View Full Version : Dynamic Water in a glass ?

02-04-2005, 10:45 AM
Hi to you all.

I was working through the "faucet" tutorial in Dan Ablan's InsideLightWave8 (chapter 17), and decided to try to make my own scene from scratch and do some dynamic tests.

I've finished the models and shader, so I guess it's time for my to animate. I have two models. One Transparent Glass, and a Alminium Vase. I was planing on puting the hv_emitter in the neck of the vase and set it up so the textures will pour out of the neck and into the glass, filling the glass with water.

Now here comes the big question!?! Can I just use the particles to simulate the water filling the glass with only using a HV_emitter and LW8.0 dynamics?

In Dan Ablan's tutorial, he animates water spraying out of a faucet and then it just glides down the drain, so the tutorial really can't help me filling an object of particles. I always get them in a big pile on the bottom.

02-04-2005, 11:12 AM
no it wont work.

The filling up part will have to be a poly model.

Realflow will do this kind of thing, but lightwave's particles are nowhere near capable.
Realflow generates, from the particle simulation, a sequence of meshes that is used frame by frame to animate the fluid effect.

02-04-2005, 11:22 AM
and it's as good as "it won't." The particles won't move at all like you want and the HV's won't render like you want. The HV's will be lumpy and they'll ignore the sides of the glass.

Realflow is indeed the answer.

02-04-2005, 11:31 AM
Thanx u guys for the info... It was a good idea to ask about this here before I went on and tortured my self :)

Could I get a reasonable effect by using a poly model with endomorphs or something similare?

And where can I find more information about Realflow?

02-04-2005, 02:06 PM
RealFlow is relatively expensive..starting at $1200 (but very good)


You can do it with polys but it'll be lots of work to get it really convincing.
It partly depends on the shape of the recepticle too.. a straight sided one is easier to make a filling up morph for than a goldfish bowl as the latter has to move in and out too at the edges.

What I would do is make a filling up morph.. (maybe you'll need more) and extra morphs to animate the surface

make a weightmap for just the top surface.

Displace the top surface (using the weightmap) with ripples etc and a 'dip' where the pouring meets the surface.

Add an emmitter which shoots particles down from the point where the pouring enters to simulate bubbles with hv's

Make the pouring water object separate, displace it and blend it to transparent where it meets the mass of bubbles.

02-04-2005, 02:14 PM
Well I've used Realflow since it came out and the latest version is awesome.

It will do exactly what you are looking for.

The only issue here is having the ca$h to get it.

If you do you'll be well on your way.

02-06-2005, 08:06 PM
Thank you a lot people!!! I'm very sorry to say that I'm going to postpone my project. I took a look at RealFlow..... and got pretty **** exited :D I think I will have to try out that demo soon... (BTW does anyone know if you can actually use this demo, or if you can just try it out?).

I was going to try out doing this waterfilling scene with only what LW has to offer, I wanted to know if I could do it :rolleyes:

Turns out I probably can't, couse my render times are already unreasonable.... became that way as soon as I put that water model in the glass (I'm guessing it's the extra refraction that makes this such a heavy render). Anyways.... I'm going to post you the renders I had already done before.

Here u' go :)

02-07-2005, 12:54 AM
If that's an area light in your scene (not a spinning light), that'll be the reason why your render times are so large: area lights + refraction = potentially big render times. You have a simple scene there, and even with refraction on render times shouldn't really be too much of an issue. As a side note, you really ought to add an air object (a flipped version of your glass object, IOR set to 1) to your glass as it isn't refracting properly, i.e. it looks full even when it's empty.

02-07-2005, 10:11 AM
your blurred reflections are also making your rendertimes longer

08-27-2005, 07:07 AM
(BTW does anyone know if you can actually use this demo, or if you can just try it out?).
I was going to try out doing this waterfilling scene with only what LW has to offer, I wanted to know if I could do it
Yes, the Realflow demo is fully functioning, however, during the simulation you will have to dismiss a splashscreen which pops up regularly.
Make sure you have the latest Realflow>LW>Realflow plugins installed [free from Nextlimit.com] and be sure to check out their LW-specific plugin video tutorials on the site.
Realflow is an awesome program - but be ready to tweak and tweak the parameters to obtain convincing sims. It's hardbody and elastics engine is superb, also, and is capable of producing incredible results that would be all but impossible using LW alone.

08-27-2005, 07:25 AM
So if RealFlow generates a mesh for every frame, I guess it wouldn't work well with motion blur, eh?

08-27-2005, 08:00 AM
Realflow is excellent with motion blur. It saves the info required with each frame and you just set up the motion blur the way you normally would.

Last year I animated a glass of water that had to agitate like a washing machine. Using Realflow and lw together made it fall into place beautifully. And it was largely the motion blur that was responsible for the final look being totally convincing.

A client of mine from other work was surprised to find out it was animated. He'd been racking his brains trying to work out how it'd been shot.

08-27-2005, 09:28 AM
Hello to all,

There are two FILL GLASS SCENES in

\Content\Classic Content\Scenes\_Features\ParticleFX2

called FXCollisionCup.lws and FXCollisionCupSwish.lws

They have the dynamics motion recorded, but show how they fill a glass.

I've tried several times to clear the motion recorded with different LW version since 7.5. And sometimes you get correctly the movement back or a complete mess (LW 8.0.1). I pointed out this a long ago on another thread but I've never saw a REAL explanation on how this scene work, even when I split it into pieces to understand it! :)

Maybe you want to look to this and figure out how the heaven they work ! :)

In other case I recommend you go to RF at least, for doing a test its fine.

Hope it is helps.

08-27-2005, 09:44 AM
you mean like this?

from the lightwave 3d book that came out in 1997!
using lightwave 3.5
no particles....
no hypervoxels....

just some creative thinking! :)


08-27-2005, 09:50 AM
a selection of frame renders



08-27-2005, 09:56 AM
i'd post the scene/models for you but they're from the lightwave book's cdrom so i'd need clearence from the author...

def. worth thnking about getting this old book for yourselves from amazon as there are a wealth of neato information for lightwave and as you can see they were not put off the task by the lack of a particle system, hypervoxels or the latest wizz bang expensive plugin like realflow/real wave........ :thumbsup:

isbn 0-87930-455-3

the lightwave 3d book
published by miller freeman books

:newtek: :hey:

08-28-2005, 03:29 AM
How about explaining how it was done in that scene?

Also if you are a student you can buy an educational license of Realflow for $95. Good for learning it, you just can't use it to make money.

08-28-2005, 05:42 AM
the 2 sets of water were morphs with object disolves to bring them in and take them out of the render and the pouring water was a object with texture displacement to create the distorted look of pouring water and was controlled by bones which are animated to follow the way water is poured out...he used some placed nulls for reference so they animated along a similar path to that of the first bone...he used 10 bones wich all started off inside the mesh then moved out to pull the mesh out of the top jug down tward to other jug....

simple eh? :thumbsup:

08-30-2005, 01:24 AM
Aloha cresshead,

I found the scene you talked about on The Best of LightWave Pro.
Unfortunately I tried rendering it and at frame 173 the render just freezes.
Any ideas what might be causing this?

08-30-2005, 09:47 AM
it rendered out okay here...
Hmm.. not sure!