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Change size of particle cone
http://horde3d.org/forums/viewtopic.php?f=2&t=2307		 Page 1 of 1
Author:  Oliver [ 16.08.2017, 04:40 ]
Post subject:  Change size of particle cone
Hi,

how can I change the size of the particle cone? I can alter its position and
orientation via h3dSetNodeTransform but the scale values have no effect.
Author:  Irdis [ 17.08.2017, 18:43 ]
Post subject:  Re: Change size of particle cone
As far as I remember, it is regulated via h3dSetNodeParamF( emitterNode, H3DEmitterNode::SpreadAngleF, value ). Currently it is not possible to change the initial particle positions from the center of the emitter - they always start along the vector, where emitter is poiting, plus some randomness.

You can try different parameters and see the results in the editor that is in the develop branch.
Author:  Oliver [ 18.08.2017, 01:12 ]
Post subject:  Re: Change size of particle cone
Thank you for the reply, Irdis. I had no idea the editor works on
Linux - awesome!

The editor makes it is easy to reproduce my problem: load the
particle scene (particle.scn) and modify the emitter node
properties. "Position" and "Rotation" have the intended
effect but "Scale" does nothing except when set to [0, 0, 0].

I would like to use particles to render the exhaust "flames" for
space ship engines. Since capital ships have larger engines
than drones, I need a way to scale the "flame" as a whole.

Do you have any ideas how I could do that?
Author:  Irdis [ 18.08.2017, 15:18 ]
Post subject:  Re: Change size of particle cone
Do you mean that you want to increase the length of the trail? Then you can try to increase particle life via h3dSetResParamF( particleRes, H3DPartEffRes::ParticleElem, 0, H3DPartEffRes::ParticleLifeMaxF, 0, value );
Horde's editor allows modifying parameters of the emitter, but not the particle effect (maybe I'm mistaken, but I didn't find a way to modify them in editor). Therefore, you may have to modify the values in particle resource files. You may also take a look at ChanMoveVel (velocity channel) and its life. And you should probably check ChanSizeElem too.
Author:  Oliver [ 19.08.2017, 11:02 ]
Post subject:  Re: Change size of particle cone
Your suggestions regarding ChanMoveVel and ChanSizeElem are spot on. If I
adjust those parameters accordingly then I get the desired effect.

Below is a screenshot of the demo I hacked up. My "problem" was that all flames
had the volume of the top one, whereas I wanted the "small" one at the bottom.
Adjusting the particle size and velocity did the trick.

Thank you for your help.

Attachment:
File comment: Particle flames
flames.jpg
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