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Leo Chen
11-14-2015, 06:00 AM
I am trying to leran LightWave's Bullet effects.

And I have no idea how to destroy the box.
What's wrong?

caustix
11-14-2015, 06:50 AM
Unable to open the scene ... but did you fracture the box and assign to be a Parts Body?

Sensei
11-14-2015, 07:01 AM
You should use Fracture tool in Modeler.

Alternative method of cracking object I showed on video tutorial
https://www.youtube.com/watch?v=ud52wxYMygc

Leo Chen
11-14-2015, 07:18 AM
Unable to open the scene ... but did you fracture the box and assign to be a Parts Body?

Thank you,caustix.

Unable to open? how come?
I still can open it with LightWave Layout.

Leo Chen
11-14-2015, 07:21 AM
The layer 3 is the box to be broken down.

The layer 2 is the falling ball.

The layer 1 is the slope.

The layer 4 is the ground plane.

Leo Chen
11-14-2015, 07:23 AM
You should use Fracture tool in Modeler.

Alternative method of cracking object I showed on video tutorial
https://www.youtube.com/watch?v=ud52wxYMygc


Thank you, Sensei.

I apology for my bad English.

I mean I want to use the ball to crush the box to small pieces like "the RED Box in the following link".
https://www.youtube.com/watch?v=B9yX-KmJQ1Y&list=PLBscyc2_NuEDiXxnwjN7lG8vLYXlG6IQ0&index=30

Marander
11-14-2015, 07:38 AM
Hello Leo

Oh I see some guys already replied...

I quickly created a scene for you. In order for the object to break it needs geometry (for example with fracture). The box needs to to be a Part object in Dynamics. I attached a test scene.

Cheers, Marander

130995130996130997

130998

Sensei
11-14-2015, 07:55 AM
Cool animation Marander.
But I noticed that your box is starting disintegrating at frame 1, before even hitting ground object.
Set Mass Distribution to Solid or Surface, instead of Vertices, and it'll be fine.

Marander
11-14-2015, 08:04 AM
Thanks Sensei! Actually the box breaks when hitting the plank. Here's the video.

https://youtu.be/yLpB7iXqB-Y


Cool animation Marander.
But I noticed that your box is starting disintegrating at frame 1, before even hitting ground object.
Set Mass Distribution to Solid or Surface, instead of Vertices, and it'll be fine.

Sensei
11-14-2015, 08:07 AM
If I load your scene in v11.6.x (didn't tried 2015), parts are starting separating at frame 1.. :) Not too much, but enough to be visible.

Your original scene here:
131002

Parts flying completely separate :)
131001

After toggling Mass Distribution to Solid:
131000

And here we have little crack after hitting (as should be):
130999

Marander
11-14-2015, 08:15 AM
This is a bullet test I did couple of days ago

https://youtu.be/cyT41938xp4

131003

Marander
11-14-2015, 08:28 AM
If I load your scene in v11.6.x (didn't tried 2015), parts are starting separating at frame 1.. :) Not too much, but enough to be visible.

Thanks Sensei this is interesting because in 2015.3 it doesn't do that (see below). Good to know anyway!

I set the start position a bit higher on Y to see it.

131004 131005 131006

Edit: Here with the Bullet Panel open

131008 131009

caustix
11-14-2015, 12:21 PM
Isn't it the ball supposed to roll download and then hit the Box? That is a totally different story then ;-)

prometheus
11-14-2015, 12:22 PM
you can fracture directly in layout tool, less options..but itīs there, you just set desired cells to break etc..and it will fracture the box in layout, itīs int the fx tab, destroy,fracture.
turn off dynamics while doing so, and make the object a parts body, preferably set the mode of the pieces to convex for faster simulation. activate dynamics an click play.

MonroePoteet
11-14-2015, 01:53 PM
Here's a sample scene, with a variation on the scenario. I wanted the ball to push the box off the ramp, and have the box break apart when it hits the floor. To do that, I set the box convex-pieces Parts Object glue strength to 50%, but included an additive Y-distance to Object gradient, with the distance of .707m (half the cube's diagonal) from the GroundPlane object. This means when the cube is above .707m from the floor, the glue strength is 150%, so it holds together, but when it gets "within range", the glue drops to 50%.

