reveal the internal crack geometry with some parameter at rendertme.

 

if you don't necessarily need having all pieces separated and you only want to see the cracks you could use some curves and control each crack line independently.

[Diego A Grimaldi]

Hi Andrea,

 

Thanks for the reply. Artem's tool seems quite nice I'm gonna check it out now. I'm already playing with the ideas you mentioned, I wanna see how far I can push this technique.

 

I'd be glad to hear any other approach to this as well.

 

Thanks!

[georgeivan]

Just a shot,did you tried with PBD?

[Diego A Grimaldi]

I can't cuz I'm on H13...and how would you use PBD for that anyway?

[Ratman]

Dynamic fracturing works in H13 with packed primitives. You can look at generating your impact data and use that to drive the fracture generation.

 

https://www.sidefx.com/docs/houdini13.0/nodes/dop/voronoifracturesolver

[Diego A Grimaldi]

Hi Rick,

 

I have been trying to use the impact data coming from a SopSolver to then use in a voronoi fracture and just use that at the moment of impact, but the problem is that even in that case the entire geo is fracturing, not just a little part of it.

 

But if I'm missing something maybe you can shine a light on what you mean exactly.

 

Thanks

[tricecold]

Hey Diego, I dont think you need a simulation for this, I think an approach like this might work.

 

1) Create a library of cracked geo. ( maybe you can use a popnet sim with some propagation like behaviour. ( remember the popsim u showed me with VDBs to attach etc...maybe might be helpful)So you can make faster variations

2) So you have a fractured geometry. group the inner faces and reverse their normals so they look inside the goemetry( just the sides)

3) now you can push cracks further from each other with displace along normals working on these groups only( don`t forget to add the outer edge points also)

4) You can multiply displace along the normals scale value with some random attribute or maybe a fall off from epicenter so normals will pushed more at crack core and less towards the end

5) Use a fuse end of the line, so your cracked geo will fuse itself and fractures wont be visible, until they start getting away from eachother.

 

the issue;

 

even thou you can fuse and it will merge the points ,ice is refractive the inner fractures may be visible, but that`s another issue

[anim]

you can always post-sim delete inside polys based on proximity to each other and fuse the outside to get clean mesh even for transparent/refractive materials, then as soon as any piece shifts its position (cracks), the inside polys would naturally appear around it

 

EDIT: you'd need to do it in a Solver SOP to ensure that once the inside faces separate they are marked as cracked to avoid flickering if they fall back in proximity again by any chance

Edited May 31, 2015 by anim

[Diego A Grimaldi]

Yea I was thinking of trying that but I wasn't sure on how to approach it.

 

Would you mind putting a simple hip together to illustrate your method Tomas?

 

Thanks!

[Juraj]

I found this topic interesting so I decided to give it a try.

In atatchment you can see my attempt. I also tried to calculate proximity.

ice_crack_test.hipnc

[anim]

Yea I was thinking of trying that but I wasn't sure on how to approach it.

 

Would you mind putting a simple hip together to illustrate your method Tomas?

 

Thanks!

here is a simple example

ts_fuse_inside_faces_by_proximity.hip

Edited June 1, 2015 by anim

[Diego A Grimaldi]

Thanks for the golden file Tomas

 

Really appreciated!!