By Tim Pfeiffer (Tbone) (68.15.139.25) on Sunday, February 02, 2003 - 09:12 am:

Could someone please help me out.
I need to show the flow of a liguid inside a pipeline with several 90° angles. Disolving away the pipe surface to reveal whats inside is no problem. I was wondering if there's a way to attach a null to the liquid surface somehow and pull it through the pipe where ever I want it to go? Straight on one axis is no problem but what about the 90° turns? Am I getting warmer?
I've modeled the pipe and the inside liquid seperately I just don't know how the animate it. Thanks for any suggestion.
Tbone

By Jason Hillon (Tumblemonster) (24.245.0.34) on Sunday, February 02, 2003 - 02:54 pm:

If the fluid doesn't actually have to come out of the pipe you could animate a procedural texture for the fluids surface. This way you don't need to alter any geometry or buy any fluid dynamics plugins (are there any for Mac Lightwave?).

-j

By Tim Pfeiffer (Tbone) (68.15.139.25) on Sunday, February 02, 2003 - 07:21 pm:

Yeh, thats what I thought I would do too. But I'm not having any luck. I have a pipe section that is just straight and then it has a 90° elbow and then goes up from there. This is just a schematic type animation to show how a liguid travels through the pipe starting at one end. It does not have to be realistic. I've tried using a null to drag the procedural texture but the pipe always renders all that color. I can't seem to control the second color. What am I doing wrong? Know of any tuturials for this?
Thanks
Tbone

By Tim Pfeiffer (Tbone) (68.15.139.25) on Sunday, February 02, 2003 - 07:24 pm:

I can't control the procedural texture with the null. I don't know what I'm doing wrong. Can you suggest any tutorials for this?
Thanks
Tbone

By Beam Tracer (Beamtracer) (203.109.241.109) on Sunday, February 02, 2003 - 07:42 pm:

I'd use particles. Trouble with Lightwave's particles it that they can't follow a path. The work around is to use wind to direct the particles (a clumsey way) or bones.

Alternately, you could spend some money and go to a 3rd party particle generator designed for tasks like this. Take a look at RealFlow:
http://www.nextlimit.com/productsrealflow00.htm

By Andrew Morgan (Aegisprime) (194.117.133.118) on Sunday, February 02, 2003 - 07:53 pm:

Funny you should mention this but I've just been working on a sewer scene and I needed 3 water channels flowing together to create one channel.



To do this I created a long, thin rectangle and texture mapped it with a fractal noise texture travelling down it on the Z axis. I then rendered this from directly above to create an image sequence of about 100 frames. Next I took the sequence and UV mapped it to another rectangle (this one subdivided). Using this technique I could bend the water channel to get the flow curling into the main channel. I repeated this process to create the third and final channel. I then blended all these sequences together to create an animated (repeating) bump map for my scene, part of which is shown below:



For ninety degree bends it should be even easier as you can just create one long UV mapped water channel and bend it into shape.

By Andrew Morgan (Aegisprime) (194.117.133.118) on Sunday, February 02, 2003 - 08:01 pm:

Alternatively, you can just map your procedural texture travelling down a single axis and create a morph target to morph a long, straight channel into your one with all the bends. This works because procedural textures conform to object morphs.

By Tim Pfeiffer (Tbone) (68.15.139.25) on Sunday, February 02, 2003 - 09:28 pm:

Wow! thanks for all the help. Nice work.
But maybe I should re ask my question another way.
I need to actualy show the liquid starting at the begining of the pie and travel the length of the pipe with all its ups and downs and turns. Think of it more like a worm traveling thru a tunnel.
Got any ideas? And by the way...RealFlow is NOT made for us Mac people. Darn it! I'd but it if they did.
Thanks again for all your time and help.
Tim

By Julian Johnson (Julianjohnson) (62.49.23.72) on Monday, February 03, 2003 - 12:55 am:

Hi Tim,

If the tube starts empty and you have to show the liquid moving trough the tube then I'd go for morph through bone chain. Mark Dunakin has a basic tutorial here:

http://www.md-arts.com/sluggish.htm

Essentially, you can create a skelegon bone chain in Modeler that conforms to your path. Create a base object that sits at the beginning of the bone chain and a morph object that is scaled the length of the chain. Provided you have 'used morphed positions' checked in your bone panels if you morph the object it will stretch along the chain and follow the bone path. If you make the bone chain in Modeler conform to your path you need to remember to reset the rest rotation of your bones in Layout once you've used CVT Skelegons to bones. Alternatively, you can make a straight bone chain in Modeler and just bend it into shape in Layout.

Particles will follow a path if you use path wind. Here you create a motion path that conforms to your shape; create a wind object that follows the path and set it's type to path wind; position your particle emitter at the beginning of the path. Path wind only works correctly from frame 0, I believe. However, if you then use HVs to define the shape of your fluid then it'll take some time to iron out the metabally shape that HV surfaces can often exhibit - unless your particle count is pretty high.

Julian
The Mac Lightwave Resource Page
http://www.exch.demon.co.uk

By Wizlon (Wizlon) (194.176.153.162) on Monday, February 03, 2003 - 07:12 am:

Newtek's particles can follow a path, it works great, it's the option called 'path wind' and worked flawlessly for me recently.

By Phil Braaten (Phillydee) (4.46.195.174) on Monday, February 03, 2003 - 12:28 pm:

Model the pipe, flip the normals INWARD, then set an emitter at the mouth. For the simulation, just up the resolution of the simulation so you get more of an accurate simulation. You can also set interaction between your particles. Again, to see this, you have to first run the particle simulation.

By Phil Braaten (Phillydee) (4.46.195.174) on Monday, February 03, 2003 - 12:32 pm:

To get it to turn 90 degrees, you can have a collision for a group of particles. So, 1 set of particles turns 90 degrees, the other keeps flowing straight.

By Jon Baker (Jdavidbakr) (65.67.204.86) on Thursday, February 06, 2003 - 09:25 am:

I'll echo Wizlon's comment, use a path wind. Then, for the split, you just have two path winds with different groups, and two particle generators, one for each group. Path wind is really cool - I also recently discovered this.

-Jon Baker
http://www.catalystproductions.cc/screamernet

By Howard Margolius (Howardm) (67.40.149.70) on Monday, February 10, 2003 - 11:39 pm:

Where is path wind?

By Howard Margolius (Howardm) (67.40.149.70) on Monday, February 10, 2003 - 11:43 pm:

nevermind!
Wow, never noticed it, thats a great tool!!

By W Wade Woehrmann (Thewww) (67.66.51.245) on Monday, February 10, 2003 - 11:48 pm:

Nice stuff all around so many options to get it done!