I also used a gradient on the Linear and Rotational damping to try to get the parts to settle, although it looks like I should add an Envelope to ramp them up higher toward the end of the scene. Fracturing was done in modeler, using a cube with multiple segments in X,Y and Z that had been tripled to get a better fracture.

mTp

DrStrik9
11-14-2015, 03:39 PM
Alternative method of cracking object I showed on video tutorial
https://www.youtube.com/watch?v=ud52wxYMygc

Yes, this is labor-intensive, but a possible workaround nonetheless for the bugs (reported) in Modeler's Fracture. I still need to try Fracture in Layout, to see if it also yields the same errors as Fracture does in Modeler, with just about anything besides object primitives.

caustix
11-14-2015, 05:06 PM
The ball hits the box around frame 220. Box has been fractured in Modeler. The density for the ball and the glue strength for the fractured box were adjusted somewhat, but perhaps could work with the defaults too.

131017

Leo Chen
11-15-2015, 01:39 AM
Hello Leo

Oh I see some guys already replied...

I quickly created a scene for you. In order for the object to break it needs geometry (for example with fracture). The box needs to to be a Part object in Dynamics. I attached a test scene.

Cheers, Marander

130995130996130997

130998

Thank you, Marander.

You are totally right, my BOX is wrong.

But I have subdivided it...

BTW, How you make a Box like yours?
Use "Fractilize" command?
Do I need to do anything more on the box?

Leo Chen
11-15-2015, 01:53 AM
you can fracture directly in layout tool, less options..but itīs there, you just set desired cells to break etc..and it will fracture the box in layout, itīs int the fx tab, destroy,fracture.
turn off dynamics while doing so, and make the object a parts body, preferably set the mode of the pieces to convex for faster simulation. activate dynamics an click play.

Thank you, prometheus.

After re-turnning on the Dynamic, the Box disappears to nowhere!

- - - Updated - - -


Thanks Sensei! Actually the box breaks when hitting the plank. Here's the video.

https://youtu.be/yLpB7iXqB-Y


Great animation!

Leo Chen
11-15-2015, 02:00 AM
If I load your scene in v11.6.x (didn't tried 2015), parts are starting separating at frame 1.. :) Not too much, but enough to be visible.

Your original scene here:
131002

Parts flying completely separate :)
131001

After toggling Mass Distribution to Solid:
131000

And here we have little crack after hitting (as should be):
130999

Thank you for sharing the testing, Sensei.

BTW, I am using LightWave 3D 2015, the BulletSim.ZIP works perfect on my Mac mini.

- - - Updated - - -


Isn't it the ball supposed to roll download and then hit the Box? That is a totally different story then ;-)


Thank you,caustix.

MonroePoteet
11-15-2015, 04:20 AM
Thank you, Marander.

You are totally right, my BOX is wrong.

But I have subdivided it...

BTW, How you make a Box like yours?
Use "Fractilize" command?
Do I need to do anything more on the box?

When you subdivide a box, you still end up with a single geometry with more polygons, but they are still connected together. The Fracture button in Modeler under the Multiply tab will break up the geometry (in this case, a box) into multiple pieces, each piece being a separate geometry but fitted together to form the original. This multi-piece geometry is loaded into Layout, and given a "Parts Body" type in Bullet. This causes the Bullet simulation to treat each piece as a separately moveable geometry, allowing it to fracture into pieces.

Rather than using the Fracture button, you can break up the box into multiple pieces in various ways, such as the video Sensei referenced. Whatever method used, it must end up with an object that has multiple separate geometrical pieces.

For a simple scenario, do this:

1) In modeler, make a 1m cube
2) Press the Multiply=>Fracture button
2a) Clear the "Preserve Original" button, and press OK
3) Save this as "FracturedBox.lwo"
4) In Layout, load the FracturedBox object and move it to 3 meters high in the Y axis
5) With the FracturedBox selected, press the FX Tools=>Parts Body button
6) Press the Modeler Tools => Geometry => Ground Plane, and press OK with all default values
6a) or, you can load a ground plane object you've created separately
7) With the Ground Plane selected, press the FX Tools=>Static Body button
8) Press the Play button to run the simulation

If you see pieces of the fractured box falling through the ground plane (other than off the edges), you can increase the granularity of the Bullet simulation by increasing the FX Tools=>Item Properties=>World Tab=>Dynamics framerate to something like 600.

Hope this helps!

mTp

Marander
11-15-2015, 05:06 AM
Thanks Monroe, exactely! You were faster in answering

Leo, nevertheless here's the screenshots. The Fracture button is the last one on the left hand side. Please ignore the top menus since they are my customized ones.

