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wateryfield

how to make voronoifracture much more complicated

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Hey

I've been playing with a basic voronoifracture.

It has lots of detail inside when tick the interior detail.

But it is a way to make the surface much more complicated.

The surface edges is not as well as inside.

Is it a parameter to change?

Look at the thumbnail.how can i make like this.

Poor english,sorry

THANKS

post-9982-0-17481800-1375203065_thumb.jp

post-9982-0-02464000-1375203071_thumb.jp

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The easiest way is to make lots of smaller voronoi chunks and then group them together with the custer pieces tab to group them together.

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The easiest way is to make lots of smaller voronoi chunks and then group them together with the custer pieces tab to group them together.

THANKS……I have try it brfore, but it is not i really want.

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The easiest way is to make lots of smaller voronoi chunks and then group them together with the custer pieces tab to group them together.

hmmm, that certainly doesn't seem very efficient ;)

I think the solution is more custom than one size fits all. A lot of it depends on what your fracturing. for a basic wall, I might try something like this

I forget who it was, but someone on the forum created a really nice shatter tool that had really nice edge details on both flat and round surfaces. I think it's availalble on orbolt somewhere ;)

fracture.hip

Edited by substep

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One idea is to use a divide and generate additional geometry via the bricker, then apply noise to P in a planar fashion.

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hmmm, that certainly doesn't seem very efficient ;)

I think the solution is more custom than one size fits all. A lot of it depends on what your fracturing. for a basic wall, I might try something like this

I forget who it was, but someone on the forum created a really nice shatter tool that had really nice edge details on both flat and round surfaces. I think it's availalble on orbolt somewhere ;)

THANKS. Jorge

Your attached file is helpful and also have nice detail.

The shatter tool i will have a look.

THANKS again.

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Just be careful with Bullet. At it's defaults for performance it expects your geometry to be convex. This means the object should not be self-shadowing. That's why most voronoi fracture set-ups create boulder-esque like chunks and not more interesting concave shapes.

You can rely on bullet to auto-glue pieces that share transforms to create interesting shapes or construct geometry constraint networks to hold complex shapes in place during the simulation. This approach relies on shattering chunks and then shattering fine chunks off the larger chunks as well and then glue the finer chunks to the bigger chunks to get interesting shapes.

In general, when testing out new shatter set-ups, bring in your shattered objects in to a Bullet RBD sim and turn on the collision geometry to see how the collision geometry is being constructed. You can easily see with concave chunks that the collision geometry skips right over the concave parts. The issue arises when you shatter say a concrete slab and pieces are very tight together and you have these concave areas. Bullet sees these pieces are interpenetrating and when you dissolve the glue constraints, pieces can tend to fly off.

Edited by old school

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In general, when testing out new shatter set-ups, bring in your shattered objects in to a Bullet RBD sim and turn on the collision geometry to see how the collision geometry is being constructed. You can easily see with concave chunks that the collision geometry skips right over the concave parts. The issue arises when you shatter say a concrete slab and pieces are very tight together and you have these concave areas. Bullet sees these pieces are interpenetrating and when you dissolve the glue constraints, pieces can tend to fly off.

In Houdini 12.5, the Bullet Solver is able to detect objects that are initially interpenetrating and prevent the Bullet engine from causing those pieces to fly apart, so concave chunks shouldn't cause problems anymore.

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In Houdini 12.5, the Bullet Solver is able to detect objects that are initially interpenetrating and prevent the Bullet engine from causing those pieces to fly apart, so concave chunks shouldn't cause problems anymore.

Are you sure? because it still pops up for me and I have to take care of those concace chuncks in order to control the popping. Maybe it only works for the pieces penetrating others within the fractured object DOP. If it is initially penetrating a static object(my case) even if it is included in the glue net the popping remains. Nevertheless I wouldn't count 100% that it is solved. Correct me if I am wrong

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Are you sure? because it still pops up for me and I have to take care of those concace chuncks in order to control the popping. Maybe it only works for the pieces penetrating others within the fractured object DOP. If it is initially penetrating a static object(my case) even if it is included in the glue net the popping remains. Nevertheless I wouldn't count 100% that it is solved. Correct me if I am wrong

If there is any popping then there's a bug - if you have an example file that demonstrates that issue then I can take a look at it.

I've attached a simple example made in 12.5.469 that contains a static object and a regular RBD object which interpenetrate, and there isn't any popping.

interpenetrating.hip

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The popping isn't the issue. It's the fact that the Bullet collision representation is convex regardless of your input geometry. The popping occurs because the Bullet collision geometry for each piece is inter-penetrating. Even if you ease this in, the pieces will separate out and collisions will be incorrect. If this is ok, sure. If you need accuracy, nope.

Pass in a concave geometry object in to Bullet and with the default Polygons As Convex Hulls option on (for performance), display the collision geometry and you will see that the concave areas are completely passed over. Sure you can disable this option but you won't be able to run up the simulation numbers as it won't be nearly as efficient.

post-371-0-84842500-1375373282_thumb.jpg

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If there is any popping then there's a bug - if you have an example file that demonstrates that issue then I can take a look at it.

I've attached a simple example made in 12.5.469 that contains a static object and a regular RBD object which interpenetrate, and there isn't any popping.

I am afraid I can't send a hip since it is for production. My problem is that my scene is a bit more complex to your test scene (thx for sharing). And yes the popping might not start from the frame I let loose my glue-net. But rather if the pieces are still next to eachother and the static object is still moving. I will put up an example if I have time.

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