Falling leaves with particle flow

[elliottsmith]

This is my first post so I hope someone can help.

 

I am using 3ds Max 2010 and am trying to animate the falling of dead leaves from a tree. I am using a tree brought in from Onyx, converted to an editable poly.

 

I havent used particle flow that much but have been able to get my leaves to emit from a source and tumble to the ground.

 

What I am trying to do is get the leaves that are already in place to fall to the ground and rest there, i.e, no emiting from a source.

 

I have thought that this may be made easier if the leaves werent one element, so I detached all leaves to individaul elements, but still can get it to work. I've also tried removing the birth operand as I dont want to generate leaves, rather animate existng leaves, but still cant get the effect I need.

 

I have looked through these forums and elsewhere on the internet but cannot find an answer and have just spent two hours on hold with Autodesk only to be cut off, twice!

 

I have attached an image of how my pflow has been created.

 

Thanks in advance.

[Devin Johnston]

I don't know the answer to your problem but I can tell you to not waste your time calling Autodesk they won't help you with this because it's not a technical problem.

[hughie]

Try starting the Emit Start as a negative number, that way the particles are already in place, and then animate their speed so they are stationary until you want them to fall, you will probably need to adjust the keys in Track View – Curve Editor so their speed and movement works out nicely.

 

EDIT - put the Emit Stop one frame later so the particals dont keep spawning

Edited June 17, 2010 by hughie
additional info

[jinsley]

are you doing this on a very large scale?

 

I have done this on a small scale (3 trees up close to the camera) with reactor, keep in mind that not every leaf should fall at once, I think in total I had 100 leaves falling with a wind force blowing them slightly so they didn't go straight down...

 

pflow works best with particle fx, etc. where something is being emitted... I think that reactor might work better for existing objects which you want to fall over x number of frames...

[JonRashid]

If the leaves already exist why are you using an emitter. Why not just use gravity, perhaps a little wind and if you have a good machine make the tree a collision object. This will allow the leaves to flutter naturally to the ground and no messing with spawn, life etc

[hughie]

Agreed, I think you might get a better result with reactor

I just did a quick test, the Particle speed is set when emitted and not animatable like I thought, so having them hanging in the tree first will be troublesome, unless you want to composite them in.

[BobM]

Have a look at this it may help

 

http://www.cgrats.com/leaves-blowing-in-the-wind-3ds-max.html

[elliottsmith]

Thanks for all your comments. I will give reactor a go and get back to you with the results.

[elliottsmith]

Here are the fruits of my weekend. It took about 16 hours to render and i've almost got what i'm after, so thankyou for all your helpful comments.

 

[NoisyMonk]

Very nice!

 

I know you said you weren't done, but I'll just mention this stuff just in case it hasn't crossed your mind.

 

To get a really great, realistic feel, you need a little more physics involved with scene. Very rarely in the real world, outdoors especially, is there no wind or breeze - however subtle, adding a little shuffle and sway to the leaves when they are still attached to the trees would greatly improve the realism.

 

Next would be the air resistance as the leaves are falling. Currently they fall more like stones (straight down), but a nice broad maple leaf like you have, would twist, twirl, and sway on their way down - just like a piece of paper. If you've got the time and equipment, grab some similar leaves and record them falling. Even if you do this in your home where there is likely much less air flow than outdoors, you'll notice the relatively extreme motion they make as they fall.

 

Hope this helps you out a bit.

Noisymonk.

[elliottsmith]

Yes I will be addressing those issues when I next have some spare time. I'll be adding some animated noise to the leaves to give the timelapse effect and will also sort out the shadows cast by the leaves I couldnt animate.

 

To get wind involved in the reactor bit, would you play with the X and Y params in the Havok rollout or put a wind space warp in?

 

I did try to get the leaves to float rather than drop, but I found that when I reduced the mass of the reactor leaves or reduced the Z axis gravity effect the animation got really large and would have taken a lot longer to render. Does anyone have any suggestions to overcome this?

[NoisyMonk]

Personally, I'd use a Wind or other space warp. Trial and error will likely get you the best results in the end, but make sure you read up on every parameter and undstand how they affect the Space Warp - don't just randomly fiddle with them. You may get lucky and find a tutorial for something similar aswell - falling leaves, falling paper, etc. Youtube has some stuff.

, and this could be a place to start, but I didn't watch all of it.

 

The leaves just need to sway back and forth as they fall, aswell as having their fall speed vary depending on their orientation - when the leaf is parallel to the ground, it falls slower than when the leaf is twisted and almost perpendicular to the ground. This will be tricky, and I'm not sure how you might accomplish it. Maybe a horizontal Gravity force that has an animated Strength param, that 'pushes' for x frames, and then pulls for x frames. This may work with some tweaking - again, lots of trial and error.

 

Good luck!

[nelpiper]

Your reactor scene looks nice but reactor becomes slow when you're sttrating to populate your scene with to much geomerty. PF is your best bet. If I understood correctly, you should set your deflector to stop when the leafs hit it. Also try to combine forces to create an organic motion. It sounds complicated but it's not. You can even get a cooler animation by combining to PF sources. Good luck.