[Steve Bentley]

If you look in the Content browser of C4D you will find a preset under TP for water on a surface.
That will just generate the “points” of particles so you have to give the emitter an object to emit. For Metablobs you need a polygon with one point to be used as the particle object. (we used to be able to use the empty poly object but that doesn’t seem to work any more.)
To make a poly with one point, add a poly object, make it editable, move the center axis to one of the point positions, then delete all the other points. Now you have a single point with the axis at its center.

Play with that project to get a feel for how Expresso and TP works.

Because you have R14 I can’t send you a file (I’m on R19). So I’ll describe the set up for a simple splash.

Start a new project

Make a tube. Make it editable. Remove all the bottom points so you have a flat disk with a hole in it. This tube will be the ring of water that erupts during the splash so set the wall thickness appropriately for your splash size.

Make a null.
Add an expresso tag to the null. In the expresso window right click and pick from the list to add the following: TP PMatter Waves node, add a PGroup node, add a pShape node, add a Constant node add a PPass node, add a Pgravity node. You can arrange them as needed at any time.
Anytime you click on a node you can see its attributes and slots to drag things to in the attributes menu. You can also click on the top right and top left (blue and red) boxes in each node to add ports to either the input or output side – the ports available are listed when you click. The ports will show up along the side once you select them (you may have to make the node bigger to see them all)
( a little note here – when I say “drag”, select a node in the expresso window first and then you drag an object from the object list to the attributes panel of whatever node is selected. For Connecting, you drag the output of one node’s port to the input port of another node in the expresso window – it will connect with a little “wire”. Outputs on nodes are always on the right, inputs on the left)

Connect the Constant output to the Rate input on the PMatterWave node. Set the Constant nodes value to 500. (there is a bug in some versions – normally you can set this in the pMatterwave node without connecting a Constant node but this Constant technique is much safer)
Connect the PPass Particle output to the Particle input on the Pshape node
Connect the particle output on the PmatterWave to the particle input of the Pgroup node.
Don’t connect the gravity just yet.

Add a Particle geometry object from the simulation menu.

Click the Custom menu in the Xpresso window and select Thinking Particle settings. That will open a little panel. Select the particle geometry object in the object list and drag the “All” word from the TP settings you just opened (just below particle groups) to the particle group slot in the particle geometry object’s attributes. Do the same for the PGroup node and the PPass node.
The idea here is that you are outputting the particle from the Pmatter emitter into a container called pGroup and the name of that container inside the Pgroup is “all”. Then you feed the pShape node and the Pgroup node and the particle geometry object a link from that container.
TP goes through each particle it finds in that container and decides where to send it and what to do with it.

Add a metaball object from the Modelling menu.
Add a polygon object and make it a single point as outlined above.
Select the Pshape node and drag the single point polygon into the slot that says Object.

In the PmatterWave attributes set the Birth type to Rate, set the speed to 600 and set the speed variation to a random amount (the higher the number the wider range of different speeds you will get, to a max of twice the set speed). Set the direction variation to 50 – this makes the splash have a v shape – it varies the angle the particles emit at.
Drag the tube object to the Object slot in the Pmatter waves node.

Rewind you time line and hit play. You will see little crosses leap out from the tube traveling upward and spreading out.

Make a key frame on the constant node value at frame 5. Then at frame 15 set the value to 0 and keyframe again.
This will start the spray of particles at 500 points that will taper off after frame 5.
Adjust the speed in the PMatter waves node and angle, and the Constant node values until you have the kind of spray you want.

You can connect the output of the PPass node to the particle input of the gravity node (we’re sending the particles in the “All” container we want gravity to affect to the gravity node). Add an object to the scene (any object). Make its z axis point down. Now drag this object to the Gravity node’s object slot. This object tells gravity which way to move. Set the gravity node strength to 300.
Play with this number and the speed to get the look you want for the splash spray.

Set the Metaball Hull value to 500 and the editor Subdivisions to 50. Go to frame zero and make the particle geometry object a child of the metaball object. Turn the exponential fall off to ON in the metaball attributes.

Hit play. Play with the setting in the metaball object to get the look you want.
The hull value: small numbers make smaller more distinct blobs and the points that generate these blobs have to be closer together to coalesce. Larger numbers make the blobs join easier and at farther distances but you get a rather indistinct giant blob. Its tricky.
The smaller the editor subdivision number the smoother the blobs will be. The lower the number the more processor intensive it is. There is a render subd number so that you can rough it out in the editor and then when you hit render it uses a smaller number to divide up the blobs smoothly but it can take lots of time to render.
Make the tube invisible to the render (bottom stop light on its object)

Let me know if I’ve missed anything. I can read your project and let you know if you’ve done something wrong or suggest better settings.

[Steve Bentley]

Depending on realism level you can easily use the meta blobs in C4D to simulate a splash and drips. Use a standard emitter or TP to emit particles (but no geometry) and then attach the metablobs object to that emission. As the generated spheres get close, they coalesce just like water does. A good transparent shader with the index of refraction set to 1.3 and reflections of the environment will sell it pretty well. Motion blur is key here too.

