Voronoi Fracture generating bad geometry with Packed Primitives

[moebelhaus]

Hey guys,

 

this is my very first post, about one of my very first tries in houdini... So I am overlooking something OR (and that's much more probable) I dont get it:

 

I am trying to destroy a building, prefractured via "voronoi fracture", packed into packed primitives via "assemble", brought into DOPs via "RBD Packed Object", pieces glued together via "Constraint Network". Everything works quite fine BUT I am also using Voronoi Fracturing within DOPs to dynamically break the geo further apart once it is being hit by the impacting sphere.

 

Now the problem is that the dynamically broken fragments generated inside DOPs are completely messed up. In the screenshot below you can see that the newly created inside faces (grey)are immediately detached from the new chunks (teal/blue). And I cant figure out why.

 

For kicks I tried the whole thing not using "RBD Packed Object" but rather "RBD Fractured Object", which was infinitely slower, but at least worked. I would reeeealllly love to use packed primitives though, and with a simple Torus, that workflow does actually work. hm.

 

So the questions in my head right now are: Is it the way I treat (or not treat) the incoming OBJ? Is it the scale of things? Is it the crazy impulse forces? Is it the fracture pointcloud scale?

 

ODFORCE is the place to ask for help, too many smart people out there!!! Thanks in advance to everyone having a look at this.

 

Thanks guys!!

 

 

 

 

odforce_voronoi_bad_geo.zip

Edited July 25, 2014 by moebelhaus

[wateryfield]

Hey guys,

 

this is my very first post, about one of my very first tries in houdini... So I am overlooking something OR (and that's much more probable) I dont get it:

 

I am trying to destroy a building, prefractured via "voronoi fracture", packed into packed primitives via "assemble", brought into DOPs via "RBD Packed Object", pieces glued together via "Constraint Network". Everything works quite fine BUT I am also using Voronoi Fracturing within DOPs to dynamically break the geo further apart once it is being hit by the impacting sphere.

 

Now the problem is that the dynamically broken fragments generated inside DOPs are completely messed up. In the screenshot below you can see that the newly created inside faces (grey)are immediately detached from the new chunks (teal/blue). And I cant figure out why.

 

For kicks I tried the whole thing not using "RBD Packed Object" but rather "RBD Fractured Object", which was infinitely slower, but at least worked. I would reeeealllly love to use packed primitives though, and with a simple Torus, that workflow does actually work. hm.

 

So the questions in my head right now are: Is it the way I treat (or not treat) the incoming OBJ? Is it the scale of things? Is it the crazy impulse forces? Is it the fracture pointcloud scale?

 

ODFORCE is the place to ask for help, too many smart people out there!!! Thanks in advance to everyone having a look at this.

 

Thanks guys!!

 

egyptianTemple_v005.0071.jpg

 

odforce_voronoi_bad_geo_snip.jpg

It seems the packed object can't apply voronoi fracture configure object sop in DOP.

My fault,This DOP can be applied to any active RBD Object or RBD Packed Object

But i can't figure out what's the problem it works not good enough.

 

But you can unpacked the packed object.

Or fracture the object first then turn into DOP.

odforce_egyptianTemple_cgfx_destruction_v005.bad_voronoi_1.hipnc

Edited July 26, 2014 by wateryfield

[moebelhaus]

hey wateryfield, thanks so much for your quick reply! and the .hip of course. That actually solves the problem, which is awesome. And yet, it seems so expensive when it comes to sim-times, now that we are not dealing with packed geo anymore.

 

Interestingly, a super-simple torus situation actually gives really nice results with dynamic fracturing using packed primitives. So somehow, it does seem to work..... just not with my egyptian temple scenario :/

 

 

check this out... super simple scene.

 

 

odforce_voronoi_dynamic_packed.hipnc

Edited July 26, 2014 by moebelhaus

[moebelhaus]

interestingly, after going through everything again, I found the cause for the f*cked *p geo-pieces.... which makes it work with packed prims also (praise the lord).

 

when i am initially fracturing my building still in SOPs, in the "Voronoi Fracture" Node I had checked 'Keep Internal Attributes' checked in the 'Attributes'-tab. Which messed it all up, once it started dynamically fracturing the geo in DOPs. UNchecking this makes it work smoothly again.

 

Since I am new to Houdini, this doesnt immediately make sense to me, but I guess since DOPs is pulling in the source SOP recursively at every timestep and new geo is being created in DOPs, the source attributes from the original SOP-Voronoi-Fracture might overwrite the attributes of the new pieces being created. Hence the disconnected geometries that don't belong to any proper piece anymore...? Does this sound right? I am just trying to wrap my head around the whole "SOP>DOP>and back" transfer process here.... hm hm hm

 

 

hip is below:

odforce_egyptianTemple_cgfx_destruction_v005.bad_voronoi_2.hipnc

[wateryfield]

interestingly, after going through everything again, I found the cause for the f*cked *p geo-pieces.... which makes it work with packed prims also (praise the lord).

 

when i am initially fracturing my building still in SOPs, in the "Voronoi Fracture" Node I had checked 'Keep Internal Attributes' checked in the 'Attributes'-tab. Which messed it all up, once it started dynamically fracturing the geo in DOPs. UNchecking this makes it work smoothly again.

 

Since I am new to Houdini, this doesnt immediately make sense to me, but I guess since DOPs is pulling in the source SOP recursively at every timestep and new geo is being created in DOPs, the source attributes from the original SOP-Voronoi-Fracture might overwrite the attributes of the new pieces being created. Hence the disconnected geometries that don't belong to any proper piece anymore...? Does this sound right? I am just trying to wrap my head around the whole "SOP>DOP>and back" transfer process here.... hm hm hm

 

odforce_voronoifracture_keepIntAttribs_snip.jpg

 

hip is below:

I think you are right.

The name attribute tell packed object which piece it belong to. If you turn keep internal attributes on, there is another attribute called Primitive Piece same as name attribute keep the piece right position.

But after dynamic fracture, the Primitive Piece attribute will be not right.

 

 

But i don't like voronoi fracture configure object at all. The collision jitter too much.

Maybe you can simulation a big piece RBD first, then use impact point to create the little piece fracture.