131020 131021

Of course you're not limited to a box but with more complex objects you might have to do some manual cleanup. And if the fractured object doesn't look good before the impact, you could replace the clean object it at the frame of impact with the fractured one. For example in this test animation I did, I had to replace the glass object at the frame of impact:

https://www.youtube.com/watch?v=QudQaHzZvtg

Edit: And here's the crushed head :-)

https://youtu.be/EF9tkxZCsnw

Leo Chen
11-15-2015, 06:41 AM
If I load your scene in v11.6.x (didn't tried 2015), parts are starting separating at frame 1.. :) Not too much, but enough to be visible.

Your original scene here:
131002

Parts flying completely separate :)
131001

After toggling Mass Distribution to Solid:
131000

And here we have little crack after hitting (as should be):
130999

I have re-recreated a Box myself.
And just as you said, the box is starting separating at frame 1 on the slope!!!

But the "Mass Distribution" is default to "Solid".
Now, what I can do about it?
Increasing glue? friction? ...?

Leo Chen
11-15-2015, 06:45 AM
Thanks Monroe, exactely! You were faster in answering

Leo, nevertheless here's the screenshots. The Fracture button is the last one on the left hand side. Please ignore the top menus since they are my customized ones.

131020 131021

Of course you're not limited to a box but with more complex objects you might have to do some manual cleanup. And if the fractured object doesn't look good before the impact, you could replace the clean object it at the frame of impact with the fractured one. For example in this test animation I did, I had to replace the glass object at the frame of impact:

https://www.youtube.com/watch?v=QudQaHzZvtg

Edit: And here's the crushed head :-)

https://youtu.be/EF9tkxZCsnw

Thank you, Marander.

Leo Chen
11-15-2015, 06:47 AM
When you subdivide a box, you still end up with a single geometry with more polygons, but they are still connected together. The Fracture button in Modeler under the Multiply tab will break up the geometry (in this case, a box) into multiple pieces, each piece being a separate geometry but fitted together to form the original. This multi-piece geometry is loaded into Layout, and given a "Parts Body" type in Bullet. This causes the Bullet simulation to treat each piece as a separately moveable geometry, allowing it to fracture into pieces.

Rather than using the Fracture button, you can break up the box into multiple pieces in various ways, such as the video Sensei referenced. Whatever method used, it must end up with an object that has multiple separate geometrical pieces.

For a simple scenario, do this:

1) In modeler, make a 1m cube
2) Press the Multiply=>Fracture button
2a) Clear the "Preserve Original" button, and press OK
3) Save this as "FracturedBox.lwo"
4) In Layout, load the FracturedBox object and move it to 3 meters high in the Y axis
5) With the FracturedBox selected, press the FX Tools=>Parts Body button
6) Press the Modeler Tools => Geometry => Ground Plane, and press OK with all default values
6a) or, you can load a ground plane object you've created separately
7) With the Ground Plane selected, press the FX Tools=>Static Body button
8) Press the Play button to run the simulation

If you see pieces of the fractured box falling through the ground plane (other than off the edges), you can increase the granularity of the Bullet simulation by increasing the FX Tools=>Item Properties=>World Tab=>Dynamics framerate to something like 600.

Hope this helps!

mTp

Thank you, MonroePoteet.

Very clear and helpful.

MonroePoteet
11-15-2015, 07:47 AM
I have re-recreated a Box myself.
And just as you said, the box is starting separating at frame 1 on the slope!!!

But the "Mass Distribution" is default to "Solid".
Now, what I can do about it?
Increasing glue? friction? ...?

Getting specific results from Bullet requires playing with the various parameters quite a bit. In the case you want, the Box needs to have it's Item Properties => Activation tab => Initial Activation set to "Start Sleeping". This causes the Bullet simulation will leave it alone until some outside influence occurs, such as being hit by the Rigid Body Ball.

However, if you wanted the Box to be affected by gravity, you would need to adjust the Glue strength to hold it together better while allowing Bullet to simulate gravity on it. A technique which works well for impacts / collisions is to set the Glue strength to depend upon a Gradient with the Gradient set to be some Distance to the collision object.

I posted a more complex scene earlier in which the Ball pushes the Box off the Ramp to fracture on the floor / ground. This was accomplished by quite a number of adjustments in the various parameters available under the Box's Bullet Item Properties (FXTools => Item Properties, then select the Box), including a Gradient to control the Glue Strength based upon its distance to the ground / floor. Gradients are accessed under the (T) button.

One of the recommendations I can make in learning what the various Bullet parameters do is to make large adjustments to them. For example, if the default parameter value is 1%, try 100%, then 50%, and so forth, since the change in behavior may not be obvious with small changes.

