# Particle simulation experiments (Tornado, Texture field mini-tutorial page 2..)

This thread will contain a series of experiments I am conducting evaluating the particle system in Blender 2.46. The first test is attempting to simulate a tornado.

A rendering of the 3D viewport can be found here: http://www.vimeo.com/1354475
I recommend viewing it full screen to see the rotation of the particles.

If you’d like to test out the file. It can be downloaded here.

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That’s excellent! I’ve always tried to solve this by building a funnel rather than making a physical base from which to draw the funnel medium (dust or water). So is that a plane emiter with a path deform? Would be greta with a bit of animated wiggle in the funnel.
Good job, will you be attaching a cloud of cards for texture? I’ve foundy this to be problematic at the ground interface. Causing hard edges at the intersection.

At the moment I’m mostly attempting to replicate the motion and effect with the particle system. The next set of experiments will deal with the visuals.

I’d recommend just downloading the file and baking the simulation. But the particle system is using a curve force, vortex force and harmonic force. The curve force has additional motion with the use of a braid effect.

This test is an attempt to replicate the following simulation done in XSI:ICE: http://www.vimeo.com/1313863

It is the motion along a curve. Which you’d think would be easy. But curves do not have a force along the length of the curve, but instead pull/push from the starting point. The solution was a series of curve forces tied together.

Find the Blender version here: http://www.vimeo.com/1355859

Wao.Can you replicate that also ?( http://www.youtube.com/watch?v=SAOuRilsYtM)

wow, good results indeed!

In my ongoing endeavor to understand the particle system tools, I’ve started to put together a color coded diagram to illustrate how colors effect the direction of a texture force. With this I’m hoping to gain some control over the results of a painted texture force. I’ve attached the beginnings of this diagram. Its just a preliminary diagram, so its not complete. The blocks of color indicate how the particle direction would be effected in a planar sense if the entire force were that specific color. This in no way takes into account dimensions. SO some of the colors cause the particles to go positive on the Z and some to go negative in the Z.

I’ll continue to work on this and my next experiments will involve utilizing a texture force with this control. (hopefully effectively)

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To touch on the curve field used in the Tornado example I’d like to direct attention to a Blenderstorm request I’ve submitted: http://www.blenderstorm.org/qapoll/ideas/idea/566/

I think adding the few features outlined in my proposal could greatly improve the usage and capabilities of the curve field. I’ll outline them again here and hope we can all discuss the rationale.

1. A strength slider to increase and decrease the field effect on the particle system’s motion.
No method currently exists to adjust the strength of the pull/push of the curve field. Its difficult to adjust timing with the current system. And a strength control would unify its method of functionality in tune with the other existing fields. All other fields have a strength setting why not the curve field?
1. A curve force along the whole length of the curve and not just from the starting point. Another way to describe it is that particles would be pulled along the whole length of the curve not just from the starting point. A good solution is that each point on the curve acts as a pulling/pushing force. This should be an option and able to be turned on/off.
Current usage of the curve field is limited to essentially a path for particles to follow. This could be expanded upon if each point could act with the same push/pull effect and drawing particles in along the entire length of the curve. That way simulating more controllable fluids, smoke, sand, etc. would be a lot easier to accomplish.
1. Tapering of the particles along the path. This could be adjustable via the curve handles.
No method currently exists to control the shape of the particles traveling along the path. In the example of the tornado it would have been beneficial to have the particles deform in shape while following along the path.
1. Option to slow particle motion around bends. With a strength slider to control the dampening.
When attempting to simulate an effect generally you are trying to simulate it in a physically accurate way. With that in mind things like fluid, lava, etc have different motion when flowing around curves. The current curve force lacks the ability to simulate this effect.

Not at the moment. I’m working on texture fields and figuring them out. But once I get through with that I’ll take a look. I do believe that a similar explosion example is available in the wiki.

That’s impressive work Brian! Now I know who to bother about particle questions. :yes:

So Brian…did you see the new cgsociety FX challenge?!

I’d love to see what Blender can do as far as the challenge topic goes. You up for it?

Saw it. Thinking about it. Not the greatest with materials and transparency. The system is quirky regarding that. But I might give it a try.

It says video no longer availabe I wanna see it…

I think its an issue with Vimeo. If it isn’t resolved soon. I’ll just upload them somewhere. For now please feel free to download the source file and give it a test.

May I insert a brainstorm?
Layer one would be the bulk of the body done with the cloth sim. What I am thinking of is a tornado shaped cloth rotating at high speeds. Maybe you should tweak the local stiffness of the cloth to maintain that characteristic twister shape.
The next layer should be something like a thin cloud texture attached to the tornado (like in the realistic clouds in Max thread).
The last layer should be flying debris flying chaotically around the tornado. I think that this could be best done with boids because although the debris might be rotating around the twister, from a distance it looks like a swarm of mosquito’s.
Finally at the mound of the tornado, setup a emitter that spewing up fine dust.

About the cloth idea, maybe the twister should be rigged so that it won’t collapse on itself, Maybe some internal stiff edges?

The added advantage with this system is that you can make the twister make that ‘curvy dance’ using wind force fields.

Interesting idea. Though I think you might make things more complicated using cloth. And of course my point is to test the particle system

Not to be a negative Nancy, but I highly doubt that you’ll be able to compete with what the CGtalkers will be able to produce using blender. The material system is just too limited.

Hope someone takes it upon themselves to prove me wrong – and actually succeeds. But we’ll see.

I’m open for debate. What is wrong with Blender’s material system? Or lacking rather.