Textures to deform particle paths

Hiyas. I was wondering how this is done exactly. I know you have to put a texture in channel 8, but what kind of texture? And how is do you get the particles to follow it exactly?

My assumption is that you can use an alpha texture like for hair or something, and that the particles would come out looking like hair :slight_smile:

An example of of a mesh with particles using a texture to deform the particle path is shown here, but it doesn’t even hint on how it’s done.

Any help would be much appreciated, this is fun stuff to play with.

Ya I’ve been wanting to know how to do this as well. I think @ndy used it for his snowman.

the texture is use to indicate the direction of the the particle. When oyu got you texture in channel, 8. then play with the option. all in the down-right corner of the panel. You have to set the tex: option to somethin > 0.

K, that doesn’t help, but thanks. I’m figuring it out as I go now though.

The texture you put in acts the same way bump mapping does. The lighter part of the texture will cause particles to speed up, so to speak. What I did was make a black texture with a white spot in the middle of it. I made a heavily subdivided plane and added that texture to the 8th channel. Then turned particles on and upped the Tex that says ‘Let the texture give the particle a starting speed’ a bit.

This caused the particles that were over the white spot in my texture to go up when the Z factor in the Teture xyz was upped.

One of my problems is that I can’t get the white spot to send out particles away from the normal. Like if I have my white spot repeated on a sphere, the particles won’t go outwards, they’ll only go straight up from the white spots, or along x,y pending on what those are set at. If I up the Norm, then the white spot is ignored and particles go out from the mesh like usual.

I think you could also use the RGB values of the textures as opposed to just intensity (black/white).

right. the rgb and grad is more what you want. also the nabla is usefull. din’t know why. but it does help to get some.

Using this texture spherically mapped on the sphere:

I get this using Grad:

and this using RGB:

The only other setting I change in the particles window is setting the Texture Z value to zero, and incresing the Tex value. Why can’t it just go outwards where the white squares on the texture are?

How the texture affect the particles is not related to the direction of the normals, it’s mapped to global space.


k, thanks Theeth, (spelled it right!). Guess I’d have to map a texture to the faces seprarately around the sphere.

Uhm… I guess I wasn’t clear enough. The only way to make particles move in the direction of the normal is to increase the Nor setting. The Tex setting is not dependant on the orientation of the normal, it will act the same whatever the rotation of the faces is.


Ummm, no you were perfectly clear. What I’m saying is that the only way to get the Texture speeded particles to go outwards from the sphere is to have emitters set around the sphere and their xyz texture forces set to force the particles away.

Like this:

Of course I’m slowly realizing that this is pretty stupid way to go about things. :slight_smile:

That would be equivalent to using a Nor force anyway. Using a Tex force is mainly useful if you want to add a little twisting to each particles. Something Rand isn’t good enough to do.


ya, but Nor force away is based on the face, not the texture right? Sorry for being simple here… What I reallly wanna do is make that thing they made on the page I linked above. They said it uses texture to deform the path, but I don’t see how they did that on a sphere. The texture causes the particles to speed only along the global, and if I use normal force it forces the face particles normally as if there wasn’t a texture.

Oh, I see. I skimmed through the first post quite fast so I didn’t quite get what you wanted to do.
It’s not that hard actually. Like I said, it’s basicly a Nor force with the 8th texture channel used to twist the particles around (Using the Grad mode).

Here’s an example I did when trying to replicate the effect: http://www.clubinfo.bdeb.qc.ca/~theeth/Temp/Particles_Texture.blend

Hope that’s helpful.


not that much. But this show a good use of the stretch-to constraint. :wink:

Think you got the wrong blend, that one has just an armature in it.

Thanks for your time on this!

Argh. That’s what I get for saving as untitled and renaming later. I picked the wrong file. Should be ok now (same link).

Gabio: IIRC, that was the start of a demo file for flexible joints using stretch-to. Maybe I’ll finish it someday if enough people ask for it.


This is too cool to play with. Thanks again Theeth.