Welcome to light PAFF render settings in this video you will learn about like path's and how they're
critical when using transparency so to give you an example of what I'm talking about in this scene.
We have a lot more grass than we've done before.
And as you can see there are these nasty black and shaded areas.
Well that's all to do with the transparency setting how much light is let through and after it's passed
through a certain number of them it stops and turns black.
Increase the number and you get no more blackness no more horrible artefacts in our image.
So let's go explore this now and hop on over into a blender.
Okay welcome back into blender.
And I've just realized I probably didn't have this one before I do like this particular sky.
But I don't quite like the ground at the moment.
I can always go back and change that the one I was using before wasn't a Mirrorball by an equally rectangular
one.
And if I go ahead and open up the section assets I think it is this one here Sky photo 3.
That's not going to update here until I re render.
So let's go ahead and do that now.
Yes that's what I had on there before.
Because it's more cloudy than the other one of.
Hop back into 3D.
You can see as we move about we've got some sky in there an overcast day yes.
But otherwise looking pretty good.
Okay so let's hop over into the 3-d view and hop in to solve it.
No not solid just go solid lump material mode there and we can see our grass.
So let's go ahead and experience what we mean by light path's and how they interact and to do this example
I'm just going to grab one of these and shift it to the side and then zoom into it on a more socgen
to move the camera off of it for the moment so we can move around quite freely and zoom right into our
model.
Now we've done this.
Let's take a peek at the light path's themselves over in the render tab.
Now if we scroll down here there will be a heading called light puffs and here it is.
Let's make this a bit bigger after making it smaller.
So this area here is all about how light works in cycles.
And important day there's this transparency.
So anything that light passes through after it's passed through eight times its maximum time it won't
pass through anymore.
So let's put that to the test.
So let's go ahead and go into rendered mode in the viewport shading.
We've got our blade of grass here.
It is selected at the moment and I'm going to apply an array modifier.
And it's going the wrong way at the moment so let's do a constant offset on it's going to be the z axis
I believe because it's a texture X some y a left arm.
Why is up so that can be confusing.
Let's just try let's put it on point.
Yes it's gone behind so Z in this case is relative to the object itself the texture itself and because
it's a 2D object.
It has no depth so up is.
And Sideways is Z.
And this in this case going backwards is Z it's very confusing.
But you'll get used to it.
Don't worry there are a couple of other things that are like that in blender as well.
So there's count here what I'm expecting is as we go up to eight.
Now we're starting to see something on the bottom here.
This is called a bit black and 9.
There we go we've got ourselves some horrible blackness.
Now the way to counter that of course is to go into the render tab and increase the number on your transparency's
here and two you don't have it anymore.
In fact notionally you could probably turn up to a hundred for the time being and you would be absolutely
fine.
However it does apply to not only this object here and the transparency going through here but anything
else that you're also passing through.
So if we grabbed another one of these blades of grass and put it in between all of these however many
times we've done it.
We've done it 8 9 4 or we've done it 14 times.
They'll be 28.
That it has to pass through and then it will start going black.
Very confusing.
Essentially you would have to set this higher and higher and higher.
We'll have to watch that if we decide to use a lot of textures for our blades of grass.
So with that in mind get these settings set up get them understand play play around with how many it
takes before it starts going wonky for you.
If you set that down to zero it's no good at all it hardly lets any light through.
It all looks ghastly and of course as this goes up I don't know if this numbers got a top Yes it has
1024.
So in theory with blades of grass would be very easy to hit that number because there are quite a few
blades of grass on the ground.
However we're unlikely to be looking through a thousand twenty four of them and actually see the thousand
and 24th blade of grass.
There's going to be something blocking that any way so that shouldn't become an issue but it's worthwhile
knowing there is a maximum to that.
Okay guys it's challenge time.
And it's a thought exercise on transparency.
So grab a pen and paper.
If one near you or just think about it lots.
Best if you write it down now.
So think about how many blades of grass you've seen might have in it.
I'll give you a hint.
Lots.
Now imagine your laying on the grass looking down.
How long do you think it would take before the transparency level itself didn't matter because another
blade of grass or something solid was blocking it.
Now what would help reduce the number of blades of grass in a straight road.
Other than no grass at all.
And what else could we use to model grass as well.
Think about that.
So pause a video now and write down your answers.
Okay guys.
Welcome back.
Let's have a look at those.
And then I've got another modelling challenge for you afterwards.
So first of all think of how many blades of grass you'll see might have in it.
Hint lots.
