Help with particle explosion

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
  10 October 2013
glad to help. Yes nParticles are vastly superior to vanilla particles, I rarely use the original ones anymore except in cases where I need vast numbers.

for this type of effect you should probably use a rigid solution for the larger non rubble type pieces. I mostly use instanced debris as small scale filler on effects like this, like little rocks to fill the explosive volume rather than the hero pieces. the spherical collisions are unfortunately all thats available right now but Duncan is workign on something that mimics rigid collisions with Nparticles hopefully we will see something soon
__________________
Showreel
RnD
 
  10 October 2013
Mandrak you are indeed a very helpful and nice nature person I have to admit here that you always listen and reply , no matter how long the thread extends in returns of urs help.I also have to respect the patience you have for learners.


Duncan also he is the god on this planet of Maya.

Sir Duncan God gives u more strength and passion to create the impossible and to beat the Houdini.
 
  10 October 2013
I've attached a simple scene that roughly matches that reference one( there is a old style particle tutorial mention for that scene, by the way, but it seems a bit more complicated than using nParticles ).

I think the main things are getting the scale of the instances about right with respect to the particle radius values, and controlling friction with the surface, bounce, particle size range, drag, emission speed values, etc. The rotation block has parameters that control how much particles slide vs rotate when they collide, as well as how much the rotation slows down when in free fall.

If you are going to have very large irregular chunks then those chunks might be better done with rigids.. or perhaps nCloth, which will better collide with nParticles. But keep the smaller bits using the instance technique.

That expression was just to intialize the rotations. In an explosion like this the particle tend to self collide at the start frame which gives them randomized rotations and rotational velocities. However with that expression you could really make them spin fast (or not spin at all) if you wanted. The angularVelocity is the rotational velocity. If you wanted the particle to stop rotating on collision totally you could do stuff like making the angular velocity zero.
Attached Files
File Type: zip particleInstancerExplode.zip (3.4 KB, 25 views)
 
  10 October 2013
You might also check out this thread:
http://forums.cgsociety.org/showthr...ghlight=casings

The scene file shellCasings.ma is also available here:
http://area.autodesk.com/blogs/dunc...ld-presentation
 
  11 November 2013
Hi,
I am back with some more questions.
So now I have got a Geo Instance explosion kind of working I now want to create a nParticle trail from each piece of instanced Geo, Another way of explaining this is I want my particles to emit particles. And I was able to do this by selecting my particles and going emit from object. The problem I have now as you can see in the video; The particles continue to emit even after the source particle has landed. Can some one tell me how I can make these particle stop emitting after the source particle has settled.
 
  11 November 2013
Originally Posted by Duncan: Attached Files particleInstancerExplode.zip
That expression was just to intialize the rotations. In an explosion like this the particle tend to self collide at the start frame which gives them randomized rotations and rotational velocities. However with that expression you could really make them spin fast (or not spin at all) if you wanted. The angularVelocity is the rotational velocity. If you wanted the particle to stop rotating on collision totally you could do stuff like making the angular velocity zero.


This is awesome Duncan !! Thank you.
The thing that isn't awesome is I am not able to view the expressions, is it because you created this in 2014 and I have 2013 ?
 
  11 November 2013
Originally Posted by mettam: ...I am not able to view the expressions, is it because you created this in 2014 and I have 2013 ?


Oh... somehow I must have deleted that expression... its not in the scene( the self collision at the start emission will cause rotations, anyways).

At any rate here it is...(a creation expression):
float $s = 2.0;
angularVelocityPP = <<rand($s),rand($s),rand($s)>>;
 
  11 November 2013
Originally Posted by Duncan: Oh... somehow I must have deleted that expression... its not in the scene( the self collision at the start emission will cause rotations, anyways).

At any rate here it is...(a creation expression):
float $s = 2.0;
 angularVelocityPP = <<rand($s),rand($s),rand($s)>>;
 


I think you didn't write any expressions for this effect? It's all achieved by plugging in and tweaking existing nParticle attributes, correct ? I say that because I can't see any custom expressions.
 
  11 November 2013
That's right... no expressions needed. The expression is just to show how one can control the rotational speed. Particles automatically rotate on collision and self collision. The particles have rotational velocity at the start even without that expression because they are in self collision at the start frame. A limit with using the built in rotation feature is that collisions are spherical only and don't use the geometry of the instanced object.
 
  11 November 2013
Also you asked about stopping secondary particle emission when particles stop moving. Probably the best is to control the emission rate based on the speed of the particle so when they stop moving they stop emitting.

Select the secondary emitter and do nParticles:"Per-Point Emission Rates". This will create a per particle attribute with the emitter's name on the first particle system. You can then do a runtime expression to set emission from velocity:
float $rate = 2.0;
emitter2RatePP = mag( velocity ) * $rate;
 
  11 November 2013
Thanks Duncan for your previous responses, very help full indeed.

In the Instancer (Geometry Replacement) dropdown I have selected Scale/radiusPP I thought this would make the Geo scale match the diameter of the particle ?
See the attached image: Is there a way to make the size of the Instancer Geo match the particle size.
Attached Images
File Type: jpg Profile_Of_nParticles.JPG (63.8 KB, 9 views)
 
  11 November 2013
It should work to select the original instanced object and just scale it.
 
  11 November 2013
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
__________________
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 12:36 AM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.