Welcome to force fields and particles.
So what are they won't force fields are not SHIELDS that will protect you against anything but they
are a way of exerting different forces onto our models.
And specifically we're going to have a look at particles in this lecture they affect particles more
so than meche objects were play would mesh objects.
In the next lecture.
Now they do not affect themselves or an object if they are part of the physics for that object.
And we see that in closer detail.
Once we hop on over in a blender.
Okay so now that we're over in blender Let's go ahead and first of all make sure that when we're using
the force field itself are no other forces in our scene could be playing with it.
So first of all let's go ahead and pop on a particle system so let's select ucu first particles.
A new particle system.
Now I'm going to set the lifetime to 200 so they do not disappear and moschonas at the end of our scene
two hundred two.
So let's go ahead first of all before we even add a forcefield Let's go and play our animation.
So the first thing we can see here is they are falling and that's because gravity on the scene is turned
on.
So in this case I'm going to turn gravity off some going to go to the scene menu and it's seen properties
here and go down to gravity and just until the gravity box.
Okay.
So now the particles are still moving so there must be some force acting upon them.
Now what could that force be.
Well I'm not going to get you to guess at this point because it's hidden deep in the particle setting
So let's go ahead and switch back to the particle properties and scroll down.
And at some point down here we get to velocity.
So they're having an initial velocity normal to the faces that they're being emitted from of one.
Now I'm going to set that down to zero.
Now as the particles come alive and over frame one two hundred they just get stuck to the face of our
model.
So I'm just going to lower that down to 50 so they all appear in the first quarter of our scene of our
little animation that we're playing.
Okay.
So there are a couple of ways of adding force fields.
One is to the object itself.
Now this cube is the emitter of those particles.
Therefore if we go and add a forcefield to it it does not affect the particles that are being emitted.
If we duplicate this cube over here we can see Virts let's just let the whole animation reset.
Okay.
There they're actually pushing each other's particles away because of the forcefield itself.
Now let's have a closer look at the force field settings so let's scroll down here so we've got a strength
of one.
Let's go back to the top.
Jumping ahead there.
So we've got what type of forcefield is it.
And there are lots to pick from.
Only to leave it as force for the moment.
It's a point force.
And with all the settings left there's the fault.
It will be as if the force itself is being pumped out in every direction.
Equally we've got the strength of the force now the force strength can be negative and positive.
So the moment this cube on the right is pushing away the particles of the cube on the left.
However we can if we type in minus one it'll actually suck them in.
Now the particles themselves will not actually impact of Cube yet because we've not set it to have collision.
If we clicked the collision as well we should see the particles hit the surface and start bouncing off
and deflecting and then being attracted back again.
So this could be great for some sort of I don't know orbital mechanics we are trying to get something
to follow around in fact on this particular cube itself we can see that they're just falling out of
the faces.
But in the particle settings themselves we can scroll down a little the where we set the velocity to
zero where we can say in the x and y direction equally so come out towards us towards the viewer itself.
We can set that I don't know at five and five and let's see what happens when we reset the frame.
They're being thrown out this direction in fact because it's the same particle system that was a bit
strong Let's go down to one and one or not five and one does one and one and reset and see what happens
then.
So they're being thrown out and then they're being sucked in and they'll probably orbit around this
until well until they actually hit it or our animation runs out as we can see there.
So that's now sucking them in towards this.
So that's great.
We can see that they don't affect each other's particles.
However they do affect other particle systems.
Now there are a couple of things that you can do.
Say we didn't want this to happen but we wanted it to curve away anyway.
We can set up our particular emitter and set up the forcefield separately and that's the second way
of adding a force field to our models.
Someone had the leave the other cube for the moment and were going to try and get the same thing going.
But would just this individual one so selected it and I'm going to turn off the forcefield which because
it's not doing anything for us.
He's not changing the direction of these particles.
However if we go ahead and add a force field.
So that's the admen you just like you would add a new mesh object or curve etc..
We've got the option to have a forcefield and it will be added whether 3D cursor is.
And because I haven't moved the 3D cursor it's going to appear smack bang in the middle of our cubes.
Let's go ahead and add a forcefield.
The same one again just a forcefield and that attracts so I'm going to go from minus one on this force
and hopefully our hat so there's not enough ejection force this time round so in that case we're going
to have to make it so would go back to the Q.
Go back to the particle system.
Scroll down to where we have the velocity I think I was actually there anyway so the velocity here is
just being emitted in the it says x direction there that's just check this cube particle just 0 x and
y I was misreading.
So let's set it going off in the x and y direction.
Let's set it up.
Let's try five.
This time it doesn't seem too strong.
Okay so OK they're being chucked out quite a ways.
But they will eventually come back as we can see this slowing down and starting to group and come back.
So five was obviously still too strong.
I'm going to try to leave it at that for the moment.
So we've got this these particles being for south of the system and then being sucked back in which
is pretty cool.
There we go.
They're coming back again.
So that could be you know something being ejected from our model itself and in fact we can do in explode
with those as well and have some sort of funky explosion going on unlike what's going on here so far.
Now in order to make sure that this particular cube itself and the force feel the air that's within
sort of the emission we need to make sure it kind of stays together and in which case we can literally
we can see here it's a field.
It's got the same symbol as an empty and we can drag that in to the cube and make it the parent of the
cube.
Then wherever we move the actual cube itself the simulation I suppose is still running from the same
point.
Brilliant.
You can of course move them individually if you select individually.
So I'm just going to.
Undo those couple of moves.
Okay so we're back at this point here what happens now if we have more than one of these because they
are self affecting and they would affect others.
