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‫So this is just going to be a quick lecture on trying to understand why we're getting this weird glitch

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‫here when we move from the right of this first spawn point.

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‫Now, let's dive straight into this one without an introduction.

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‫The idea here is that something must be going wrong with the collisions, collisions being those simplified

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‫meshes around the world that allow us to do physical, physical calculations.

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‫Basically, what can we stand on?

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‫What can we not?

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‫Because they're often simplifications of the meshes that we can actually see for performance reasons.

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‫So how do we see what the collision world looks like?

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‫Well, fortunately, in our viewport we can go to the lit mode, the button that by default says lit

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‫at the top left.

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‫And you can see as different view modes here.

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‫Some of them are things like unlit removes the lighting.

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‫You can see the wireframes of the meshes, but the one we're interested in is either the player collision

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‫or the visibility collision.

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‫Now the difference being that the visibility collision is the more fine grained meshes and the player

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‫collision is that coarser grain mesh and you can kind of see the difference there.

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‫I think that's quite obvious.

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‫When you click between the two, you can see the coarse grain and fine grain nature of things.

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‫But if we move over here from this particular angle, you can see that there is a mesh just poking through

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‫here, a collision mesh that we do not want.

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‫Where is that coming from?

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‫Looks like an error in our asset pack.

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‫If we click on it, you can see it says floor filler 27.

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‫Not very helpful.

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‫That's the name of the actor.

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‫But if we go and have a look at its static mesh component and the details pane and have a look at its

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‫actual static mesh, we've got the SM stairs, a one.

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‫Now if we browse to this asset using the little magnifying glass and open it up, then we're going to

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‫get the static mesh editor opened up in Unreal.

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‫And what we're interested in is having a look at collisions.

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‫So to see collisions, you go to this collisions button and you can click on both the simple and complex

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‫collision that shows you there's two different measures here.

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‫The complex collision is for when we're doing finer grain physics and is often the same as the visible

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‫mesh.

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‫And then there's the simple collision, which is just a kind of course of grain version, as we've been

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‫saying.

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‫And you can kind of see that difference there as a nice coarse grain mesh.

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‫And what happens if we have a look, if we've got this coarse grain, simple collision selected and

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‫go below the floor is you can see there's this massive strand going off down there into the distance.

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‫That must be what was causing us our collision issues.

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‫A little bit of an error in the asset pack.

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‫Few ways that we could deal with this one might be if you go to the collision menu, you can remove

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‫collision, which is entirely removing collisions.

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‫You can then regenerate it using a bunch of different options that are built into unreal, such as you

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‫can add a sphere for simplified collision, a capsule box ten DOP 26 DPI.

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‫Lots of different options here.

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‫Auto convex collision.

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‫We're not going to do any of that because actually we can fix this up pretty straightforwardly.

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‫Oh yeah.

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‫One more option would be that we could set the complex collision as the simple collision.

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‫There's an option for that in the details pane, but we're not going to go down any of those routes

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‫because actually you can do a little bit, of course, grain mesh editing right here.

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‫At least we can delete some vertices.

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‫So if we go ahead and select it while the collision mesh simple collision meshes visible, you can select

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‫this set of edges or the face that goes all the way down here.

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‫And you can see that's all that's selected.

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‫That's the only thing that's changed to a lighter green color.

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‫That's how you can tell.

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‫And if we add delete, then you can see that goes away and it doesn't actually affect the rest of the

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‫mesh.

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‫The rest of the mesh is pretty solid, still looks pretty much as we would want it to look.

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‫And if we go even in this viewport, we can go over to the player collision view and you can see what

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‫that mesh looks like.

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‫It's a little bit funny in places, but it will work.

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‫So if we go back to Lit.

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‫And then go over into the sandbox.

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‫You can see now that little shard has disappeared from our player.

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‫Collisions can go back into lit and hit play.

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‫And now if I go over to the right and move around here, there are no collision errors whatsoever.

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‫And because we modified that stair mesh, let's go down the hallway and try going up and down the stairs.

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‫Yep.

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‫The collisions there still seem to be functional.

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‫I'm not dropping through the floor or anything.

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‫I'm able to go up them and it's not a kind of discontinuous jerky motion.

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‫So Astaire mesh is now fixed and you've learned as a result of it a little bit about how collisions

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‫are set up against static meshes in Unreal.

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‫The next lecture we're going to be going back to animations and understanding the animation blueprint

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‫to create much more complicated animation behaviors.

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‫I will see you there.