Snow particles

argus1000

I bought a scene by Magaremoto that displays snowfall on a mountain, a tree and a rock. However, I added a car to the scene. (pic 1)
The scene is 20 seconds long. At about 15 seconds, the snow from a particle emitter has fallen on the mountain, the tree and the rock, but not on the car that I added. What am I doing wrong? How can I make the snow fall on the car too? I added Magaremoto settings.Thanks.

evilproducer

Is it possible to link to the product page, so that people here can read the description?

I can't say for sure, but I doubt the snow on the mountain, tree and grass is from the particle emitter. The effect may be shader driven (especially the terrain.) Nearly everything in Carrara can be controlled by key frames. I think that you are looking at various effects timed to work with the particle emitter. If you look at the settings for the particles, the Die On Impact checkbox is checked, which means as soon as the particle hits an object, it's gone.

argus1000

evilproducer said:

Is it possible to link to the product page, so that people here can read the description?

Yeah. This is possible. Here is a pic of the browser settings (pic 1) and a pic of the product's description. (pic 2)

Frank__

Could be wrong, but in your picture 4 (advanced settings): "collide with scene objects" should be checked. And if doing this you have to change the basic particle setting to "Free in the scene".

It will not build up to some volume, but a least the snow should lie down on the car.

edit: and of course what evilproducer said: die on impact will not help :)

argus1000

I tried all those options. Did not help.

evilproducer

argus1000 said:

I tried all those options. Did not help.

You may need to look at other options, such as key framed shader functions to make snow on the car or modeling snow with morphs, so that you can key frame it's coverage.

Frank__

argus1000 said:

I tried all those options. Did not help.

I had these settings working with some cherry blossoms falling down and lie still for a still picture (after some animation pre-run to let start and settle down the particles) Shouldn't be so different. Carrara 8.

edit: And after reviewing my post: at DAZ: fix those picture dimension scaling in the forums, so some values could at least be read. Or, for something completely different: publish a comprehensive manual.

argus1000

Thanks, guys, but I'm still mystified by how did Magaremoto make the snow STAY on the mountain and grass (and he had "die on impact checked!") and that snow won't stay on the car I introduced. I'm baffled by this mystery. .
I know now it had to do with keyframing the shaders, but how?

magaremoto

hello Argus1000,

I apologize for the delay. The snow that I have created is a big bonfire slowed down and stretched out, as you can see; if you want to see the snowflakes on the car theoretically you have to uncheck "die on impact", increasing significantly the number of particles/sec and their size. I have post some shots where you can see some changes to let you see the particles that accumulate on the ground. Moreover I added two other shots to explain that the effect of snow on objects is given by the transition over time of similar objects that are deformed (slightly bulged), appearing and disappearing simultaneosly. in the case of the mountain and grass as well, the transition is at the shaders level. However, I'm going to do some more tests in depth ASAP

argus1000

Thanks, Magaremoto, for answering. What I really want to do is have snow falling and staying on the ground of a small village (see pic), on the streets, the rooftops and cars, maybe also the tree branches. It is not necessary that the snow be falling (though it would be nice), but it is necessary that snow be on the ground. Do you think its possible, considering the size of the set?

Milo

Not really being experienced, you can though you might have to approach it by in the time line adjusting shaders for snow on the buildings cars etc.

3DAGE

Hi Argus :)

Many things are possible,. but this particle effect, Snow falling on objects and creating volume in Carrara isn't practical, since the number of particles required would me huge and that eats up memory. and that slows things down.

Also,. remember that particles in carrara have no volume,. that's why you can't fill a glass with liquid (meta-particles),
So,.. you need to fake it another way.
you need to create a Volume which can rise, and make it look like the particles are creating that volume.

Magaremoto has used animated shaders, and possibly secondary objects "duplicates" (I think), with different shaders, animated to rise-up, to create the volume , and the "snow" particles simply add to the illusion.

Try a simple test scene with a cube or a plane, and a particle emitter.
no matter how long you run the particle emitter, and no matter how long the Lifespan of the particles, they will simply lay flat on the surfaces, they will not create a thick surface as snow would in real life.

If you create a fake "snow" surface which can fit under the model you have, then you could animate that to rise up as the snow is landing, then the illusion would be the same.

Hope it helps :)

magaremoto

3DAGE said:

Hi Argus :)

Many things are possible,. but this particle effect, Snow falling on objects and creating volume in Carrara isn't practical, since the number of particles required would me huge and that eats up memory. and that slows things down.

