Particle Don't Inherit Velocity

[Rafal123]

hi,

I got an object in H, through Collada, which is animated and goes in X direction. I use it as a source for particles. When object moves it emits particles but they stay in this object local world. I've tried many options in source also tried to add velocity and point in geo but it doesn't work.

Check this and try to emit from any car's part:

www.rafal.stnet.pl/collada.zip

Can anybody help?

[edward]

Without either providing your Collada file or locking all your File SOPs, it's hard to see what's going on. But anyhow, this doesn't sound like it has anything to do with Collada. Why don't you try a simple example with some keyframes at the object level.

[Visual Cortex Lab]

yeah i also tried to open it up (during a meeting.. figure:p) but its missing of the DAE file which makes hard to understand the problem

cheers

[Rafal123]

ok fellows,

check it out:

http://www.rafal.stnet.pl/car_collada.zip

there are 3 files:

car.dae

floor.dae

my_cam.dae

use my_cam as a main camera and then try to emit particles from car

p.s

fellows, I think I found something but I'm not sure is that right solution... If ya got some time please do something like that --> go into MAIN node --> create there SUBNET and go into --> create GEO --> create POP and go into --> now use SOURCE here

use groups on tires

looks not bad with one exception.... particles born in some 'bunches' , what to do to make some continuity in their birth?

[stevenong]

Since the car animation is driven by nulls at the object level, you have to use an Object Merge to read the animation to the SOP level.

Create a new Geometry Object and a Null which you can rename to World. Go into the new Geometry Object, put down an Object Merge SOP, point the Object 1 field to the car File SOP and set the Transform Object to be /obj/World.

Next, you can append a Trail SOP to the Object Merge to compute velocity, if needed, else connect a POP Network SOP and sim away!

Hope the above helps!

Cheers!

steven

[Rafal123]

hey Steven, many thanks for answer I must check that

----

I also found something strange with emission. Check it out:

http://www.rafal.stnet.pl/car_emission.jpg

I emit here from the whole car geometry but it looks like 'stamping', geo emits particles for every frame, any chances to emit particles also 'between' frames? I thought this is something with playback but I have it set to "play every frame"

[stevenong]

The stepping/stamping you're seeing is due to the distance the car has travelled from one frame to the next. You can turn on Oversampling in the POP Network SOP to have the particles birth between frames which will fill in the gaps. Be careful with Oversampling as the sim will have to be calculated as many times.

BTW, I noticed in the animation channels is it starts from frame 2 or 3 so you'll notice a bigger gap between particles at the start.

Other than the above, the car animation looks cool! I'm very interested to see what you come up with.

Good luck!

Cheers!

steven

[Rafal123]

The stepping/stamping you're seeing is due to the distance the car has travelled from one frame to the next. You can turn on Oversampling in the POP Network SOP to have the particles birth between frames which will fill in the gaps. Be careful with Oversampling as the sim will have to be calculated as many times.

hey Steven many thanks, this is it, now it works ok

Other than the above, the car animation looks cool! I'm very interested to see what you come up with.

you must wait till I finish the reel (soon...), I wanna use Houdini for this project to create dust, sand, debris, particles stuff