Creating visible magnetic fields.

Hi,

I’m looking for advice on creating visible magnetic fields. I don’t need to create the physical effect just yet. I’m thinking I can create a transluscent shape to show the area covered by the magnetic field but I also want to show the lines of flux and direction from pole to pole. Something similar to the way paths show normals in blender would be great to show lines and direction. (If only they would render :D).
Any ideas to point me in the right direction?

Thanks in advance.

Maybe you can create a sphere. Subdivided a bunch of times and create a thickness… (either by duplicating the original sphere or using the new modifier in 2.5).

Then you could separate the spheres using the P command and have a bunch of separated round shapes (vertical or horizontal depending on what you’re looking for).

Then you could modify them (making the end points thinner and smaller, deleting a portion of the loop, etc) Finally you could apply a semi-transparent material using the color ramp and maybe a cloud texture to make somewhat ghostly lol…

You will have to use some post-editing to make it look better.

P.S. You could also just model one of the “magnetic fields” and use a polar array modifier…

Thanks Jota.

For my first project I only need a straight magnetic field (2 parallel poles facing eachother) but later ones will definately require circular fields so I’ll keep your suggestions on the spheres in mind.

I haven’t dabled with array modifier yet so that will be my next task.

Yes a ghostly haze that hints at the area covered by the magnetic field, translucent enough to allow the lines of flux to be clearly seen.

Thanks again.

there is a magnetic field in force panel!

i thnk there is a way to make this in the particule system with a field type magentic
but have no experience with this one yet

so may be somone with more knowledge in particules can help here

salutations

I think that “magnetic field” is a force field… is not really a visible object or mesh… not even a particle… (that’s just me guessing)… force fields are used along with particles to create a certain effect, e.g. using a “wind” force field and smoke will make the smoke particles move like there’s was a wind current.

I think lynchy is looking for a visual approach to the magnetic field (more like an infographic) rather than a simulation using a particle system… maybe you can clarify this lynchy?? and btw… if you have a sketch or a picture that can illustrate what you need ( straight magnetic field (2 parallel poles facing eachother)) … that way i can point out some ideas regarding the modelling… and also the way you want the flux to be seen… cause for that you could use a mesh or even a particle system most definitely along with the compositor…

only an idea here
i did use the wind and vortex one but no this magnetic one!

particules should follow the force field
so if you select magnetic i think it should take the shape of magnetic lines like a magnet i think
but i have to admit i never really use that one

salutations

Thanks Ricky,

I have seen that in the physics tab but at the moment I only need a visual representation of something that is invisible in the real world rather than to simulate actual magnetism. The possibilities for that are immense though for creating interactive resources for my students using physics and the game engine.
I’ve learnt in the last few days since starting a project of my own rather than doing video tuts from the net that i’ve got a lot to learn and a long way to go.

I’m enjoying every second of it though. I’ve been messing about with the lines of flux using very slightly beveled curves (straight ones :eek:) so they render. I started with a light green but they looked too much like lasers a darkish blue seems to work ok.
For the “spooky” field area I’m using a cube with a material using Z Transparency Alpha of 0.03 and a shader emit of 1.1 and a colour cloud texture (thanks Jota) using Veronoi F1. I have no idea why this works but it just does.
The only issue is that the light is reflecting off the cube too much, sort of pronouncing the cube shape too much. I know there must be a way to turn that off I just haven’t found it yet.

I wasn’t knocking video tuts earlier though, I am truely grateful to all those people who create them. Sometimes though you just gottta dive in and get your hands dirty. :evilgrin:

Well… using z-transparency has its limitations… ray transparency allows for a lot more control over the transparency settings (it takes more to render but if it’s one one frame it should not take a lot so you may wanna try that)

The problem with the light revealing the cube’s shape could be probably corrected using the proper lighting… what types of lights are you using… using lights and transparencies can be tricky so be careful… take a look at this tutorial, it’s very simple: http://www.blendercookie.com/2009/07/07/learning-3pt-lighting/ it’s not a solution for all situations but it’s a very good starting point; hope it helps…

Jota,
I need to get some web space to put some screen grabs up, As soon as I have it I’ll put some up.

The animation is to be a very simple DC Generator with a single loop and a split commutator.

Here’s an example from you tube.

That one is too cartoony for me. I’d like them to look realistic and be able to zoom in on the carbon brushes to see the spring and carbon brush touching the commutator etc etc.

Theres no time issues involved as I’m doing it in my own time mostly.

Cheers

I have seen that video, blender cookie has some amazing vids.
I’m definately no artist and probably aproaching this project from all the wrong directions but i’m thoroughly enjoying it. At the minute the only light is the default spot, I’m still getting the modeling together at the moment and will tackle the finer points as I go.

Its 1.15am here in London so I’m off to bed. How do I tell my girlfriend I’m busy this weekend. :evilgrin:

The only way to avoid the cartoon-ish look is to apply materials and textures effectively, use a correct background and lighting and use the compositor or some other post-production application to modify the look of it all.

First you should model all of the parts (all those components you mentioned above) and then you should get down to the animating part… but before animating you should create a correct environment (lights+background), otherwise when you move the camera you’ll mess it up.

It’s 20.12h here in Costa Rica… i guess there’s about 6 hours of difference? between us… don’t worry… you’ll read this tomorrow lol… :evilgrin:

Got some feedback on my progress so far from some colleauges. Everyone said that the hazy magnetic field just confused the clarity of the model. I asked some students to have a look and they said that the lines of flux was enough to show the area covered by the amagnetic field so I’ll ditch that for now and maybe have another go when I’ve got some more experience with lighting and cloud textures.

I’ve got myself into a bit of a pickle today. Did a lot more work on the modeling but somehow I seem to have locked rotation. None of the locks are enabled in the transform panel but I seem to have some animation/actions appeared in the outliner panel. I was messing with some rotaion in the timeline. I dont have any keyframes showing but I dont seem to be able to delete the animation/actions from the outliner panel. I’m not even sure this is the cause of the locked rotation.

Any ideas as to places other than in the tranform panel where one might accidently lock rotaion of objects?

mmm… that’s weird… in object mode, try alt-z (i think)… it resets the object’s rotation to its original position… make sure you’re in frame 1… (if it’s not alt is with shift…)

Its realy weird there is no rotation set, all the values are zero.
If I change the values in the transform panel (Keyboard “n”) then the rotation works but if I hit “r” to rotate a selected object, the dotted line and arrows appear but the rotaion has no effect. Even the rotaion gimbal has no effect if I turn this on and try to drag any axis. I’ve just noticed that exactly the same is happening with scale, although “g” works fine for moving any object?

I think its definately something to do with animation.
I remembered that opening a 2.5 blend file in 2.49 brings up a warning that some data will be lost including animation.
So I did that, opened it up in 2.49, saved with a different name then reopened with 2.5 and everything was fine. All the animation stuff in the outliner had disappeared and I can rotate and scale using “r” and “s” keyboard shortcuts.

I’ve still got the suspect blend file so I’ll try and see how to delete that anim data in 2,5.

maybe you changed the pivot type or added a constraint without knowing it!

then you probably added a keyframe… delete all keyframes!

Thank you Jota the rotation and scale was due to the “manipulate object centres only” button being activated. (oops) I guess that setting was also lost when I saved in 2.49.

Still cant seem to delete the animation/actions from the outliner though.
I cant see any keyframes in the timeline.