started to play with bullet but ...

[johnl3d]

I thought I'd tinker with new bullet feature in 19 but getting lost...wanted to drop an sphere onto a plate and have the plate break but cannot get plate to break when hit by bullet any suggestions welcome on how to set up that part

 

 

 

[Rodney]

You are able to get Bullet to simulate right? It's just not breaking?

 

Two things come to mind but much will depend on what is in your project.

For instance, if objects are passing through each other... consider the density of the mesh.

 

Settings for weight can be important.

For instance, in a dense mesh built with Rebuild Explode plugin I weighted some groups very heavy but left some at default (low setting).

What this does is create an imbalance so that when impact occurs the heavier parts keep moving while the others stop... this then leads to the breaking.

 

*If* the simulation is just not running at all, remember that at least one object in the project needs to have a Bullet Body constraint applied to it.

I would apply a Bullet Body constraint to each and then assign a lighter weight to the plate.

 

At this point I think we need more info or a project file to examine.

[Rodney]

Oooo.... you can try having one of the objects have a weight of zero.

The object with the weight will fall into/through the other object.

Have the other/falling object have a weight of 500.

 

I'm sure I'm not doing this right but in trying to recreate what I think you have set up I found that having one part of the explode object set to zero weight helped to keep the object in place.until it was hit. Thereafter everything broke apart. The downside of this is that once hit all the pieces *except* the one with weight of zero fall to the ground. A workaround for that would be to add a part to the object that can be made transparent. That transparent part then stays in place while the rest of the object falls away.

 

Like I said, I'm probably doing this wrong on my end.

 

I've posted some examples of two objects crashing together and then breaking in the Alpha/Beta forum so I know it's possible to keep the object in place.

Perhaps it just requires a keyframe.

[Rodney]

Here's a project file with two Chors.

The first is the pre-simmed setup and the second is the results of running the simulation.

 

Assuming I'm not way off track... there may be some settings that help get things set up on your end.

Ball and Plate.prj

[Rodney]

Here's a try with four (almost stacked) plates.

(I like using the new Duplicate option via Right Click in the Chor. Duplicate and then move slightly to new postion... Duplicate. Ditto. Duplicate. Ditto. etc.)

 

Note that my creation of the plates by lathing with 5 cross sections has limited the breaking points of the plate.

Lathing with more cross sections or building the plate some other way would result in better breaking.

 

Same drill. One Chor is pre-simulation. The other is results.

 

 

 

 

Ball and 4 Plates.prj

[johnl3d]

Thanks Rodney I will investigate your explaination/tutorials when I'm on the computer later..(on chromebook now) and post results or further questions

[johnl3d]

Cannot see what I am doing wrong so attaching basic project with bullet and target that I want broken

 

 

Thanks for any help you can give me

 

nocrash.prj

[Rodney]

John,

You forgot to embed the models.

A:M states that 2 coins and 2 spheres are missing which I suspect might be 2 instances of the same coin and sphere.

The sphere is easy enough to replace but the coin...

 

I don't think I can properly assess the project if one of the models (the coin) was created with the Explode Rebuild plugin.

I'll go into a holding pattern pending your response.

 

Edit: From what I can tell it appears you have not made the Coin (the explode rebuild model) a Bullet Body.

To do that: Right Click on the Model's listing in the PWS, Add Constraint, Bullet Body.

[johnl3d]

nocrashall.prj

 

 

this should include both models ...sorry to bother you but this looks like something I could use or at least tinker withnocrashall.prj

 

 

[johnl3d]

Will have to work on this as when I did that the explode rebuild exploded on first frame....

[Rodney]

Yes, it seems that the sections of the explode rebuild model are reacting too quickly.

I haven't been able to find an ideal setting to change to bring it down to something reasonable.

BUT... at least it's breaking.

 

I'm wondering if there might be a bug in the Bullet Joint Setting.

Although it is set to 1 for a value the main setting is OFF and that cannot be changed.

That seems odd to me.

 

I need to review the Bullet Physics documentation Steffen has posted.

If you haven't done so already I recommend playing with the project files he posted.

That angular motor is very cool... and I've played a little with that. Automated motor in A:M... that's sure to be useful!

[johnl3d]

Thanks for all your time I will have to "tinker" with this later and play with the sample files