Welcome to breaking up a model using particles.
So falling apart.
Unfortunately blender needs to be told how to break something up it's not going to do it automatically
which often means we need to create geometry to reflect the part of the mod or parts that we want to
fall apart or snap or break or dissolve or what sort of effect we want from Blender.
Now there are a couple of ways of doing that now manually.
Now this is often the most and time consuming.
And it is not advised we've constructed the wall manually that's one way of building up something in
order to bash parts.
Obviously if that was a whole building that would be quite time consuming to model each individual break.
Not only that but it would take a lot of computational time as well.
That's a simple model the actual brick wall that we've got so far.
But if it was more complicated it would just not be advisable to go down that route.
Now it may actually give you the most accurate model or the most control over your model as well.
But there's an argument to say when you don't need to use the physics Well let's not use it and let's
just use the physics on the bits we need to do and perhaps annamay the other bits otherwise.
Generally anything to do with falling taking something apart breaking apart is actually going to use
the particle system to help break up a model.
And we'll explore that in a few moments.
Now physics can then be applied to the pieces themselves that we've generated and we're not going to
do that in this particular lecture but we do that in a future one very soon or the particle system itself
and once the particle system starts behaving physically well then we can have lots of fun with it now
affecting the particles themselves.
Now the way that particles are affected by the physics is controlled in the particle system tab is not
controlled in the physics itself.
In fact the mesh itself the one we're going to take part in a moment doesn't have to have any physics
applied to it at all.
Now other objects that interact with those particles do need physics.
So we're going to have a look at the particle settings in more detail and we're also going to look at
the collision physics data as well.
So let's hop straight on over and play with particles and exploding things in blender.
So were over in blender here.
And let's start playing with this cube.
Now if we're destroying anything we want it to break into multiple pieces.
And like we have done before let's give this cube some pieces for it to break into.
In this case it's going to be quite regular.
I'm literally going to go to a subdivision surface modifier.
So we got here and we're going to increase the number of subdivisions.
Now I'm not going to apply the modifier at the moment we shouldn't have to do that unless it's absolutely
necessary because I'm just going to use a particle effect to move things out now in the future he wanted
to make this particular or the bits that blow out individual objects.
Now that's where you would actually have to apply servais are separate objects.
Okay so we've got a ball here.
Okay.
Brilliant.
Let's add a something for particles to collide with like a plane.
And I'm just going to scale that up.
Okay so now that's scaled up let's add the particles in so selecting the US is a cube that's let's call
it ball.
So selecting the ball I'm going to add a particle system to it.
And I'm not going to do anything else.
I'm just going to press play so often.
And we can see what happens so these particles are being generated.
And if we have a look at the particle settings themselves we can see what's going on.
There are a thousand particles being generated between frame 1 and two hundred.
And they've got a life of 50.
So we're not going to see any of these die within this particular scene that we've got set up at the
moment.
But if I set the end value to let's say one hundred fifty we're going to see that some of these are
falling.
Here we go.
They just die at this point which is at 50 frames.
They just start disappearing now in a moment when we actually attach that and make this sphere explode
while that all mean is basically it pauses it no longer has a particle.
So that part of the mesh just stops doing anything really.
Now one of the things that you can do to make sure this is optimal is have a look at the number of faces.
So we've got our our selected here we have a look at the number of faces it has we can see it's three
hundred and eighty five.
So the number of pieces we can physically break this ball into is three hundred eighty five and no more
so we don't need any more on this emissions value than three hundred and eighty five.
It would just be a waste.
The other thing we can do here is increase the lifetime so it actually lasts at least as long as the
scene.
Now the other thing that we can do here is have a look at this start value an end value.
Now I'm going to increase the start value to frain 10.
So no particles will exist until frame 10 but they will still last 200.
So some of these 385 won't actually exist in this particular scene that we've got set up because it
only gets to frame one hundred fifty.
Now if I set the end of the particle generation down to 10 that means that all of those three hundred
eighty five individual particles are generated instantaneously at frame 10.
And I'm going to leave it like that for the moment because that's more of an explosion.
Something else would be more of a houseboat in evaporation.
So we've got a couple of other options down here but before we start hearing with those.
You may notice that the actual particles themselves are falling through the frame.
Now this plane that we've got set up here we don't want that to happen.
We want them to hit this plane.
So let's go ahead and look at the physics now.
Ordinarily you'd add a rigid body to this for things to collide with but it's not a rigid body these
are particles.
So we need to select collision instead.
Now when we select collision you can see that some of these particles are going to switch back to the
spheres so we can see them.
All of these particles are bouncing in and around and they're not really being dampened they're just
continuously bouncing which seems a little bit unrealistic.
Usually they would come to a settling point.
