New (?) Waterfall Mechanic Tech Demo

[rtm223]

I've just published a tech demo for a waterfall mechanic I've developed, which I believe to be new, although it wouldn't surprise me if someone has done anything similar. I've never seen it anywhere before and personally I think it looks bloody lovely I've actually published it as it links in with the fabled next installment of my logic blog, but I figured this would have wider appeal than those who want to read about logic, what with it being pretty and that.

Logic blog will be published tomorrow (no really, it just needs a proof read), with details of the method, and I'll probably add more specifics of getting it to work as a waterfall shortly after.

Anyhoos, lemme know what you think.


Edit - sorry no pics, but they all looked naff, so just go look when you're on LBP

Edit again - Oooops, forgot to give credits, these people provided some very important additions so thanks to them:

Comphermc - sitckering.
Javi haguse - foliage.
Syroc - a box of sponge.

Awesomely Awesome Step-by-Step Guide

So, as I described in the blog, the waterfall is simply an extension of the conveyor belt, in fact, mechanically it's no different from the conveyor belt - it is just a block of material moving at fixed velocity on a piston. So the best starting point is a simple block of material:

This thick layer rectangle will form the main part of the waterfall. It is grid aligned and 50 units (5 big grid squares) high. The width is irrelevant, just make it as wide as you want it to be - but keep it grid aligned. If you refer back to the pictures of the conveyor, you can see the join between the blocks, which is something that we want to avoid (as much as possible) with the waterfall - we want it to look more natural than that.

The first step towards this is to break up that straight line at the bottom, but remember: we still need these blocks to emit and perfectly align, so that means we're still using the grid. Just add in some diagonals (using the corner editor) that match up both top and bottom.

The other important factor here is that we need an anchor point for the piston. Once again, precision is required and the piston needs to be travelling straight downwards, and the best way to achieve this is grid alignment once again, so we will make a 5-units (2 small grid squares) wide horizonal line at the top and of course, at the bottom as well.

At this point it's best to check that you've actually done this right. you should be able to copy and paste the object directly below itself (still in grid mode) and get no merging of materials. As an alternative to this process you can just do the top edge and the copy and cut it out of the bottom. It's your choice.

Important note: One problem I did hit with morganna's waterfall was that if you have diagonals that are too steep, you may be able to do the copy/paste test successfully, but the emitters will fail on it. I'm not sure why, but the phrase "rounding erros" is springing to mind.

We still aren't looking very natural here though, so turn off the grid and shape up the sides. I've gone for something relatively subtle here - just a kind of loose wavey pattern - remember it's going to be travelling past pretty quick so vast numbers of vertices really aren't necessary. Tip: make sure the top and bottom of each side match up still - you don't want a harsh angle in there.

So that's the shape of our waterfall made, next to add the mechanics. Connect a stiff piston to the anchor point at the top of the waterfall and then we need to tweak it to the correct speed.

This is the tricky bit, so pay attention.... So take the equation from my blog and remember we need P to to be some multiple of 0.1. We know the value of the object length (d) and if we set the minimum length of the piston to 0, we have a much simpler equation to deal with:

         d t
p = -------------
      2 (L - l)


     60t     30t
  = ----- = -----   
     2L       L

We want L to be something pretty long as we need enough space to spawn the waterfall out of sight above the screen and have it drop out of sight at the bottom before we can allow it to vanish. As I mentioned in the comments of the blog I prefer to have this length longer than needed, so that the piston will never fully extend before the emitter lifetime expires. So lets plug in a max length of 450 - which is way taller than we need and also another nice round number (no need to make life difficult for ourselves eh?) If we plug these into the equation and rearrange:

     30t
p = -----   
     450

t = 15p

Remembering that p is the emitter timing, we know it has to be a multiple of 0.1s. For a sheet of material 60 units high, having 2 go past every second seems like around the right sort of speed we want, which will require a value of p=0.5s, giving a piston timing of 7.5s. In summary:

Piston Minimum Length = 0
Piston Maximum Length = 450
Piston Time = 7.5s
Piston Visible = No
Piston Stiff = Yes
Emitter Lifetime = 0.5s


So tweak your piston to those values, attach a grab switch to the dark matter and tweak that to be directional and inverted and connect it to the piston. Unpause and your piece of glass should shoot down in a straight line and stay there. Assuming it works, rewind and capture it. Put down an emitter and tweak the frequency to 0.5s and make your newly captured waterfall the emitted object. Make yourself a viewing platform and observe:

Rewind.

You will probably have been able to see the join quite clearly if you are looking for it, as shown in the picture above. To help disguise this, we will use the fact that if you have two layers of glass on top of each other, the back layer becomes invisible. Obviously this means that if there are two pieces of glass behind, the join between them becomes invisible:

Note that I've swapped to the PotC glass here, partly because it shows up the join better, but it actually looks a lot prettier too once it's stickered up in the final product.