For the water dripping its best to use TP and have a surface position set by the Surface Position node and the SetData node or use mograph. Its usually best to animate the effectors (to make the water appear to roll down the surface) manually or animate the position offset of the surface position node manually.

You can of course use Xparticles or Real Flo to take it to the nth with photorealistic results but both of these are expensive (and worth it) but for these kinds of quick things you can usually do it natively. I’ll bet in the end, the C4D water will look more real than the alligator.

[Steve Bentley]

Sorry for the delay. Did you solve the hud?
You can put a Result node in the expresso that is fed by your switch for the List chooser. In the attributes for that Result node, add a User Data element that reflects the output (probably Float and Real instead of the default percentage). Say ok, then select the new User Data tab that has been generated. Now drag the little sprocket icon at the top left of the attribute panel into the Expresso window and hook up the output of the Switch (the same one that is still connected to the Result) to the User data input of the new dragged in node (it will also be a Result).
Now in the Attributes of that node, right click on the Data in the User Data tab (beside the value) and say Add to Hud.

[Steve Bentley]

In the new AE you can now access data files to generate graphics. Whether you have a midi file or a text based notation of your music will change the pipeline here but both of these are convert-able to something that AE can understand.
I’m not sure a particle system would be the best though. It might be better to (if you want to do this sort of thing in AE at all) to write a script that has Classes. A master note Class and then inherited classes for whole notes, quarter notes, sixteenths etc. As AE steps through the data file, it would generate the correct solid for whatever kind of note it finds and that solid can be told to descend the screen at a constant rate. You can use position and size parameters in Expressions to trigger which key lights up in the bottom graphic.

You can also do this all manually of course but depening on length of song that could become a life sentence.

If it doesn’t actually have to match a piece of music and its just something like your example, and you still want to use particles, you can have a Particular emit a random shape (from a precomp of a group of specific shapes) and have a collider mask down where the keyboard is. When the particle hit that mask they will generate another particle that “lights” up that key.

[Steve Bentley]

While not ideal, and not within the “workflow”, pshop’s “paint on video” tools have really grown up of late. It’s not perfect but better than no solution at all in AE.
There used to be a CC paint that got a little slow with many strokes but it could paint in the viewer. I’m not sure if it still exists or not (or why adobe didn’t roll it in when they rolled all the other CC effects in for free – oh wait, I remember CC paint being very big for what it did. So maybe AE’s waistline was already hanging over the belt too much.
There may be a third party effect you can add on at AEscripts.com
This is long overdue. Usually I switch to Flame or Nuke when I need to do this.

[Steve Bentley]

I’m wondering about the OP’s experience level. The render cue has been there since…. well since I can’t remember when; maybe as far back as COSA.
And the cue has nothing to do with render size. In fact its where you set render size for final output (Full size, half of comp size, custom etc). Perhaps the OP is just letting the standard settings ride without changing them and with the new install of CS6, his copy of CS5.5 went back to the default of Full size (of whatever his comp is) and full quality, when he had been rendering everything at 1/4 rez maybe?.
Compressing H264 out of AE is not the best pipeline. Sure it makes smaller files than uncompressed but you don’t get two pass compression which can drastically improve the quality and shrink the size of the final file for the web.
I think thats probably what Michael meant instead of “H264 is buggy as a QT format”. H264 in a QT wrapper kind of built the video experience on the internet since Sorenson. So, compressed correctly, H264 QT is just dandy.

[Steve Bentley]

It’s not so much the particle effect that’s triggering the keys, it’s the musical notation triggering the particles. There’s software for this but you can do it in ae. More later.

[Steve Bentley]

Thanks again for that insight K. I was able to change all my Z scales (which truly don’t matter on flat planes) to maatch the X values, and linked all my children in a cascade which resulted in no scale or rotation changes.
You’ve saved the day again!

[Steve Bentley]

Thanks K. That sounds like they are using a sort of 2D scale calculation for inheritance (y’know, without the Z).
I’m so used being able to parent to add a slight change to an already stellar motion path of the child without disturbing the child in AE that I knew something was up, and because it stands out against C4D’s version where the parent must be either at frame 0 or at the origin, otherwise the PRS of the new parent and the child combine to fling the child somewhere off screen.

[Steve Bentley]

Thanks for that Andy. I’d forgotten about that pref file.

I had a heated (in a good way) conversation with Piotr about premult vs straight when the spec was first being born but I’ll review it again now that I have more or less gray (hair and brain cells respectively). I’ve always railed against the “norm” of the premult alpha in the industry given that anytime we were having a matting issue I could solve it by working in a “straight” pipeline. But I’ve given up yelling into the wind; it seemed for a while I was the only one that cared or knew.

One of the questions I ask my new hires is: What’s the diff between straight and premult? – to date I have yet to have anyone answer that question correctly (and I don’t even want the math/techie answer); most don’t even try.
I think perhaps VFX has gotten to compartmentalized, due probably to sheer size of projects, and that kind knowledge gets lost by all but the TD’s. And in some ways that takes some of the fun out of it.