It's going to have a couple of thousand at least probably tens of thousands of blades of grass in it.
So it is important that we only put grass where it's needed.
Otherwise we're asking the computer to render things unnecessarily.
Now imagine your laying on the grass it wouldn't take long for more grass to overlap.
So I think after about 100 blades of grass or so you're bound to actually pass through any transparency
problems.
But thinking about the different levels is well I'd probably go for around 150 or so because it is going
to be some grass that's taller than others and especially as you get towards the top of the grass you're
going to have some that are taller than others and obviously then they're going to be able to see further
along what would help reduce the number of blades of grass in a straight run.
Well what you could do is change the level of the ground and that would also change the view of the
grass itself which is a great idea for maintaining a bit more interest in the scene.
After all we are modelling a rabbit in some grass not a field of corn so it doesn't have to be perfect.
And what else could we use to model grass.
Well the clue is in the question we could actually model grass.
Physically it will take us longer to do.
However we've got to weigh up the length of time it would take to model some blades of grass vs. the
length of time it take to render it using the texture's because it is going to take slightly longer
to do that way.
When we come to rendering So there's there's pros and cons to both and will decide later on after we've
done a few tests.
Which way to go.
Okay.
So I said there was going to be another challenge so we're going to hop back over into blender in a
few moments but I would like you to set light parts and create some interesting landscape.
So say your light path transparency tour around 150 This should be ample for this scene.
If it turns out later it's not then you can just just adjust that figure any way.
So it's not a big deal.
It creates some interesting landscaping.
Nothing massive just some subtle ground level changes using the tools you've learned so far.
So pause the video and give that a go.
Okay guys.
Welcome back.
Let's hop over into blender.
Right so the first things first transparency's right here unkissed going to go straight there and set
it to 150 right now that that's done.
We're going to have to create some interesting geometry so let's go ahead.
This is grass I'm going to change it to ground.
Play him.
So I know exactly what it is because it's an it's going to be where the grass is coming from but it
needs to be a bit more interesting.
And I think I actually need our rabbit in the scene as well so I composed the scene properly.
Right.
Oh my grass is pretty small that rabbits pretty large at the moment.
We're going to have to do something to change that.
I think we're going to shrink our rabbit down a little.
So let's just go to the rabbit itself.
I am happy with that.
And I'm going to scale that down by point to a fifth for size.
Who's a little bigger I think points for.
There again I'm happy with the scaling of the Rabbit a bit lower.
Brilliant.
So let's let's think about the ground itself.
In fact why have all this ground in front of our upper Let's move our rabbit locking into the z axis
down here somewhat.
Excellent.
So let's play with our ground itself.
So hop in solid mode here select this and going to edit mode.
Now there's a couple of ways that I can alter the ground itself.
Now the moment the ground consists of four edges four vertices so we can't really do much with it.
Well we could go into the sculpts tooled and do some sculpting with it but I don't think they'll give
us the desired results and the reason for that is it's going to create lots of patchy bits of geometry.
It'd be best if we uniformly divided this and then moved it about.
So you can just subdivide it.
And then in the operator panel down here we can just increase the number of cuts here until it makes
sense.
We don't need it over the top.
I think tens as far as you can go and 10 should be absolutely fine if it's not.
We can always subdivide again now that we've actually done that.
We can go in and pick a face any face at all let's pick that one and go to move it.
But moving it with proportional editing turned on.
So once it's turned on we can pick and choose how we want it to lift up and down.
Smooth is absolutely fine.
I'm going to grab that.
In using the mouse will proportional size is currently very small can see at the bottom there is increasing
and in a few moments there we go.
The cat is actually big enough to have an effect now I don't want to make a mountain like that because
it will look ridiculous so let's just bring it back down a little bit.
It's useful being able to pick those bits up.
Now the tree itself I actually want that's up on sort of like a little bit of a plateau perhaps.
Up there like that so got a bit more interest in the geometry itself and would be here with the rabbits.
In fact it might even rotate the rabbit round will do the sort of composition bits later on.
We can push this ground down if we like.
I'm liking the look of that so far.
I just want this top bit a bit more plateaued a bit flatter so let's bring it in.
It all vary.
Go out how's Howzat looking there I could put I could mumble into the microphone for hours on end schriner
Perfecter.
But I'm happy with that so far it's looking pretty good.
Of course all of my cameras now I've moved the rabbit null and void are happy to sort those out at some
point.
Amber I'm like him the look of that landscape.
So how did you guys get on.
Please share in the discussions your landscapes that you've come up with and I will see you guys in
the next lecture.