Be sure to set your Frame back to zero or deactivate the simulation (by clearing the Enable Dynamics button) before making any changes, or Bullet will simulate up to the current frame. I normally leave dynamics enabled, but learned to press "f" and "0" to reset the frame to zero before making bullet changes.

mTp

DrStrik9
11-15-2015, 12:48 PM
On Fracture:

Fracture works like a miracle on very simple objects. But if you have a sub-D object, the docs tell you to freeze it before fracturing. Freezing many sub-D objects yields non-planer polys. In my experience so far, fracture (in both Modeler and Layout) on a frozen sub-D object produces MANY errors (crazy spikey polygons extending beyond the original object's volume), making the model useless, and extremely difficult to repair. Even tripling these non-planers is no help; the same errors occur. If you encounter this with a frozen sub-D object, then some version of Sensei's labor-intensive method is what you need to do instead -- that is, until they fix Fracture.

The problem:
https://youtu.be/75cfvR3S35w

The labor-intensive solution (so far):
https://www.youtube.com/watch?v=ud52wxYMygc

BeeVee
11-16-2015, 02:20 AM
I made one of the Constraints scenes for the 2015 content with a hinge constraint breaking and a box fracturing and played around with it some more. Try this out: HingeBreak (https://drive.google.com/file/d/0B3Ci2XdlK6C3UExNY2FLZ1JaZms/view?usp=sharing).

B
PS. The HingeBreak scene is the one in the 2015 content, the iterations thereafter are improvements and experiments. Try the first and last.

Leo Chen
11-22-2015, 04:05 AM
When you subdivide a box, you still end up with a single geometry with more polygons, but they are still connected together. The Fracture button in Modeler under the Multiply tab will break up the geometry (in this case, a box) into multiple pieces, each piece being a separate geometry but fitted together to form the original. This multi-piece geometry is loaded into Layout, and given a "Parts Body" type in Bullet. This causes the Bullet simulation to treat each piece as a separately moveable geometry, allowing it to fracture into pieces.

Rather than using the Fracture button, you can break up the box into multiple pieces in various ways, such as the video Sensei referenced. Whatever method used, it must end up with an object that has multiple separate geometrical pieces.

For a simple scenario, do this:

1) In modeler, make a 1m cube
2) Press the Multiply=>Fracture button
2a) Clear the "Preserve Original" button, and press OK
3) Save this as "FracturedBox.lwo"
4) In Layout, load the FracturedBox object and move it to 3 meters high in the Y axis
5) With the FracturedBox selected, press the FX Tools=>Parts Body button
6) Press the Modeler Tools => Geometry => Ground Plane, and press OK with all default values
6a) or, you can load a ground plane object you've created separately
7) With the Ground Plane selected, press the FX Tools=>Static Body button
8) Press the Play button to run the simulation

If you see pieces of the fractured box falling through the ground plane (other than off the edges), you can increase the granularity of the Bullet simulation by increasing the FX Tools=>Item Properties=>World Tab=>Dynamics framerate to something like 600.

Hope this helps!

mTp

Thank you,MonroePoteet.

I have tried for many times.
Sometimes it works, sometimes it does not work.
PS: I have no idea at all.

Sometimes it works but it creates "unwanted parts" attached to the model.
Example:
https://www.youtube.com/watch?v=g1fjnyQTPZk

Leo Chen
11-22-2015, 04:11 AM
I made one of the Constraints scenes for the 2015 content with a hinge constraint breaking and a box fracturing and played around with it some more. Try this out: HingeBreak (https://drive.google.com/file/d/0B3Ci2XdlK6C3UExNY2FLZ1JaZms/view?usp=sharing).

B
PS. The HingeBreak scene is the one in the 2015 content, the iterations thereafter are improvements and experiments. Try the first and last.

Thank you, BeeVee.

Leo Chen
11-22-2015, 04:16 AM
On Fracture:

Fracture works like a miracle on very simple objects. But if you have a sub-D object, the docs tell you to freeze it before fracturing. Freezing many sub-D objects yields non-planer polys. In my experience so far, fracture (in both Modeler and Layout) on a frozen sub-D object produces MANY errors (crazy spikey polygons extending beyond the original object's volume), making the model useless, and extremely difficult to repair. Even tripling these non-planers is no help; the same errors occur. If you encounter this with a frozen sub-D object, then some version of Sensei's labor-intensive method is what you need to do instead -- that is, until they fix Fracture.

The problem:
https://youtu.be/75cfvR3S35w

The labor-intensive solution (so far):
https://www.youtube.com/watch?v=ud52wxYMygc

Thank you, DrStrik9.

I will try again with "freeze tool".