[Custom Build] Blender Fracture Modifier

(Kai Kostack) #1701

Some attempts to make plane crash simulations more realistic using BCB + FM:

(wolfie138) #1702

can you give me some more pointers please? i’m trying to adapt that second file you provided ~ i’m not sure of the significance of the metaball remesh etc so i thought i’d just use a particle system on the cube to fire at the wall. i’ve given the particle a Rigid Body and set the emitter as a brush and paint source as the particles, but when they hit the wall theyjust seem to be making more fractures as the impact point, they’re not demolishing the wall as yours did. i took the Dissolve option off the wall, which was making it repair itself but that didn’t help the actual destruction. the bullets are a brush as you suggested above.

(scorpion81) #1703

The remesh metaball modifier is just one way to convert particles into a mesh for this use case. Alternatively you could also use a particle instance modifier on say, an icosphere. Pick the cube and its particlesystem there (make sure the sphere is at (0, 0, 0)).

The most important part is the collision modifier on the wall, which lets the particles bounce off. Those bouncing particles will take “their” instances with them, so effectively it only “looks like” that the wall affects the rigidbody spheres. In fact, the spheres alltogether form ONE rigidbody. It is also crucial here to set the rigidbody shape to Mesh and to Final + Deforming (an FM only option). So as the particles bounce, they also will deform the rigidbody, and it will update its mesh.

Furthermore the rigidbody is kinematic so it stays in place, and a trigger to affect the shards of the wall. The wall shards will be activated and will collapse, thus altering the collision shape for the particles, which will now as the wall goes down, not bounce off any more. Thus the rigidbody shape will update to reflect this and so on.
The dynamic paint brush is only for the purpose of letting the smoke and dust / debris emit where it touches its canvas, aka the wall. That in fact is also only possible in FM build due to a hack in the particle system which allows to respond to dynamically changing density vertexgroups over simulation time.

(Shunke) #1704

Where can I find tutorials ( or documentation) for Fracture Helper Addon ?
I want to learn all the features provided by the addon and test smoke and debris,
but I cannot find any documentation or tutorial.


(wolfie138) #1705

Hmmm…i’ve added the particle system to my emitter but when they hit the wall it just remeshes the wall and none of the physics takes place, have i mistakenly changed something? [i turned off the Dissolve again to prevent the wall repairing]

(JTA) #1706

I have not put out docs on the helper addon yet. I have some I am working on that will be out in the next month or so.

Currently FM development is in the highly experimental stage and we encourage users to experiment with us. We know that is time consuming but it is very rewarding. You just have to invest the time to learn the tool and get results you like in general.

More specifically, Scorp’s inline tool tips are awesome and very helpful so just mouse over for those in both the addon and the properties panels.

You can also check back through this thread for some good tips and workflows.

For addon video tutorials check Dennis’ work on blenderphysics.com and his Youtube channel. He does most of our tutorial videos. He has one for getting started. I don’t recall how much it covers the helper addon though. He has more tutorials in the works.

Juan from Bone-Studio has some Youtube tutorial videos up also for FM.

You can also ask specific questions here. The community is growing so sometimes users will also provide some really good advice here. Just make sure you experiment first so you can form detailed questions and not just ask how to do things in general if you want very specific results.

The helper addon just automates and speeds up the workflow. The smoke and particles interaction is mostly standard blender smoke and particles workflows.

Good luck and keep us posted.

Fracture ON!

(scorpion81) #1707

I have a potentially fixed file here :

Important was that the bullet object needs to have a particle instance modifier with the gun object and its particlesystem. This way the bullet objects mesh is altered to match the particles, but it remains a mesh (and is no dupli object, which cant be turned into a rigidbody) Then use mesh final deforming rigidbody shape.
Tip: if the physics seems off, try the “Visualize Physics” checkbox in scene -> rigidbodyworld.
Inside the blend file there are also a few more hints.

(wolfie138) #1708

Damn, that’s incredible!
thank you very much for taking the time to help me w/ this :slight_smile:

(wolfie138) #1709

How do you add the debris system? i’m playing on another file to save messing w/ the example you gave me, and when i select my wall then click the button nothing happens. the smoke gives me a warning that i need a Domain but i’m not seeing any message regarding the Debris.

(scorpion81) #1710

Does the wall have an FM on it (and is it already executed ?) if that doesnt work, please link the other file here too if possible.

(scorpion81) #1711

just a test with a cleaned up version of the brick mesh, with brick fracture + dynamic fracture + bevel + dupli fracture source in FM 2.8. Note this is all WIP still and not ready yet.

(wolfie138) #1712

Looks amazing.
Not sure what happened about the Debris, i re-opened my file, tried again and it created one no problem.
could you give a quick explanation of the Dust settings please? i can’t figure out where the materials come from - the particle system [in your latest file] has it listed in the Render panel as “Details.001”, and it’s greyed out. There’s a Smoke Domain material, but it’s white and i’m seeing something grey. had a fiddle, changing to Cycles and setting up a proper smoke material using the density attribute etc but didn’t seem to affect anything.

(scorpion81) #1713

Hmm that “Details.001” Material is the first material in the wall.000 object, so it has been in your original file already. Seems it is a cycles material with nodes. In the Dust particle system, it is set as “Render” material probably by default, just because it is the first one.

And it is greyed out because this particle system uses a dupli group. E.g. with different render settings it is not greyed out.

Hmm probably i didnt switch to cycles “before” using smoke on the addon (which in turn calls the quick smoke operator, and that one creates materials depending on what render engine you selected before.
Probably I had blender internal active then.

You could remove the domain and all other remainders of the addon smoke setup, switch to cycles and re-add the smoke.

(Shunke) #1714

Thanks for the reply. I cannot wait for FM getting complete and merged into Blender 2.8.