So let's go ahead and duplicate that cube and pop one here one here and one here.
We should start getting some interesting effects.
Because these are all emitting However only one of them is attracting.
So you can start to get some really interesting orbits going on or suctions or whatever you actually
wanted to do.
Of course we all know that these particles themselves can be changed to be objects as well so that could
be a swarm of bees or whatever he wanted it to be swarming around that central cube.
Okay.
So armed with that knowledge I've got a quick challenge for you.
Okay I would like you to go ahead and dissolve a cube.
So set up a cube that will break in two blocks of pieces.
I do recommend setting it up in a zero gravity environment initially just to get the hang of what's
going on.
If you have any gravity whatsoever things will just be poured southwards in negative z direction by
default.
Course if you go ahead and change the gravity to a different direction it will disappear in a different
direction.
So use a force field to break the cube up into little pieces as if it was be made out of fragile sand
and it was just eroding away.
Borzov video now and give that a go.
Okay guys welcome back.
Let's go dissolve a cube over in blender.
Okay so this is where I left off here.
This is where we've got some particles being emitted.
Now we can use those particles obviously to dissolve cubes.
Now we need the cube itself to be in multiple pieces and to make sure that I'm not repeating myself
a you're going to use the scene I've got set up here because I think that would be quite interesting
watching it being blown apart and then swirling around this central bets.
I'm going to literally make sure all of these cubes have the same meshed data.
So all of these are obviously different objects.
Do they have all different mesh objects or mesh data.
Yes they have.
So I'm literally going to switch them all to just cube.
So a bit of a time consuming thing but it's not going to take too long.
There's not too many of them.
Of course I could have just selected them all and made a link to them.
So there's lots of ways of doing things in blender are chosen to do a little long handedly.
Never mind.
Okay so all of these are sharing the same mesh data which should mean if I go into that mesh data and
subdivide I'm gone.
Press Dubey there is term a keystrokes I'm going to press Dubie there and that subdivide and going to
open a tall shelf and how many cuts are we going to do.
Well bear in mind this is going to be multiplied by five times as well.
I'm going to go for maybe 250 cuts.
Well is that going to be too many might know though.
That's tiny.
Oh how.
How many faces is this produced 61000.
Yes that's going to be a bit too many that's going to slow down my computer something chronic.
So let's try 15.
Yeah that's a much better.
Fifteen thousand faces.
OK.
So now I've done that.
Every other one should also be 15000 faces.
Sure.
So we have got how many phases in total.
Eighty thousand.
OK.
And these are all sharing the same set up.
So we should have no trouble at all making all the settings to say some let's you can add the explode
modifier to our first mesh here.
Excellent.
And a way it goes it's orbiting properly.
Excellent.
And it's it should be a matter now of adding the explode modifier to these other bits.
So modifier explode modifier explode.
Again I could make links across or it's starting to slow down now so perhaps I had a few too many.
Anyway that's that's a good start isn't it.
So there we go.
Okay.
Some may be too many there but we can see the cubes rule breaking apart and they're all in separate
locations and they all start to orbit round.
Now what I'm going to do is I'm actually going to let this run this animation itself for a little bit
longer.
Some gear up this and I will see you guys back in a few moments once I've left it cashed all this out
and I'm going to render it out as well just to see what it looks like.
Of course cinnamon make sure my details are low so I'm just going to pause it there and before I go
off and disappear I would consider going to show you how I'm going to set this up.
I'm going to go to the world properties and set a colour background to basically black so there's no
ambient light in our scene and I'm just going to switch here over surrendered modes it's going to look
like that.
Now we've got this sort of bready colour I'm going to go in and pick something a little lighter.
And of course I've got some materials here you can choose a different colour if you want it.
I'm going to go from my terracotta colour mainly because I like fat.
And then finally the light in the scene is all coming from a lamp.
And at this point all of these pieces of course will self shadow one another.
But if I go ahead here and we've got sunlamp with a setting of three let's set it a little higher.
Okay that's five let's go for 10.
Okay.
That's getting some real highlights on it.
Now let's zoom in and make sure it's real blowing out.
Okay I like that as well.
OK.
A final thing I'm going to do which will tax my computer so I may end up leaving it a while to do the
run in fact I'm probably going to do it on my P C which is a bit quicker than my laptop.
I'm going to increase the number of particles for each one to the number of faces that are on each cube
and if we remember there were something like 15000.
That will give me a lot lot smaller set of particles and I'm going to run that simulation and hopefully
get some sort of ring system going around my central point there.
So I'll see you guys back in a few moments whilst I've sorted that out.
Okay so things have changed not too dramatically.
I've still got a load of cubes that are dissolving but I've replaced that middle one with a sphere and
I've kind of got a young Saturn.
How about that or something else.
Like I have no planet with Square moons that have been broken up anyway.
So this was super exciting to bake and when I was making it I was shocked to see the resources it took
up so a word of warning.
This particular blend file with all of the cache data for those particles and their movements because
blend the stores that ballooned at 12 gigabytes.
Not to mention that blender used well over twenty eight gigabytes worth of RAM when actually rendering
this out now suffice to say if I was trying to run that on my GP you there was too much data for that
to handle it just crashed out.
So this is the sort of thing that if you start getting lots and lots of particles you are going to suffer
ram issues vs ram issues even on modest cards like a titan X or something crazy like that.
It's got 12 gigabytes of RAM cost thousands.
So in this case a s.p. you would be the best place to render this on as you can see.
This was lots of fun to make.
I hope you guys have made some similarly wacky dissolving of the cubes.
Oh so you've gone remember to share that work over on the forums so we can all see it and I will see
you guys in the next lecture.