Fracture tool

[kumpa]

hi!

I made tool for fracturing objects in houdini, it needs a bit of polish before release, but here are first results.

bun_0005Lg_Prog.rar

Edited May 13, 2008 by kumpa

[diula]

Looks great! Is that an OTL or an external software?

[CeeGee]

Greet tool, a was using some script i MAX, but this is great tool...

[Netvudu]

Good start! As you said it needs some polishing but it

Edited May 13, 2008 by Netvudu

[Zanozza]

Looks so primised for mine point of view!

[symek]

Just wait a few days, could be easier for you.. :bag:

[kumpa]

Here it is, looks like it works. As you will inspect the network you will see it is very simple (and messy). Ofc, if anything is unclear plz feel free to ask. I successfully fractured and simulated object with 1500+ parts on average computer.

And last but not least : No real bunnies were harmed during the production of this otl (Tnx Netvudu)

kfracture.rar

[symek]

Here it is, looks like it works. As you will inspect the network you will see it is very simple (and messy). Ofc, if anything is unclear plz feel free to ask. I successfully fractured and simulated object with 1500+ parts on average computer.

And last but not least : No real bunnies were harmed during the production of this otl (Tnx Netvudu)

Good stuff kumpa, smart one! Thanks for sharing it!

cheers,

sy.

[CeeGee]

Thanks...

[Korhon]

Playing around with it now, and it works perfectly!

Thanks alot!!!

[curveU]

hi kumpa, thanks a lot. One quick question, how could you handle the shader to make the object look like not fractured before it is broken?

EDIT: or we could only use a swtich node to switch it from an RBD obj to an RBD fracture obj at a certain frame?

Edited May 14, 2008 by curveU

[kumpa]

hi kumpa, thanks a lot. One quick question, how could you handle the shader to make the object look like not fractured before it is broken?

EDIT: or we could only use a swtich node to switch it from an RBD obj to an RBD fracture obj at a certain frame?

You just have to recalculate normals with cusp angle of 40 deg or so. Facet SOP is great way to do it.

Btw, i glad you like it .

[Rudinie]

Thank you Kumpa, this is working great and will be very usefull for me as a beginning Houdini user.

[iaiotom]

hi kumpa, im' interesting to develop a tool like that for maya ( i know i'm crazy ). Are you some papers that it explain the math algoriths for subdivide geometry like sphenoid voxel or others that you use in your fracture node?

Thx

iaiotom

Edited May 29, 2008 by iaiotom

[JDenker]

Hey kumpa,

do you ever tried to fracture heavy geometry with your kfracture tool?

I imported geometry from maya as fbx into houdini and tried to fracture it with your tool.

I am getting really odd results. I'm sitting here all alone at university and cannot figure this out.

I attached a file so you can better see whats going on.

before:

after:

What i was wondering too was(sorry for going OT because its not concerning your fracture tool!)

i also tried different others ways.

I extruded the geometry by .-1 and built some cutter geometry to cut holes into the mesh with cookie.

It worked perfectly at some test scenes with a cube and a sphere, which i did earlier tonight.

But now.. with this specific geometry, i have really problems with my cpu.

I built 8 holes into the geo. Its working pretty nicely but my computer here is totally slowing down on me.

I cannot even move the viewport in wire-frame mode.

Is there a more efficient solution maybe?

I'm also willing to post the hip files. both the tests and the one with the fracutures buddha if someone is interested in.

Thanks so much,

-J

Edited June 3, 2008 by JDenker

[kumpa]

hi !

can you please post .hip, my first guess is that geometry is not watertight. I will certanly take a look at it

cheers

k

[JDenker]

thanks for having a look kumpa.

here's the hip file

buddha_001.hip

Cheers

-J

[kumpa]

Short version: your geometry is not watertight.

Long version: First thing one should prior to applying any kind of boolean operation (which KFracture is all about) is to make sure that mesh that is about to be fractured consists of single piece of connected geometry that has no holes. Good way to ensure that is applying Divide SOP with Remove Shared Edges toggle on.

Twisted shape you will see is actually the covered hole but no geometry around. In simpler cases it would suffice to pipe both what is piped into Divide SOP and what comes out into Merge SOP and use Fuse SOP to weld everything together in order to produce fine watertight mesh. But if you take a closer look at some parts of this model, you may for instance discover that buda's scarf has no volume. In order for Boolean SOP to work, both object has to have some volume, otherwise the union between the object with volume and one without equals 0. Another perilous issue when using Boolean SOP are intersections. Those will surely produce unwanted results as intersecting surfaces fill have its normals filpped. Those areas can be found below the armpits,left foot and hands of this model.

Most obvious solution would be to go and edit problematic areas by hand. There are numerous others solution that would involve Ray SOP, IsoOffset SOP, but in particular case i would rely on manual editing of mesh.

Character modelers often share common defect i call quadophobia. It is state of mind that drives one to get rid of every non-quad polygon, no mater how many additional quads those actions will produce. When preparing geometry for fracturing it is even more imperative to make sure there are no problematic areas such as holes, surface intersections or separated shapes.

Hope it helps

k

[JDenker]

thanks a lot for the help and the fast reply kumpa!

cheers

-J

[ranxerox]

hi all, I've tried out the KFracture tool and it works great ! Now I am trying to use the debris tool in conjunction with it, but the debris tool seems to require a group called "inside" in order to function properly. I'm somewhat of a noob in houdini. Any ideas on how to accomplish this ?

thanks

-ranxx

You just have to recalculate normals with cusp angle of 40 deg or so. Facet SOP is great way to do it.

Btw, i glad you like it .