Butterfly Tutorial: Using Item Motion

Part 1: Using Sub-Objects | Part 2: Using Item Moton

By: Anupam Das

Requirements:

Particle Storm 2.0 Pro and LightWave 5.5 or higher.
Sample Content location: Tutorials/PStorm2/Butterfly/

Basic Overview:

Instead of using sub-objects, you have another option. You can use the Item Motion plug-in, which allows you to add motion to any LightWave item. The benefits of using item motion is that you can use fully animated objects. If we wanted the butterflies to flap their wings while flying, you cannot use sub-objects. You must use the item motion plugin. This tutorial shows you the best way of doing this.

Initial Setup:

Firstly, you'll need the wings of the butterfly to flap and loop continuously. We've already done this for you. At this time, please load the scene: butterfly_flap.lws.

Notice that the butterfly object has been separated in to its wings and torso. Each wing was keyframed and the frames set to loop.

Go into the Scene Editor, notice the hierarchy. There is a NULL object that serves as the master parent to the butterfly. If you move the null around in layout, you'll see that the entire butterfly moves with it.

This was done for one simple reason; we'll be applying the item motion plug-in to the null object instead of the butterfly. This way, the animation of the butterfly remains completely independent of Particle Storm data, the item motion plug-in is only applied to the null object. When the item motion plug-in moves the null objet, the rest of the butterfly goes along for the ride.

Cloning the butterflies:

Hiarchy of Objects
We'll want a few butterflies to be flying around, so we'll need to clone the butterflies and preserve the hierarchy. The only way to do this in LightWave is to do a Load From Scene multiple times.

1. Go to the Objects panel and do a Load From Scene, select butterfly_flap.lws. Do not import the lights.
2. Repeat this for as many times as you want butterflies. For now, load from scene about 10 times. We'll work with about 10 butterflies.
3. Go to the Scene Editor, notice the clones of the butterflies we've made, and they all have their respective hierarchies preserved. This is good!
4. Back in layout, it seems nothing really has changed. Actually, the butterflies at this point are sitting exactly on top of each other, they're not flying around yet.
5. Save the scene.

Recording the Flocking data.

1. Load the scene, butterfly_flock.lws. This is the same scene we used in the previous tutorial.
2. After having the scene loaded, go into particle storm and load flocktut2.prj. This is the project file we created in part one.

Warning: If you do not load the scene first and load the project, your animation settings will be wrong! This is because the project references layout items, and we must have this scene with these items loaded in layout before loading the project otherwise it will not fine the necessary objects.
3. Select the butterfly particle group and change the Particle Type to points.
4. Select an effect file base for the particles, name it ButterFly_Motion
5. Now record the particles. Hit rewind, press the record button, and then press play. Sit back and enjoy the show. A file called ButterFly_Motion.psm should now exist in the directory that you specified.

Defining the Motion using Scene Info:

The scene info panel with PSM file loaded
1. Load the butterfly_flap.lws, this is the scene we had previously saved out with our 10 cloned butterflies. Now we'll need to apply the item motion plug-in to each of the butterflies.
2. Go into Particle Storm and select the scene info tab.
3. Click on the Load button. Information about the contents of the currently loaded scene will be displayed.
4. Select all the NULL objects by simply clicking on them (remember, these are the objects that we are going to apply the item motion plug-in to)
5. Right click on Item Motion Plug-in and select Add Plug-in.
6. You have now associated an item motion plug-in to each of the null objects.
7. Click on the Save button. This will update the scene info data in the currently saved scene file.
8. Exit back into layout. Re-Load the scene. You must re-load the same scene so that LightWave is aware of the newly added plug-ins.

Warning: Do NOT save the scene back out before re-loading. If you do, all the data that was written to the scene file during step 7 will be overridden. Particle Storm has actually mofied the scene file, but not the current state of layout. So this is why you need to re-load the scene.
9.Once the scene is loaded, select one of the null objets. Go into Graph Editor, and select Motion Plugins. You should see an item motion plug-in applied to the null objects. This should be true for all the nulls you selected in Scene Info.
10. Go back into Particle Storm and Select all the null objects. Select Particle Storm from the Plugins list.
11. Now you have to load an effect file to affect your particles. So, at this point load the ButterFly_Motion.psm as the effect file.
12. Click on the Enumerate button. This makes sure that a unique particle is mapped to each object, so no two objects is controlled by the same particle.
13. Now set the Effect Start Frame to 0 and the Effect End Frame to 450 (or at what ever frame you want the particles to stop).
14. Exit out of Particle Storm (you no longer need to do a 'save' within Scene Info any longer).
15. Scrubbing the frame slider forward, you should now see some flying butterflies!

If you'd like to see a scene that is already done, load butterfly_flap_cloned.lws from this tutorials content directory.