Welcome to copying physics properties.
So where is the physics data actually stored.
Well see in a few moments.
Physics properties are not linked to the objects or data.
Data block.
As you might think they are like the materials are when you set those up.
Now they are part of the scene data block and this means that unfortunately when you append an object
that you've set physics up.
Well the actual data itself is not going to come across for the physics set up you'd actually have to
import or sorry in append the scene itself into a new blender far because that's where all the properties
are stored.
Now you cannot make links to the physics either.
So when you used to use and control an L to steal the material data from another area there's no option
for physics.
Perhaps that will change in the future that will be very useful but it's not possible at the moment
simply because we're stored in the scene data block.
Again it's not stored as part of it objects or the object data day to block.
You can however still copy from an active mesh object and will it go explore that now and hop on over
into a blender.
Okay so were over in blender here we have aged the standard cubes we would do normally that sets some
physics up on it's us.
Go ahead and just add it.
A rigid body like we've done before and let's go ahead and play that.
So one of the ways that you can get data from one object to another is of course copying or duplicating
the object itself.
So let's go ahead and stop that from playing that's go back to frayne's ZERO again and using shift and
D we can duplicate our cube and both of them now have physics properties apply to them because it's
derived from the original.
Now if we change it with let's say we go in use all the and make a linked duplicate and just to remind
you that means that they are linked.
If we scale them in edit mode they will scale on both of them scale because they are actually the same
mesh data.
Now.
They will all have the same ply But of course if we set this one having a mass of 5 If we go to this
one it will have a mass of one and this one will have a mass of 1 as well.
And of course that in itself you would think would be a little bit problematic.
It is if you don't know how to handle it.
So first of all before we go any further Where is all of this data stored.
Well it's actually in the scene itself.
And if we scroll down so in the Properties window there is the scene tab it looks like a ball in the
cylinder and a.
I suppose it's a lamp next to it as well.
I can't quite make all of that out but we've got a series of options.
We've got gravity in here now that does affect our scene so if we changed to where the gravity was coming
from at the moment it's set to nine point eight one which is meters per second in this case.
And if we end up just playing it by default.
There we go.
The others just disappeared.
So that basically means that after one second these queues will be travelling as they've accelerated
at nine point eight 1 meters per second.
They'll be travelling at nine point eight one meets per second so after a second if you want to know
the full equation you can go hop over onto Wikipedia but they will have travelled around 5 meters or
so after a second or in this case blender units B because one blend the unit and one meter are pretty
interchangeable when it comes to the default scene that we have.
Now these are falling away.
That's absolutely fine.
If I Antec rigid body world well the physics just stops working because that's where this data is stored.
Now we've got some other options down here the useful ones down here.
And these are some of the trip ups that you'll come across the gotcha's.
We can change the steps per second we can change the solver iteration the higher these numbers the slower
your calculations are going to be but the more accurate they should become.
Don't go too high though other ways you can also give some very undesirable results where things just
go flying off into the aether to stop these things falling.
Okay.
The one that usually gets people is this rigid body cache.
Now if we open that up we can see it starts at 1:00 and goes to 250.
And it says we got 50 frames in memory and it's taking up 12 killer bytes.
That's fine.
That makes sense if we change any of the settings to do with the physics that's go over here and make
the maths two and go back here.
We should see that it says outdated.
No it doesn't.
Let's just change something else the friction and go back here.
Perhaps it needs to be running to be outdated.
There we go.
Cash is out.
And if I pull this open he says outdated.
There we go.
So the cash is outdated now.
The important thing here is the start frame and the end frame.
Now if you were doing quite a long simulation at the moment it would literally stop after 250 frames.
It doesn't matter if you've changed the setting down on the time line to be 300 400 500 It doesn't matter
2000.
It will still stop the simulation after 250 frames and that is something that will catch you out.
If you all do less doing a Domino's scene for instance where one block is hitting another and there
cascading down well after 250 frames or 10 just over 10 seconds at 24 frames per second.
Its just going to stop and if you wonder why go and check out this setting here the rigid body cache
is literally storing the information.
Now what we don't see with these simple cubes falling Let's go back over here is it's kind of locked
24 frames per second.
If it was a more complicated simulation we would see it drop down perhaps even less to one frame per
second.
But once it's run that it's actually stored those 50 frames in this case into cash.
So it doesn't have to recalculate the movements every time.
However everything that you change will actually make the whole cache out of date.
And that's that's the case sometimes you'll do something whilst the animation is running and things
just explode or fly over the place and you just wonder what's going on.