So attach some thin layer detail to the front of the think layer piece in such a way that they overlap the join on the waterfall. Note I'm just using 4-6 vertices per piece, it's going to be rushing past so no need to overdo the detail. I'm sure some of you will come up with far more impressive patterns than me, but I to much detail will probably be wasted effort IMO:

Make sure again that you can still butt two of these pieces together in grid mode, and that you haven't messed up the overlapping and there aren't any empty areas.

Put this object in the emitter and unpause again and your new, improved waterfall should just work as all the timings etc are still valid:




Now it's just a case of stickering and placing in situ. Then of course adding some lights, gas, rockets, sound objects and of course, your trusty box of sponges

[comphermc]

Haha. What's a box of sponge? Lol. I needed a paperwritingbreak, so I'll check it out. I still think the little vine is the coolest!

[Littlebigdude805]

pretty, follow the waterfall down the right way with your eyes and you can see the breaks still a very nice method.

[comphermc]

Ouch... two stars when I got there, lol. By sponge box, do you mean invisible barriers? Because I saw no sponge.

[dajdaj03]

Just had the time to see this before my PS3 froze...


It looks really great! The fall is very smooth, and there's no visible transition which is great!
I'm not a Logic expert but I'm curious to know how you did this...

I think I never saw this mechanic. The water falls that I know are not that smooth, but more shaky (fast emitting).

Can you for example set its speed?
I was thinking that maybe if is was a little faster, maybe it would look even more natural...?
Hum...don't know, I'm just imagining


Anyway great work!

[rtm223]

pretty, follow the waterfall down the right way with your eyes and you can see the breaks still a very nice method.

I know you can - it really does show up in the stills sadly. Personally I think it's easier to see the repeating pattern than the breaks, but yeah you can see it. I've been thinking about spliting it up into thick layer, thin layer, and checkpoint thick layer and have them moving past each other at different speeds to help disguise it. But that feels like a lot of work

Ouch... two stars when I got there, lol. By sponge box, do you mean invisible barriers? Because I saw no sponge.

2 Stars? Haha, how many "rubbish" tags did I have? You won't see syroc's box of sponge, but you can hear it layered in with the other sounds if you listen really really hard. It adds a little "bubbling brook" sound into the mix

Just had the time to see this before my PS3 froze...

I swear this has nothing to do with me.

It looks really great! The fall is very smooth, and there's no visible transition which is great!
I'm not a Logic expert but I'm curious to know how you did this...
Can you for example set its speed?
I was thinking that maybe if is was a little faster, maybe it would look even more natural...?
Hum...don't know, I'm just imagining !

You can play around with the speed, but it's quite hard to make slight adjustments to it. For example, I think it would be easy to make this one 20% faster, but 15% faster would be quite hard. Essentially some speeds are easy to achieve, others are harder and some are impossible without a complete rebuild. Sorry I'm being a little bit cryptic here, but I've already written up the technical details of it and they will follow in a couple of hours.

[Syroc]

Syroc - a box of sponge.

Fame at last!

(The gold coin material makes decent err coin sound, by the way)

I actually like that type of waterfall more than the standard glass pane moving quickly up and down or a million pieces of glass being emitted over and over again. I feel it fits the game overall better.

[Ungreth•]

Got treated to a live demo of this the other day, and I can say without any doubt that this is the prettiest waterfall effect I have seen in LBP yet.

Oh the irony, that our resident tech-geek should have outsmarted the aesthetes in the visuals department! Next we'll be hearing that Teebonsey has produced a lower thermo toggle switch than rtm or comph, and the world as we know it will be turned on it's head and given a huge wedgie.

[lbpholic]

This does indeed sound pretty kewl i might try and use it somehow in a level me, plasmavore, fredrik94 and ghostrider are workign on, i can't wait to check this out.

[julesyjules]

Just checked it out, looks great guys. The detailing in the nearer thin layer (im assuming from what i saw) really makes it. I would have hearted it but I couldn't see the sponge box, sorry!

[rtm223]

OK, blog is up with an explanation on how to achieve this http://www.lbpcentral.com/forums/ent...locking-Theory. If you aren't that interested in my overblown technical investigations then feel free to skip to section 2.0 which is the tutorial on conveyor belt mechanics which leads on to the waterfall.

I'll update the OP later with some tips on getting it to work as a waterfall so it's convincing, but the best starting point is to build a conveyor belt using the described method.

[Syroc]

I would have hearted it but I couldn't see the sponge box, sorry!

Pff, it's not something you see its something you experience...

I shall make a thread about it so as not to derail this thread. There will be drawings! Edit: Here ya go

[julesyjules]

It was a joke. I went in expecting a to see a lovely sponge box.

[Littlebigdude805]

that would be awesome if it was put in a place where the player would be able to see it for a while like in the background of a boss or maybe a hard puzzle, the water shifting past itself may seem more natural and add more wow factor but not worth it if its just going to be seen for a second or two.

[Kern•]

Its good, but it needs MOAR WAT0R!



Well its pretty sweet, If you can perfect it.. Not that its not perfect already... erm.. erm Sticks head in sponge box