So going back to the plane itself that we've added the colation to notice with not mucked around with
any physics to do with the actual particles themselves we don't have to do that.
What we do have to do with however is play about with the collision settings.
So if we have a closer look we can see that the whole left hand side is all devoted to particles wiegert
particle Perman ability stickiness.
We can kill the particles.
Now that just basically means as soon as they strike that surface.
Stop and do nothing else but that can cause other issues as well but it's a great starting point.
Now we've got dampening and friction.
So let's play with each one individually permeability.
Well the higher that is the more of these particles that will pass through.
And that's a great way of if something impacts something else if you want it to basically vaporize and
disappear so there's less the brewery or something along those lines stickiness and dampening a very
very similar in what they do.
So the stickiness is as you can probably guess how sticky the surfaces dampening does dampen the bouncing
and the movement of particular particles.
So we can see it's coming to a rest.
But when they eventually come to a rest we'll look at that they're still sliding away and this is where
the friction comes in.
So we can increase the friction factor and play with these until we're happy so we can have a high damp
and low friction and then there we go.
They come to settle down.
Now we're not actually seeing anything happen at the moment with this sphere so let's go ahead and do
that now we've set up the particles.
Let's actually have the sphere explode and see what happens.
So go to the modifier tab on this sphere or the ball that we've got set up and I'm going to add in explode
modifier.
And hopefully I'm okay.
So this is too long to set it back to 100 frames the end 100.
Okay.
That looks pretty good.
I like that it's a bit too bouncy but will leave it as it is for the moment.
Plenty of room for improvement.
Now look at that the particles themselves are all rigid and quite uniform.
That's not something we want so we can go back to the particle settings and change things.
So let's go to the particle settings.
You will also notice by the way that this is you know these bits as dug into the surface there's nothing
we can do about that at the moment.
They'd have to be individual objects to not dig into the surface like this because it literally around
each of the particles themselves the faces that were on that ball and now sort of.
So centred around.
So let's have a look at the other settings.
So we've dealt with emission so I'm going to turn that were not off.
I'm just going to hide it by clicking emission.
The little arrow next to it.
Velocity valve that's a great one as you can probably guess with velocity.
It gives us a speed at which this thing's going to explode.
So while if I said that's 10 that's going to be quite a violent explosion.
And they go everywhere but you can still see that's pretty uniform in its explosion.
Now in this particular case we can look down and see there's actually a random option here.
So if we increase this random it's going to increase the random velocity and therefore make it a bit
more scattered.
In this case it's basing it from the emitter the normal explosion of terror value of 10.
We don't want that.
It's probably going to end up a bit smaller in this case.
There we go.
So that looks much much better already now.
But the other thing is these pieces are still kind of stuck upright they're not bouncing off of the
surface as I would expect them to.
Now we can sort of round them hide the velocity for the moment.
There's lots of other things you can play with here.
But essentially we need to turn on rotation and set it to dynamic.
So rotation are affected by collisions and effectors and effectors just other things that affect the
particles some of the turn on dynamic.
And we can see already.
Every time it lands and they bounce they tumble.
Now this isn't dampened enough at the moment sarm going to hop back to the plane go to the physics and
she can turn up the friction I said dampening its sort of movement along the surface hasn't dampened
enough sun and increase that number to increase the random amount as well so you get some stopping before
others.
So to see what's happening there.
Yes.
That's much much better.
So let's go back to the particles and longer select the ball again.
So there's a couple of other things that we can do here.
I'm going to scroll down all the rest.
In fact I'm going to hide them as we go so rotation we can play about with the physics settings themselves.
I'm going to leave those as default for the moment because I don't think it's going to add anything
to this particular set up a rendering.
Now this isn't going to be important at this moment.
We've got material but the material itself is really going to come from the actual ball that we're exploding
and nothing else going to hide the brender tab.
That's absolutely fine.
So the next thing we really need to look at is the field awaits.
Now this is telling blender how there's a load of things here we've not seen before.
I'm only focussing on the gravity for the moment.
The others are from force fields and other effect oars.
Now the gravity itself we can change how our particular particles are affected by gravity.
How cool is that.
So you can actually make a particular explosion last longer by changing its gravitational effect.
Obviously this is going to look less realistic if you wanted everything in the scene itself to be affected
in the same way.
Now if we remember from before the actual rigid body world settings as we saw it here but we also had
a gravity setting.
So we wanted a value that was point one of what it was before.
I'm just going to go down to minus one in this case.
We then get a much similar effect as we had before.
I'm going to set that back to minus nine point eight one.
Otherwise I'll wonder what is going on later Ron.
Okay so we've learned quite a bit now about particles and how we can have them explode our model or
at least separate individual parts out.
And that leads us on to a challenge.
