View Full Version : bottle with dropplets on that needs to fly off

Snake Eyess
01 January 2012, 02:03 PM
I have a bottle that I have put dew onto using Pflow (shape instance, position object, speed, speed by surface among other operators)

I need the bottle to now move into scene and stop and then some of those drops need to fly off and some run down the side of the bottle...

can anyone show me into the right direction (maybe a tutorial or some help)
I am willing to send the scene of what i have so far.

01 January 2012, 03:39 PM
Allan McKay has a dvd where he does more or less the same on a can of soda. He's using lock/bond and having them break off based on acceleration.

Snake Eyess
01 January 2012, 03:37 PM
i have seen that DVD and done the lesson.
problem is that I can get the sprits running down the bottle, but I cant get them to have a nice friction to some of them (slowly slide down then stop) and I need ALOT more than what Allan uses on that can, and I would like to see if I can get a few drops to "splash" off the bottle when it gets slammed down.

also, is there a way to get the sliding spritz to "catch" the stationary spritz on the way down... blob mesh maybe?

Snake Eyess
01 January 2012, 10:04 AM
I also have a displacement map on the bottle where there is a embossing effect on the bottle, i need the particles to take this into account, how would I?

01 January 2012, 11:20 AM
I also have a displacement map on the bottle where there is a embossing effect on the bottle, i need the particles to take this into account, how would I?

imo to make all these particles look like liquid you should use liquid solver (realflow, glu3d etc.)

as for displacement - assuming that you want to displace geometry only in rendertime you need to find nearest point on surface for every particle that sticks to it and find its UV coords and then find value of specified map (disp in your case) in these coords. then just offset particle in direction of surface normal in that point by some value [ ((maxOffset-minOffset)*(intensity-0.5) in case of 0.5-based displace]
i think it could be done with Box#3 or scripting.

as for "suckin in" nearby particles on bottle - let's assume you have Seed particles that travel down the bottle (using random walk for example) leaving trails behind. for each this particle you can constantly check for neighbours. as soon as two Seed particles are closer than some threshold distance you can send the one with smaller speed to another event, apply FindTarget op to it to chase the first Seed particle and then kill it as it reaches target.

it's all right out of my head so be gentle=)

Snake Eyess
01 January 2012, 02:14 PM
out of your head is alot more than what i have at this moment...

im not SUPER clued up on Pflow... so what you mentioned was a little over my noggin to be honest, but i will look into it

Snake Eyess
01 January 2012, 06:47 PM
ok, I need some MAJOR help in getting this scene looking right.

I have the "spritz" on the bottle but it still doesnt look real, or right even... the bottle looks diseased.
one reason i know is the lighting, the other is the actual particles...
could someone please get me on the right path.

The spritz sliding down the bottle isnt TOO important right now, but would be awesome to know how to get it to work right. Ran into another issue (other than it working properly) with the fact that the logo is embossed with a displacement map... Pflow doesnt take that into account so the drops wont go on or around the logo :(

This is a reference of a clean bottle:

this is a Spritzed bottle (the look i need to get)

and then this is my render O_O:

I am willing to send the scene to anyone willing to help me out. Wanted to upload it but cant seem to...
All help is greatly appreciated.

Snake Eyess
01 January 2012, 04:43 PM
ok, Resorted to just using object painter for the drops, renders faster and scene handles alot better.
STILL need some MAJOR help getting this looking right though.

please can anyone help me out :( im really in a bind

Snake Eyess
01 January 2012, 03:39 PM
ok, drops no longerneed to fly off, but i do need one to slide down the surface of the bottle.
I have one going down using to object surface.
initial spawn is on one of the vertices on the surface.

problem I have is that once the drop starts running down, it doesnt move with the bottle which is slowly rotating.

any one got any ideas?

01 January 2012, 05:59 PM
The simplest/best/efficient fix would be to move the camera and not the bottle. You will get 10x (or more) better performance out of pflow. The fact that pflow won't have to evaluate collisions and interaction with an animated object is huge ;)

Snake Eyess
01 January 2012, 07:57 PM Pflow that weak that it cant just stick to a surface??? Im half way there, its born from a vertice (which it sticks to) and then slides down but doesn't turn with the bottle...

unfortunately at this stage of the game, animating the camera isn't a option :(

01 January 2012, 11:01 PM
LOL I am sure some think it is. The thing is do you model something with millions of polygons or do you use what you need? I suppose if you do it often you use only what you need.

Back to topic, have you ever tried to rig a spinning object ON a spinning object? This is basically the same thing, you are working with transforms on top of transforms. The can lead to unexpected behavior, period.

The simplest most efficient solution, as I already mentioned, is to have only one transform being effected, the particles. Not the particles AND the bottle.

Here is a pretty simple similar setup. Compare the two systems in the attached file they are identical with the exception that one bottle is animated and the other is not. One will play in RT the other will not.

Snake Eyess
01 January 2012, 09:48 AM
I Hear you JohnnyRandom and do understand what you are trying to tell me.

Difference is that I am trying to only get ONE single drop sliding down, 99% of the spritz is geometry now (using object painter) not particles. So that already saves on computing power.
I have one particle born on a selected vertice, have it sliding down along the surface (using a lock/bond) it just isn't rotating WITH the bottle... thats all

01 January 2012, 11:47 AM
it will not update rotation while you are rotating bottle in viewport. animate it and hit play. all should be fine.

01 January 2012, 02:29 PM
i recorded a video tutorial for packshots a while ago for

you might wanna check this one out.

kind regards,

Snake Eyess
01 January 2012, 08:57 AM
Thanx for the file JohnnyRandom, and for the video tutorial there PsychoSilence.

could you maybe go a little more in depth on what that script test is doing Johnny?

01 January 2012, 07:26 PM
It is just taking a random sample of a random count of what particles are left over per frame. I was just messing around with a quick way to get "random" particles to pass to the next event. It could use a little more logic to make it a little more consistent, but hey :)

Snake Eyess
01 January 2012, 12:46 PM
ok, well, I cant seem to get this working

here is the scene with the drop running down the bottle, ( but its not turning WITH the bottle. If i do tell the drop to be Lock/bond onto the bottle, then it changes the behavior of the drop completely... Can someone take a peek.

01 January 2012, 08:14 PM
Be kind don't upload to a clean host ;)

Well, again, since you don't want to animate the camera, I suggest you bake the system (SuperMesher, Xmesh, might be able to Point Cache the particles if the topo doesn't change) and then link the cache to a helper that is parented to the bottle. That way it will match what you have set up. Since it is a commercial gig, I'll setup, cache, upload the reader mesh to ftp for a $100 (more than reasonable I think. Just to clarify SuperMesher Reader is free) or you can pick up a license for yourself of SuperMesher for $125.

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