WEBVTT

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Hi it's Michael again! Welcome to

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Creating Collider Meshes! So in this video I will show you

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how to control the number of vertices and we can do that

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in a couple of ways. Firstly, we'll be creating a

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Convex Hull, so the collision mesh works properly,

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and we'll be introducing the Decimate modifier.

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So let's hop straight on over into Blender!

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So here we are in Blender! And the first thing to

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realize is that what we're about to do is destructive.

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So we've got a couple of options how to move forward. We can

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either create a duplicate of our pin and then work on that

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mesh, or we can create a whole new file. So in this

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case, I'm going to create a whole new file just to keep things simple, so we don't

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have multiple models in our scene. And

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also, so when we look at the Info Pane, at the top here, we can

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see the number of vertices and we can just read that out and know that we've met

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our design requirements. So I'm going to go to File,

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Save As, and I'm going to save it as

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BowlingPinCollider! An imaginative name, as you can imagine!

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So, at the top here, I can confirm that's the case, BowlingPinCollider!

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Excellent! So the first thing I'm going to do is make sure this is simple, because when

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Ben imports it or when we export it to any other package,

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we need to make sure that we don't put in a load of other gumf as well,

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So really, some of these things in the Outliner can go.

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So we can get rid of the Camera, we don't really care about that, in this case.

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The Lamp can also go and the Pin Outline can go.

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Secondly, I'm not interested in any materials,

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because this is literally a collision mesh, it's not going to be seen by anything, So, in this case,

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I'm going to delete those two materials, and I'm going to check in this

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here that they've got a 0 against them. Great, so we know

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I've just reassigned it, so I'm going to get rid of that again. That means that,

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on the save and reopen, those materials will go.

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So now we've got our basic pin down. The first thing

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we're going to do is actually make the whole of our shape,

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our model here, convex. And we can do that in

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two ways, and the first way is hopping over into Edit

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Mode, selecting all of the model that we will

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want to adjust, going to Mesh,

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Vertices, and then, up here we have

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Convex Hull. Now the other way of getting

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to that point is, in the 3D window here, if we press the

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spacebar, we... Oh, it looks like that was the last thing I searched for!

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But we can type in here an action we want to perform, and

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in this case, Convex Hull is in there and we can just press Enter. And it

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makes our model convex immediately, so we've got no more

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of the pin neck coming in. And we can take a quick

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look at the number of vertices to see that it has dropped, and it's dropped

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down to 482, so we're not quite at our

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256 limit yet. So the next thing that we can do is start

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simplifying our geometry. Now we could go in manually and start doing that, but there is

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a tool called the Decimate Modifier that will do that for us.

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So if we go over to our wrench over here or spanner,

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we can Add a Modifier, and we have here,

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on the second column, the Generate column, Decimate. Now,

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if you click that and we start playing with the

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Un-Subdivide, it's a nice one to look at because

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it's easy to see and visualize how it breaks up our geometry.

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And if we increase the Iterations, nothing happens!

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Why does nothing happen? Well two fold, number one, we're not in

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Object Mode, so let's hop back over into Object Mode! Oh, and that looks a bit

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funny, so let's bring the Iterations back down to 0 again. So we've got our

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basic pin shape here, once more. Now we do want to change the Shading

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back to Flat and the reason for that is so we can see what's going on.

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So we can see here, with iterations, we can increase that and

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the model gets simpler and simpler. So what I'd like you

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to do now is a little challenge.

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I would like you to create our

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collider mesh. So remember we've got a hard limit of 256

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vertices. Ensure, if you've not done it already, that it is a convex

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model, and finally, the base must be flat. There must be something

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for it so it stands up. So hop into Blender

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now, pause the video, and complete this task!

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OK guys, welcome back! Let's hop

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over into Blender and do those tasks!

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So the first thing is deciding how many

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Un-Subdivides we are going to do. So if we

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increase our Iterations we can see that, at one point,

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it becomes totally unusable. At

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5 iterations that's complete garbage, so let's reduce

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that and see what happens in the rest of them. So here I

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think this looks like this maintains the original width really well. So

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a 0 that's fine, we've got the original width. At

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1 we've got the original width. At 2 we've still got the original width,

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but it starts from 3 and above getting thinner.

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Now that's not going to be any good if we've got a bowling ball hitting a

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pin. In fact, the bowling ball would end up going inside the pin

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and hitting the collider beneath the surface. So looking at this, I think

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2 Iterations would be good! And let's see the number of Vertices that lowers to. That

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lowers well inside our limit to 122.

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And finally, I'm going to click Apply on this modifier,

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so it changes our mesh and so this is now

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the mesh we're working with. Excellent! So the next stage

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is actually making this bottom flat. There's a couple of ways of

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doing that, and I'm going to go in, I'm simply going to View it from the

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Bottom. So View, Bottom, and I'm going to hop into

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Edit Mode, so I can do some work. And let's zoom in! So we

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have the bottom of our pin here, and it's really just this area here that

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we need to be flat and we can double check that. So I'm going to go into

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Edge Mode and select this edge loop inside

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here. So remember, that's Alt and right-click to select

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an edge loop. Then, I'm going to flip back over into Front

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View and make sure that is the right edge to select.

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Well let's go back into Front View and go down. So

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here we have... Oh we can see there that it's certainly not flat, and I

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think I can still do it? I deselected the edge loop there going around.

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Excellent! So the final thing we can do there is,

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if we open up our Properties Panel of the 3D Editor,

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we can set the Z coordinates

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to that entire edge loop to 0. So we're going to go in there,

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making sure it's globally 0. And there we go,

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that's totally flat. So that's going to make sure that's not going to rock or fall

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over for Ben. So let's save this file now! I'm going to send it over

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to Ben and make sure that it works as he expects it to.

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Thank you, Mikey! So I've imported your much more compact mesh

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here and added it to my pin. There you can see the

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Convex lower poly mesh there, and I've given it a bouncy material.

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Let's see what happens! Boing! Ha ha, much better!

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Awesome! Now that's a game dev and an artist working well together! See you soon!