(wolfie138) #1715

Ok. In Cycles, i removed the domain, all the Dust and Debris objects and the systems from the wall.
readded the Debris - the DebrisObjects all have one material, the wall inner one, but in the wall’s particle settings the Render tab shows the wall Outer on, and it’s greyed out. It was first in the stack of the wall’s materials as you said - i’ve noticed you can use the up and down arrows to shift the materials up and down the stack and it amends the particle Render setting accordingly, but it’s still greyed out.

Created a Smoke Domain, added Dust to the wall. That particle system is as above, shows the first material in the stack and is greyed out. the Domain has no materials on it yet. in your test file the domain had “Smoke Domain Material” ~ for Cycles, i assume i’ll have to create a material as i usually do for smoke [using the density Attribute and the Volume Scatter/Volume Absorbtion nodes etc] but i’m not sure how the particles will reference this.
Just as a test i deleted the Dust modifier, added a smoke material as above, then re-added Dust to the wall, but i got the same results.

edit - another thing i’ve noticed, is that i sometimes end up with multiple Inner materials on the wall - i assume this is happening when i click the Execute button, but it doesn’t seem to be happening all the time [i’ve been clicking it a lot, tryng to get the right look etc]. just noticed it so i’ll keep a look out on further tests to see if i can find the cause.

(mcbeth) #1716

have a question about particles in regards to bullets, can particles be made to “die” or deflect on impact or after an “amount” of penetration, especially if you want your fractured object to remain mostly structurally resilient.

also is it possible to add custom collision effects dynamically like the smoke or dust e.g. a comic ricochet object e.g. see red circle

also might it be possible blender fracture to simulate character damage and produce squib like effects through the dust and smoke stuff

currently working on the action stuff in my little action short and used fracture builds to help with the destruction stuff thanks in advance

(wolfie138) #1717

I’ve been trying to get a bit more elaborate w/ my wall, and have created one w/ more details - window holes and brick trim etc. The problem i’m having is my trigger hits the wall as i want, but it’s leaving fragments in mid-air:

is there anyway of getting gravity/active Rigid Body physics to work on unconnected pieces like this? i played w/ keyframing the “triggered” and “animated” properties, but the lower part of my wall was put into a vertex group to make use of the Passive Vertex Group and when i remove the Triggered and Animated it seems to loose that as well, and the whole wall collapses.

(scorpion81) #1718

Hi :slight_smile:
Well i am working on a way to convert dupli objects, e.g. from particles to individual rigidbodies during the FM simulation, but thats a work in progress on the new FM 2.8 codebase. I would need to see if its possible to backport the “duplifracturing” as i call it to 2.79x FM.

Until then you can only use an object with a particle system, and another object using a particle instance modifier which uses the former object as “reference”. Then you can let the object which is supposed to be destroyed get a collision modifier after the FM, so the particles will bounce off the mesh. Then, you can make the particle instance modifier object a mesh final deforming rigidbody, so the physics shape will match the particle instances (which are controlled by the bouncing particles).

This “deforming” rigidbody can be used as trigger for example. The particles could be killed on collision, thus the instance should disappear and being removed from the rigidbody too. To restrict the destruction on the triggered object, one could maybe place a static, invisible collision object inside it / at the desired “penetration depth”.

You can furthermore add custom debris and / or dust objects as well. The addon creates only some default objects to be used with the particle systems, but those should be exchangeable. But those will be attached to all active debris particles. Hmm. maybe you would need to shorten the life time of the debris particlesystem to a couple of frames and / or reduce the amount of total particles to display some of those comic objects you mentioned.

character damage, hmm. maybe you would need to prefacture your character mesh, make it animated / triggered. and let colliding objects trigger those. Dynamic fracturing would have been an option too, but in 2.79 this is very badly implemented, unfortunately. The newer FM 2.8 design adressed that to some extent and will allow better dynamic fracturing, as in fracturing while the simulation runs, based on impact points.

“squiblike effects” should be in theory possible as any other trigger based smoke and dust effects with the addon. (by adding inner smoke and dust thru the addon)

(scorpion81) #1719

Hmm i think clusters and the “activate broken” setting are your friends here. You connect your shards with constraints and specify a count of clusters, say 10 or 20. Then enable “activate broken” and some cluster breaking rules like an low angle and percentage about 75-90%. Means if x percent of the connections are broken, the rest will be broken (and activated) in this case, too.

This means further if a couple of clusters break according to the rules, activate broken should also activate nearby constraint partners and clusters relative to the hit shards. You may need to experiment a bit with the breaking values too to get the desired effect.

It may also help to have “longer” connections which are not only neighboring shards, but also shards behind the direct neighbors, in case the activation doesnt propagate as far as desired.

Let me show you an example:

This one had too “short” constraints, as in search radius was only 1. Activation didnt propagate far enough.

This one has longer constraints, but at the same moment it doesnt seem to work as well. But the breaking pattern already looks more convincing… lets wait a couple of more frames…

and boom! there you can see activation propagates up all the way to the roof and the floors above the damaged one will come down too.

Example blend: skyscraper1.blend (2.6 MB)

(mcbeth) #1720

if you are willing to do that, it would be very useful since this is a blender internal project which isn’t in 2.8, if I remember correctly, I have to be just about the only blender user to have not even downloaded 2.8 as yet. It took a very long time to come up with that “comic like” look and still isn’t completely where I wanted it to be and not willing to start over with this

would it be possible to provide a simple example of this to follow along,still more or less in the learning chase, will try to figure it out though

I had the idea of duplicating and solidifying the chunks of mesh that would receive hits, I remember seeing a tearing example for FM…if I’m not mistaken …is that supported in 2.79 again if I’m not mistaken

cool will look into it