particles / tuhopuu update 17/04/2004 - testing help needed!

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leon
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particles / tuhopuu update 17/04/2004 - testing help needed!

Postby leon » Sat Apr 17, 2004 2:12 pm

hi all,

I've committed a couple of changes to the particle code:

1) Deflectors / attractors only affect particles emitted in the same layer
2) Fixed some of the deflection code so that leaking should be much less of a problem (but make sure that the normals of the deflector faces are facing towards the particles you want to deflect)

Here's the update Tuhopuu (just the exe):
http://reblended.com/www/leon/thp_pdef.zip

And here's some documentation on the particle stuff (just work in progress so far!!!):

http://reblended.com/www/leon/particle

Cheers

Leon
Last edited by leon on Sun Apr 18, 2004 1:12 pm, edited 1 time in total.

kencanvey
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Postby kencanvey » Sat Apr 17, 2004 4:59 pm

Thank you Leon for this work, the web site is helpfull too.


Ken :D

leon
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Postby leon » Sun Apr 18, 2004 1:11 pm

Cheers Ken!

Right, now we're getting serious!

I'm gearing up to submit the particle stuff to bf-blender. I've ported the code over to a copy of bf-blender, and I'll be submitting a patch to bf-comitters for comments and suggestions, probably tomorrow.

I'd be very grateful if anyone who has time could help out with testing - here's a bf-blender containing the particle code:

http://reblended.com/www/leon/bf-blender.zip

It's just the exe, so you will need to extract this into a copy of your existing bf-blender directory.

The functionality should be as described in the documentation link in my first post above - please post any bugs you find here.

Cheers

Leon

Monkeyboi
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Postby Monkeyboi » Sun Apr 18, 2004 2:28 pm

I'm having trouble with Gravity. In my oppinion it should so that the particles were attracted by faces, not vertices. With vertices it is hard to get a good even gravity effect.

theeth
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Postby theeth » Sun Apr 18, 2004 3:15 pm

Monkeyboi wrote:I'm having trouble with Gravity. In my oppinion it should so that the particles were attracted by faces, not vertices. With vertices it is hard to get a good even gravity effect.

I'm not sure I understand what you mean. Gravity is a positional force, it's not affected by the orientation of the source, using faces would just make it harder to tweak precisely.

Martin
Life is what happens to you when you're busy making other plans.
- John Lennon

leon
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Postby leon » Sun Apr 18, 2004 3:39 pm

yes, gravity is meant to be point sources....

On the other hand I can see what Monkeyboi means - it would be nice to have a face attract or repel particles. Not necessarily gravity as such, imagine something more like an electrically charged plate...

I think the maths would be slow though, but i'll look into it...

Monkeyboi
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Postby Monkeyboi » Sun Apr 18, 2004 4:02 pm

I was trying to do a simple scene with particles and some gravity. I placed a mesh plane set to Gravity under my particle emitter. Instead of the particles falling towards the mesh plane face, they were falling towards the individual points of the plane in the corners, and didn't look like gravity at all. That is problematic in my oppinion.

Do you see what I mean?

theeth
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Postby theeth » Sun Apr 18, 2004 7:04 pm

leon wrote:On the other hand I can see what Monkeyboi means - it would be nice to have a face attract or repel particles. Not necessarily gravity as such, imagine something more like an electrically charged plate...

I think the maths would be slow though, but i'll look into it...

I have formulas for that kind of stuff from Dynamica.

Monkeyboi wrote:I was trying to do a simple scene with particles and some gravity. I placed a mesh plane set to Gravity under my particle emitter. Instead of the particles falling towards the mesh plane face, they were falling towards the individual points of the plane in the corners, and didn't look like gravity at all. That is problematic in my oppinion.

The calculations assume ponctual sources of gravity. What you are suggesting is a gravity "surface". It could be done by calculating the closest point on a face and compute from there, but it would be much more computation heavy than using ponctual sources.

Martin
Life is what happens to you when you're busy making other plans.

- John Lennon

_styken
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Postby _styken » Sun Apr 18, 2004 10:01 pm

Isn't this two different cases we're talking about?

1) Gravity
2) Deflectors /Attractors

Gravity is depending on what scale we should use it in. If we use it at ground level we could approximate a infinite plane with a fixed normal to calculate the gravity force. This way we dont calculate to fixed vertices but towards the normal.
At planet scale we have a sphere that attracts bodies with different gravity force depending on distance to centre.

Deflectors /attractors should be calculated at face level, of course this would use heavy calculations (as discussed), but the result would be what we want! Or we could tesselate the mesh to achieve a good enough solution.

//styken

GFA-MAD
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Postby GFA-MAD » Sun Apr 18, 2004 10:28 pm

Again a great feature for Blender ! :D :D So I've take the time to test it !
This feature is cool and is well working.

The 'point' attraction is a good choice because it is well defined (law of Newton 8) ). Face attraction is more difficult to code.

At first, I told myself: "It's missing gravity". But gravity can be simply simulate by creating a small plane far away in the bottom.

So, this feature is OK. I hope it will be a full part of the BF-Blender (2.33 or 2.34 maybe ?). And count on me for bug reporting :wink:

Apollux
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Postby Apollux » Mon Apr 19, 2004 1:53 am

There is also a small fix to allow particle emitters to be parented to armatures.


Haven't test it because I'm on unix right now, but if it is true then that is not a small fix leon, that is HUUUUGE fix. :D

arangel
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Postby arangel » Mon Apr 19, 2004 6:31 am

Great features, Leon! Thanks!
Alexandre Rangel
Multimedia Designer
www.3Dzine.com.br

rafael
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Postby rafael » Mon Apr 19, 2004 9:08 am

Thank you very much Leon! :D
There are three kinds of people in this world: those who can count and those who can't.

wavk
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Postby wavk » Mon Apr 19, 2004 9:35 am

Hi leon,

Wow! I didn't know people were working on this. Suddenly the current particle system seems so dated.

Gravity setting is a bit awkward. The first time I got exactly the opposite of what I expected. But now it does work I guess.... Hm... I can't really get it to attract really to the points, it keeps going in weird turns.

The new panel now resides in the edit buttons, I think that's a weird place. Why not in the same place as the other particle buttons. I found that tweaking the particle system was very hard, because I had to contiuously switch between edit buttons and object buttons to recalculate the particles and tweak the particles etc.

That makes me think of the recalc button. Isn't that a bit ancient? I have the idea that when you press the button, it's a snap for blender to calculate it. Why not recalculate the entire system after each change that might have effect? I wonder how lightwave does it, lightwave must have the most interactive particle system around. You can just drag sliders while playing the animation and it updates instantly. Maybe it calculates per frame?

Also I couldn't get the nice results you have on your webpage. The deflector works very strange. More like a sin wave than a real

___ _____0
\ /
\ /
||

bounce :D

Well, good start and this can really become very powerful. Keep up the good work.

Maybe I set some settings wrong. But if so, that means that the system isn't very intuitive.

But this is really promising, very good!

ilac
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Postby ilac » Mon Apr 19, 2004 10:05 am

wavk wrote:The new panel now resides in the edit buttons, I think that's a weird place. Why not in the same place as the other particle buttons. I found that tweaking the particle system was very hard, because I had to contiuously switch between edit buttons and object buttons to recalculate the particles and tweak the particles etc.


Same thoughts over here too! These settings should go with next to the effects panel, please!


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