Difficult Particle & Texture Question

[Brett H.]

Larry Schultz (SplineGod) showed some really cool examples of fluid spattering on a wall and dripping down (I believe he used HyperVoxels) but he never explained how he did it.

I know it can be done with some experimentation with HV's and the wall as a collision object, using a negative gravity on the Y (envelope it to increase as the particles splatter).

Oh, and shaders tab is in the image.

Brett

[Remi]

Sticky wind...try that...it might work...:thumbsup:

[Willax]

I'm not real well versed on HV, but I would think attaching an effector to the wall object and making sure the life of the HV was long enough to maintain it's presence.

[Chagidiel]

Hmm... not sure I got your wish right, but here is a suggestion.

It is a kind of tough setup if you are unexperienced with particles and collusions and such, but I take it you have some knowledge about it. The manual might come in handy to do the correct tweakings. Post again if you don´t know how I mean and I may make my suggestion more detailed.

But here we go:

Add an emitter to serve as a "base-splasher" for whatever it is you want to splash. Assign NO hv´s to this dude.
Setup the splash-thing the way you want it against a collisionobject, with gravity or vector-influence or any other way you might want to set it up.
Imagine the particles from this emitter as "lead-drops" that will have a trail of drops coming after them (and they will).

When you have arranged this in a way you like it; add another emitter. Parent this emitter to the first one and set the nozzle to "parent emitter".
This will make the particles frome the base-splasher to serve as multiple little emitters and, as they move, leave a trail of particles behind them.
Here is the really hard part; to tweak the settings on the second emitter. A few quick suggestions are;
- make the startframe fixed (to the frame where the base-splashers particles hit the collision.
- make sure the particle limit is kind of high.
- set "generate by" to frame and have a somewhat low birthrate (depending on how the fast/slow the base-particles are moving of course) A value of 1.0 might do.

Then you might have to tweak the settings of the base-splasher as well, since their motions might appear different when a trail of particles is following them.

As you might have guessed, it is to the second emitter you should assign the HV´s. Make sure they have a gradient texture (particle age) controlling their size. They should be att zero size as they are born and increase to full-size in a couple of frames.

If you do it right it might look kind of like this:

[wgreenlee1]

Wow!

Thats cool Chagidiel,excellent tip!

[SplineGod]

Originally posted by Captain
Ok, I have run into a brick wall. I need to have a particle(s) with HVs (but that should be irrelevant) that leave marks on textures when they hit them. Such as blood splattering on a wall, or perhaps just a little wetness on skin (which might just mean an increse in specularity for affected area). How would I do this...I keep running into this word SHADER, but I really am fuzzy on what a shader is. Do you guys have a solution to my prob, or a workaround?

-Captain
You dont need hypervoxels. You can do this easily by applying a procedural texture to your surface but using a reference null to move the texture around. Make sure you apply fallof to the texture. As you move the reference null (or any object) closer to the surface the splat will appear.
To do multiple splats you could potentially generate a few particles and fxlink a few nulls to them. Copy your original splat procedural to multiple layers and assign each to a difference reference null.

[SplineGod]

Originally posted by Brett H.
Larry Schultz (SplineGod) showed some really cool examples of fluid spattering on a wall and dripping down (I believe he used HyperVoxels) but he never explained how he did it.

I know it can be done with some experimentation with HV's and the wall as a collision object, using a negative gravity on the Y (envelope it to increase as the particles splatter).

Oh, and shaders tab is in the image.

Brett
The splat example used no HVs at all, just textures (procedurals in this case but could easily be image maps) and reference nulls.

[Chagidiel]

eh... sorry, I have to correct some aspects of my earlier post.
I was rather tired when I wrote it :)

I said that no HV´s should be assigned to the base-emitter. Actually, I think it really should have HV´s, since this is the lead-drops of the splash. I also suggest to make the particle size on these HV´s somewhat larger than the size of the ones in the trail.

And if you assign HV´s to the base-emitter, you need to pay no attention to what I wrote aboud letting a gradient-texture controlling the particle size of the HV´s of the second emitter (since these particles are born inside the parent particles)

I made a little demo-render:

http://www.blodbad.nu/chagidiel/splash.avi

(divx 5)


hope I have not caused too much confusion

[Brett H.]

Chagidiel,
This is definitely an awesome effect, something I have a use for. Could you possibly explain it in a bit more detail, or provide a scene file? Sorry, but I've tried it the way you explain it and I'm getting really weird results. I love the way it splats and spreads in your example avi. I followed exactly what you said and I really am not getting the particles to emit from the "base emitter's" particles. Parent the usual way, as in "Motion Options", correct?

Anyways, if you have the time, I'd appreciate it.

Brett

[Captain]

Nah, My problem is a litle different. Anyone seen shreck? Rmemeber in the beggining of the movie when he was takinga mudshower, and as the mud poured over him, it changed his skin(the texture) when the particles toughed them. I don't want my resedue to be made of particles, but rather have the texture change....

btw, Chagidiel, that was a a really neat thing you did! I tried it myself, and I am quite enthused, and hope to use that effect soon!

-Captain

[Chagidiel]

Hmm.. Captain, I kind of get it what you want to do... but can´t really come with any suggestions unless you show exactly how your scene is looking and very in-detail what you want to do.
It all sounds like one of those setups where you have to use your MacGyver-force and solve the problem according to what you have at hand. There is no "global" effect for this kind of thing, that I know about.

Brett H.
Sorry... I know I wrote it all in a kind of confusing way and left out describing alot of settings that weren´t essential for the setup. I did not write anything about the collision-objects settings for example.
But I will list up all the settings in all the tabs for all the items and post them here. I presume I will have time for that tomorrow.

If there are more people interested I can write something more detailed about it.

[webfox]

Sounds like you want Surface Effectors (http://premdesign.com/surfeff.html)

His website doesn't show them anymore, but SE would do all the things you're talking about.

[freerider]

Hey Chagidiel.

That is a very cool effect. I think it would make a great tutorial! Hope you can write something a bit more detailed about how you created that effect :)

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