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Konstruct
08-14-2003, 10:13 PM
so my scene involves tons of instanced trees. I created them by raining down tons of particles on my hills, which then take on the shape of a tree model.

the problem lies here, I have roads and such all over my hills, I don`t want the trees to grow in the middle of the roads,

so basically what I want to do is to be able to select all of the trees that fall into the road, and delete them,- can maya do this,


also I was wondering if is possible to make sticky particles? Everytime I rain my trees down on my hills, they slide down off of some of the steeper hills.

noxy
08-15-2003, 01:52 AM
I would suggest making a nurbs plane that closely matches your landscape, make a map that specifies where you want to emit, and emit the particles with no velocity. Then save initial state when you have suitable landscaping. Even better, you could use the particle tool and draw particles where you want trees, could be tough if you need a lot.
To delete existing particles, you need to go into particle component selection, select the particles you want gone, see what their id is in the component editor, then make a creation rule such as:

if (id == 24 || id == 685)
lifespanPP = 0;
else
lifespanPP = 50;

Noxy

Originally posted by Konstruct
so my scene involves tons of instanced trees. I created them by raining down tons of particles on my hills, which then take on the shape of a tree model.

the problem lies here, I have roads and such all over my hills, I don`t want the trees to grow in the middle of the roads,

so basically what I want to do is to be able to select all of the trees that fall into the road, and delete them,- can maya do this,


also I was wondering if is possible to make sticky particles? Everytime I rain my trees down on my hills, they slide down off of some of the steeper hills.

Jozvex
08-15-2003, 02:40 AM
Originally posted by noxy
To delete existing particles, you need to go into particle component selection, select the particles you want gone, see what their id is in the component editor, then make a creation rule such as:

if (id == 24 || id == 685)
lifespanPP = 0;
else
lifespanPP = 50;

Noxy

Well, a slightly easier way:

1. Set your particle lifespan to 'lifespanPP only'
2. Right click on the particles and enter component mode
3. Go to Window > General Editors > Component Editor
4. Find the 'Particles' tab, then find the 'lifespanPP' field

Now you can just select particles in the viewport and type in 0 for their lifespanPP in the Component Editor. They won't vanish though until you change frames on the time slider.

And as for sticky particles, select either the particles or the terrain and in the Channel Box open up the 'GeoConnector' input/output and set the 'Resillience' value to 0.

Now they should stick.

:thumbsup:

Konstruct
08-15-2003, 07:15 PM
awesome, its going to be alittle tedious, but it`ll be worth it.

k, now my last problem that I can`t seem to fix is getting my particles to stop shifting around.

I`ve deleted all of the fields, set an initial state, and yet they still seem to slide around a little bit, Y?>:hmm:

Jozvex
08-16-2003, 02:17 AM
Well, setting the Initial State just says that you want your particles in that position on your first frame, but they still all have their momentum that they had before. There's two ways to fix it:

1. Select the particles and set their Conserve attribute to 0. That basically says for them to only move when they're acted upon by fields, or basically "Conserve = How much momentum do they have".

2. You could go into particle component mode, select all the particles and use the Component Editor to set their Velocity vales to 0.

:thumbsup:

anthonymcgrath
07-13-2005, 10:45 AM
hmm - I've had a bit of probs with this mainly cos I'm using the sprite wizard to offset an image sequence and it wont let me change to lifespanPP - gutted as this solution would work a treat. Just gonna have to try the script above :(


*edit - script above josvex dont work - based on lifespanpp - gutted.

akewt
07-13-2005, 01:07 PM
i wouldn't create forests and foilage from instances by 'dropping' the particles onto a surface. its a hell load more controllable to emit from your ground object and paint maps. i have created great foliage like this. using maps for the mountains and stuff i was able to make tundra and bushes that crept around the cracks and canyons of the mountain. fantastic!!!

copy the ground object and make emiter from it. UV it and paint a map to define where the foliage goes. emit with no speed untill you have the right amount. set initial state and dlete its emiiter. you have to put the instancer in there somehwere and you may want to have standins in a hierachy so emitting dosent grind to a halt.

if your using cards as well theres a great tutorial somewhere about getting your cards to actually use lighting and give shadows! i just rendered cards with ambOcc and hoped it passed. :S alright if your lightrig is static.

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