Also,. remember that particles in carrara have no volume,. that's why you can't fill a glass with liquid (meta-particles),
So,.. you need to fake it another way.
you need to create a Volume which can rise, and make it look like the particles are creating that volume.

Magaremoto has used animated shaders, and possibly secondary objects "duplicates" (I think), with different shaders, animated to rise-up, to create the volume , and the "snow" particles simply add to the illusion.

Try a simple test scene with a cube or a plane, and a particle emitter.
no matter how long you run the particle emitter, and no matter how long the Lifespan of the particles, they will simply lay flat on the surfaces, they will not create a thick surface as snow would in real life.

If you create a fake "snow" surface which can fit under the model you have, then you could animate that to rise up as the snow is landing, then the illusion would be the same.

Hope it helps :)

that sounds correct in my experience. All you have to do is playing around with two shaders, one that gradually takes over another, with the object slightly swelling out thanks to the bulge modifier (i.e. take a look at the terrain behaviour all the time Argus1000) or make a duplicate of an object, invisible first and getting visible, white and puffy afterwards (i.e. the snowy ghost rock); in this particular case I added a a noise deform modifier to better control the swelling along the Z axis, mainly, and get a more realistic result. feel free to ask me for any further help.

attached is the link where I have put two clips showing the effects you can achieve with my product

http://www.mediafire.com/?b73132jbjcx23n1

argus1000

Thanks, Magaremoto and 3dage, for the expert advice. However, I'm just a novice and can''t make the snow stay on the ground, however much I try. And keyframing shaders the way you do it is beyond my level. So I used a terrain shader (snow) for the streets and the rooftops. Carrara had great terrain shaders. Too bad the particle emitter is way too slow for a big set and animation. I would have liked to see the snow fall.

3DAGE

Nice work Argus1000 :)

the terrain snow works for me,.

What you should do is go to the shader you've made and set a couple of key-frames for the snow.. one at the beginning and one when you want to have that effect or more.

Then go to the start of your animation and edit the shader at the first key-frame point,
to take the distribution of the snow back to nothing.

Then when you play the animation, it should change from nothing to full on snow.

Now, you can add the particle snow effect, and have them "die on impact". which should render quicker than having them landing on the surfaces.

It's not an easy effect to do well,. and you've made a great start. :)

You could also consider having a small particle emitter "just in front of, and above, the camera" . which could have heavier snowflakes.

It's a bit like the effect you sometimes see in old films, where there's a burning building scene. and some of the flames are right in front of the camera.

It's done by having an assistant holding a burning stick in front of, and below the camera,
which creates the effect of being close to the danger,.. and keeps the camera operator safely away from any real flames in the set..

:)

magaremoto

for what I can see you should also take a close look to the "bottom" object in my scene: its shape and shader behavior over time should work fine for your roads and roofs; you might import my cubic particle emitter in front of the camera and change triangular flakes into spherical ones (beware to size proportions as specified in my T&T file); for trees: group and duplicate the branches and make them a bit taller. then following 3dage hints you may succeed

argus1000

I finally succeeded in placing my particle emitter at the right place. Thanks to your tips, I placed it right in front of the camera . Because the emission cube was small in size (5x5x5 ft), the scene could render pretty fast (1 frame a minute).
The snow is now falling and it is beautiful!
I haven't played yet with shader keyframing and noise and modifiers settings. That will be for later. You guys have been a great help!

http://youtu.be/tv3vV07uoiI

magaremoto

I love your urban settlement, are you planning to put it on sale? I could use for my works
about snowfall, try to speed up the velocity a little and make snowflakes a bit bigger, maybe you should act on their lifetime too

argus1000

magaremoto said:

I love your urban settlement, are you planning to put it on sale? I could use for my works

Be my guest. I got this nice FREE sleepy oceanside town from Google's 3D Warehouse. Of course, I added the lam posts and the lighting::
http://sketchup.google.com/3dwarehouse/details?mid=5dfa4f0d4ce2525b130f036c787f6884&prevstart=0
For the close-up of the falling snow, I used a house I built with McLean's Home One tools:
http://www.daz3d.com/shop/room-creator-exteriors/

In case you don't have Sketchup, I converted the set to a .3DS version that I used to import into Carrara here:
https://dl.dropbox.com/u/11970483/Beachport.zip

magaremoto

just picked up the skp version. looks very good. thank you