Well if that does happen just reset the simulation or let it loop round any way especially if it's a
short simulation like 50 frames.
So now we've got all of these cubes all set up what we can do is copy the physics from one to another.
Now this is available in the tool shelf under the physics pane and every year.
That's the fifth one down here.
Now we've got a button that says copy from active.
So the easiest way of doing this is well there are a couple of ways of doing it.
But the easiest I've often found is to move all of your objects that you're working with to a separate
layer.
That's one way or in the outline a D select the selection for things you don't want or that you're not
working with at the moment so we've got these three cubes.
Now if I select everything with the aiki is only those three being selected and I can also move them
to another layer like layer 2 and then when I'm looking at that I can simply just hit a and select everything
that's on that layer.
Now I select the one hour and want to copy the information from first it will go that light orange colour
on the origin.
Now because they got physics applied.
Unfortunately we can't look at the actual outline because that's just gone green.
Now let's have a look and see the settings.
Let's give it a friction of one a bounciness of point five and a mass of 10 which we definitely can't
see and let's change it from convects hole to mesh just for this instance.
Now now we've got all that set up we can hit the A key twice and you see that the other origins for
these particular cubes are a dark orange in now if we hit copy from active it's copied the physics data
from this cube to the other two and if we can go and click on them we can see that that is in fact the
case.
They're now all contain the same physical properties.
Now this can be a great way of let's say setting up a scene with multiple lights and you just all set
them up with the same physical properties and then go in to tweak them.
Or indeed if you've got lots of duplicate objects that are actually the same that do need the same physical
properties you can apply across the board.
So now just to practice this I've got a small challenge for you.
I'd like you to go ahead and copy some properties.
So go ahead and set up a scene with five falling primitives and a slightly sloped ground plane so it's
a bit more interesting when they hit it make all of these mesh objects saying that they share the same
physical data.
So they're all going away the same have the same bounciness et cetera.
Now remember to make the ground plain passive.
Otherwise it's going to disappear with all the others and nothing will hit one another which wouldn't
be that exciting.
So go ahead.
Pause video now and give that a go.
Okay guys welcome back.
Let's get set up a scene and hop on over into a blender.
Okay welcome back sir.
We have three cubes here.
I'm going to get rid of two of them.
That's fine.
Okay.
I'm going to add in a plane and just scale that up massively So we've got something there and I'm going
to save my file as well and call it 5 falling objects.
I cannot see my microphone so hopefully that's I can't see through my microphone five falling objects
just got capital in the wrong place.
Anyway enough of my keyboard wizardry.
Let's just play Well let's set all let's add are other objects him first so what else can we have.
Let's have a cone.
And for excitement's Let's actually have the cone rotated X by one eighty six pointing down.
Who knows which way it will actually fall.
Let's hear.
Add in a nother meche let's add in Suzanne the monkey she's always useful to have in a scene keeping
an eye on us and our antics.
There we go there's Suzanne a schifter over here so she's not getting a cone falling right on top of
her.
And then of course that's three so let's go in.
Now I've got three extra things added in so let's see.
That's all teapots are that's going to come in pretty large that's shrink it down just a little and
move over here.
And what else have we got.
We got one more object.
What shall we have.
Choices choices choices.
Let's go for a cylinder and let's tilt it on its side.
So I'm going to rotate it round the y axis by 90.
There we go.
So that's a great starting point.
And now I'm going to.
This one's already got physics properties enabled so I'm going to select everything from that go over
to the physics tab and copy from active and then remembering to set this to passive.
In fact I can just hear and passive over here.
That should work it's not rotated yet so that's were it's hates it ever so slightly.
And let's see what happens when we go ahead and play.
Now we've only got 50 frames so I'm going to up this now to 200 just to see what happens.
It turns out yes.
There we go.
The cone does indeed fall over.
Now of course we could make things a bit more interesting we could make the floor a little bit more
bouncy.
And let's go to this cuber make that very bouncy in the friction a little low.
There we go.
So the cubes bouncing about was probably a bit too much bouncing this bouncing.
This a new word.
Never mind let's select these other objects and then copy from active which will be this first one again
copy from active.
Let's see what happens.
Now they're a bit Pouncy Yeah.
Excellent.
Lots of fun.
How did you guys get on.
I hope you're getting the hang now of the physics engine as you can see it's got quite a bit of potential
and quite a bit of confusing settings over here.
But rest assured we'll get to the bottom of most of it and we'll have lots of fun whilst doing it.
Please share your five falling objects in the discussions on the forum and I will see you guys in the
next lecture.