but I don’t know how I would do this using particle systems. I’ve really never worked with particle systems. I need the “edges” (according to camera angle) to glow brighter than the rest, like in the video, and I’m looking for the same kind of “shimmer”. If someone could give me a starting point, that would be swell. I need specifics about the visualization parameters etc.
I’m resurrecting this thread. I appreciate the reply Atom, but that wasn’t quite what I was looking for. Both of those threads are about post-processing methods, not particle systems. The corona in the video I linked is obviously a particle system. It’s also animated in such a way that the flares gradually shrink/grow/shift around. That’s what I’m trying to achieve. I just have no idea what settings would give me something like this. There seems to be a shortage of tutorials on particle systems, and the ones that do exist are very basic and not applicable to what I’m trying to do. The particle systems section of the manual mainly focuses on a few particular applications of particle systems (smoke, fire, hair, etc.) I can’t even figure out how to turn the force of gravity off. Besides particle system settings, I need to have an idea of the material settings that will give me the effect I’m looking for. Can anyone point me in the right direction? Help greatly appreciated.
This can be done with texture as well you know. Here is my quickie:
It is made of two spheres; one with sun surface texture and the other slightly smaller sphere with Halo material. The sun surface texture is simple two layer of Stucci; one scaled down for surface feature, mixed with one scaled up for uneven area effect. They both can be animated to shimmer. Halo material glow gives the edge effect.
To try and match what is shown in the video with particles, I think I’d use a subdivided icosphere with vertices drawn out into points, with the points rising and falling via shape key animation. This would be used as particle emitter, with the initial velocity (probably all in the Normal vector) very low so the particles basically stay very near the emitter surface. Random lifetime, size, etc would help provide for variation in apparent corona density, etc. Two interacting systems might be interesting, also.
I’d likely use a halo-type particle, but material specs would be subject to a lot of experimentation in terms of halo size, hardness, transparency, texture(s), etc. It’d be hard to predict how any particular set of specs might look when rendered.
This is a sun I created about a year ago, based on different NASA photos. I had a rough solar flare animation working with particles, but it looked a little too ‘blobby’ with halo settings. If you want more of the streak effects, I might recommend using the “Trail” option in the particle render settings, and set it higher than 10.
to add to the previous question, if the icosphere is being deformed as such, not all the normals will be pointing directly outward from the center of the sphere, so the particles will emit in more or less random directions, which isn’t what I want. Is there a way to work around this?
Here’s another problem. Using halos as the particle type, if I set their size to really small, they look like thin, discreet solid lines coming out of the sun. But the more I increase the size, the more the halos overwhelm the textured sphere until you can’t see it at all. This is what I expected would be the case. What I don’t understand is how the author of the video got the particles so dense and bright around the corona while not interfering too much with the sun texture.
Not truly randomly, but yes, as that seems to be the kind of motion shown in the video, plus it mimics to a degree the pulsations in a stellar corona. By setting up a number of shape key sequences and then keyframing them with different periods and out of phase with one another, you can get a pseudo-random look.
Halo materials can be less than intuitive to create, I often spend a fair amount of time getting them to look OK. Also consider the unit size of your star model. If it’s too small in Blender units, you may need to reduce the Halo size too drastically for good effect. To get the coronal/halo material to let the underlying solar surface to show through, try using a low alpha and enable the Add mode for the halo.
I’m kind of embarrassed to show this, but this is what I’ve been able to come up with so far:
That’s with the particles set to low alpha and add. In the video as well as ridix’s picture, the edge circumference of the sun isn’t clearly discernible like it is in my picture. Maybe this is just because the colors of the halos and the texture don’t match? But I don’t want them to. I want the sun to be a darker red and the corona a brighter orange. Even if I change the halo color to match the texture, you see that it really obstructs the sun texture even with the settings you (chipmasque) mentioned. I’m just not getting this.
The pattern on the Sun changes, but neither flare nor prominence are present. It looks, to my eye, fairly realistic without a coronal mass ejection. Although the Sun’s colours, viewed from space, should be much more on the white side. If you have questions, let me know.
If you’re trying to model the corona, then I think you’re staying much too close to the surface. The corona starts just above the photosphere and extends far out into space, a full solar diameter or so for Sol. If you’re trying to model the photosphere (the sun’s visible surface), the edge (limb) should be fairly crisp, it has no atmospheric “haze” the way a planet like Earth does.
Be that as it may, to “fuzz up” the sun’s limb I’d either use halo particles (again) that sit on the surface, or nested spheres with various transparency and Fresnel effects, much like what have been shown already. An alternative to halo particles but one which can stress your comp because it means millions of polys, is to use an object instead of halo particles. You can apply a material/shader that can present much different and more complex effects, you can make the shape irregular, you can randomize the size and rotation, and much more. But like I said, it means many hundreds of thousand of thousands of particles and each with its own geometry, even if it is a duplivert-type instance.
Okay, I guess what I’m trying to create isn’t technically the corona. But I’m not going for the most physically accurate depiction here. I just like the look of the bright fuzz around the limb as seen in the video. Judging by how it looks in the video, I would need halos with very small bright centers (to form the faint “lines” extending from the surface) and much larger and fainter “fade out” regions to give the following effects: 1. the halos don’t interfere much with the visible surface texture, but interfere more with it the closer to the limb they get as a result of their combined effect as their distribution becomes more perpendicular with the viewing angle, ending with a very bright fuzz around the limb; 2. the shapes of the individual halos is not apparent (much on the contrary to the picture I posted); 3. The fuzz around the limb blends to some extent with the limb, making the limb not-so-sharp.
The video was made in blender, so this must be possible. But I’ve tried messing with the (rather limited, imo) halo settings, and I cannot get such halos. The halo “hardness” setting has no effect whatsoever beyond the default value of 50. As I’ve said, I’ve tried setting the halos to low alpha with the “add” set to 1, and got the effect in the picture I posted. “extreme alpha” has no noticeable effect.