Okay so I would like you to go ahead and shatter a sphere so set up a scene with at least three objects
in it.
And that is going to be a ground plane a cube and an exploding sphere.
The sphere is peaches should bounce off of the floor and stick into the cube.
And here's just a quick example of what I am going for here so you can see the the actual sphere is
exploding.
This.
The shards are digging into the top of that cube and they're just bouncing and dissipating on the floor
itself.
So go ahead pause a video and give that a go.
Okay guys welcome back.
Let's go do this challenge and hop on over in a blender.
Okay so I've opened up a brand new blender fast so we need a cube check.
We need a ground for everything to happen on Oh gone too far.
Let's go plain and I'm going to scale that up by a silly amounts or just minus.
Then what happened there scale 100.
There we go absolutely fine.
So now we've scaled that up we've got this we've got one final thing to add.
And I did say sphere so I'm going to actually go for an eco sphere because that's made out a triangle.
Pretty cool.
Okay.
And it's already got a number of pieces.
I'm only going to subdivide that one.
So let's go in add a subdivision surface modifier.
Excellent we got a good start.
Okay so the next thing we need to do is add let's have a look at the number of faces.
Two hundred forty seven.
So I'm going to add in a particle system with two hundred and forty seven particles are going to set
the start at 10 the end 10 so all explodes at once.
And I'm going to set the velocity I'm going to leave it a one but at a randomness of two.
Okay.
So that's that bit sets.
Not gonna play with anything else there.
And I'm happy with the gravitational settings.
So I'm going to start it playing and we can see what happens here.
They all explode.
Perfect.
So the next thing that I will need to do in this case is start with this plane here and I might add
a collision to it.
Excellent.
They're bouncing.
Let's go to the plane itself I'm going to set both of these at point five and I'm also going to increase
the randomness here as well.
Just so that the particles are all affected slightly differently.
And when you have to have a slightly longer.
There you go.
Otherwise we don't see a thing and they all disappear.
Why did they all disappear.
Because the particles themselves have a short lifetime so let's scroll back up and go to the admissions
settings and Lifetime and was set to at least 100 so they don't disappear on us.
So here we go.
Bounce bounce.
Excellent.
Someone go to the modifiers tab and make it explode.
Hopefully anyway.
There we go.
Still a bit bouncy.
Okay so we can go back to this plane itself and with the collisions we can go to the physics tab and
I'm going to turn up the particle dampening so they don't bounce quite as much and ascent all the way
up to one.
So we should get quite a dampen thing but with the randomness here a few bits there ago will bounce.
And that's absolutely fine.
The friction level is the.
Okay yep.
Things aren't sliding at all.
Excellent so I'm happy with how that's working here.
So I'm going to.
Well what's next.
Do they need to collide with this cube itself.
So let's go to collisions and obviously they're bouncing crazily off of there and I'm literally going
to turn at the stickiness.
I could kill the particles actually.
And then they would stick straight in.
But the problem with that is if this cube were to move or hey that's so cool when that happens and select
the cube.
If we move the cube they stay in place and they're not affected whereas at the moment as you can see
it while they're killing them off at that point that's unkill the particles with them.
Unkilled they actually still interact with this particular cube.
So we can have the cube brush through this debris of we wanted.
So anyway so at this point it may be worthwhile turning up the stickiness and turning up the dampening
and the particle friction all to one then they sticky in as they land rather than doing anything else
perfect.
So the final thing I want to do here is give the cube rigid body physics so it falls.
But of course it needs to interact with this plane as well but have just shifted about.
So let's also give that rigid body physics but of course make it passive.
Okay.
So now everything should fall literally into place.
But something weird is happening so these are bouncing off of the ground.
But not no longer are they sticking to my cube.
Now I have had this a couple of times when I practiced and I reset the physics simulation.
I haven't saved yet that's always a good thing to do when you're playing with physics.
So I literally had a look at this and turned the rigid body off and on again and that fixed the particular
issue I was having.
ST That's all I've done there I've turned rigid body off and on again and it's stuck.
I got really confused because I tried filling about with all settings but if necessary turn the rigid
body settings on and off again.
Now just remember when you do that you can lose your rigid body settings.
Now I haven't set anything up specific at this point but if we had loads settings in here that's not
gonna be necessary.
The fastest way of fixing it I would save my scene itself and reopen it if I was locked into a confusing
situation where things aren't being stuck in.
But there we go we've got our debris scattering around sticking in the top of our cube and this having
real world physics as well.
In fact at this point we could start it off just a little.
Well let's actually start it a little higher and slightly rotated.
So actually hits the ground at a slight angle.
So let's go ahead and play that.
There you go.
It's rolling around.
Perfect.
How did you guys get on.
I'd love to see your results remember to share your work over on the forum and I will see you guys in
the next lecture.