Luminous, glowing spheres anyone?

[The Dome]

This is my first post ever to this forum, so hello all Terragen fans and professionals! I can see already that there are tons of knowledge to dig through here. Good that Christmas is coming - there'll be much time to experiment with all that.

Okay, but for starters I'd like to ask you whether any of you had ever tried to create colorful, glowing spheres, that cast multicolored lights? I've been trying to create something like that but ended up with this...

[attach=1]

As you can see, the colors on the surface are quite bright but the problem here is that the ground beneath the sphere is completely dark. I used default shader that is each sphere's surface by default. Then, I added color image and luminosity image (both the same image files.) Maybe I was a tad naive, but I expected that each color on the surface will emit likewise colored light on the ground. Well... it didn't.

Could you please share some tips on what could I do to make this happen? I tried to add a light source inside the sphere but that doesn't help either (the light is always single-colored.) Thanks for help, have a great day!

[WAS]

I attempted this with planets and someone provides a nice example. It may be able to work in small scales and even provide some glow, though I'm not sure. I'll grab a link.

Here you go http://www.planetside.co.uk/forums/index.php/topic,19283.msg188796.html#msg188796

[Upon Infinity]

You can try increasing the luminosity, increasing the GI strength on surfaces, and increasing GI detail.


Here's a similar thing I did awhile back.

http://www.planetside.co.uk/forums/index.php/topic,15004.msg146188.html#msg146188

[The Dome]

Hm, but you see Upon Infinity - this sphere of mine already has luminosity value of 2! Yet, I get no glow on neighboring surfaces. The GI won't help much in this case.

Your example is practically the same of what I would like to avoid. The light that this panel casts is mostly white, while the picture on the panel itself is partially blue, partially yellow etc. Logically, there should be glows on the ground that reflect those colors.

In other words, each color should be emitting likewise colored glow. I think so...

I'll take a look at Dune's work later on, but from what I see it's basically the same, meaning that there is one surface color, so you can easily do lights in this situation by just adding light source.

[bobbystahr]

You need a much higher number for Luminosity to cast a glow I think.

[Upon Infinity]

Hm, but you see Upon Infinity - this sphere of mine already has luminosity value of 2! Yet, I get no glow on neighboring surfaces. The GI won't help much in this case.

Your example is practically the same of what I would like to avoid. The light that this panel casts is mostly white, while the picture on the panel itself is partially blue, partially yellow etc. Logically, there should be glows on the ground that reflect those colors.

In other words, each color should be emitting likewise colored glow. I think so...

I'll take a look at Dune's work later on, but from what I see it's basically the same, meaning that there is one surface color, so you can easily do lights in this situation by just adding light source.

You should take my word for it.     For I have done the very same tests and spent hours attempting to get what I want from them that you are performing now. 

There's more on what I did here:

http://www.planetside.co.uk/forums/index.php/topic,17433.msg168964.html#msg168964

Also, what you are attempting is the very definition of GI.  Making it a bit brighter would help.  But more than that, your Strength on Surfaces will make the difference, as well as upping your GI detail.  One is in the Enviro light shader.  The other is buried in the GI sample quality of your Render shader.

Keep in mind, however, that Terragen does not employ 'brute force GI', and may not perform as well as you hope for in this case.  But I assure you, you can get it to glow at least somewhat.

[bobbystahr]

Also went ti UI's link and there is a .zip of a project I did based on UI's first post there that is quite successful.

EDIT

messed up and posted this at the original thread so here it is in context.

I re visited the hexproject I have up at the other thread with the updated program and am much pleased with the result. Bounce to the ounce is largely responsible but I put a spotlight 20 m. down under the ground and I haven't done a control but think that's also contributing but there is no  actual light other than the spotlight.

[The Dome]

Hey, thanks for the feedback. I've been away for a while.

I managed to light things up, by rendering with higher GI settings/luminosity/light sources/otherthingsicantname and I can achieve glow effect with different objects, so... I guess it's fine. I've seen your project bobbystahr. Good work.

Still, I don't know why but the in-built TG sphere object does not seem to cast any glows, regardless of settings. Oh well, I don't care really. Others work just as I want!

EDIT:

You mean this is a TG3 render bobbystahr? The spotlight thing?

[Oshyan]

Spheres should work as light sources. See attached.

Just remember Luminosity strength is *relative to area*. As you increase the radius of a sphere, every doubling in radius is a quadrupling in area. So if you make the sphere 2 meters instead of the default of 1, you have to multiply luminosity by 4 to get the same brightness-per-area (i.e. to maintain the same appearance of surface brightness and the same illumination of the surroundings). Think of it like this: Luminosity is a value of light that is emitted from the surface of the object at the value specified, and the value is essentially distributed equally across the whole surface. If you increase the size of that surface but do not increase the Luminosity value, then there is less luminosity per area, and the surface appears dimmer since the same value of light is spread out over a larger area.

- Oshyan

[bobbystahr]

Spheres should work as light sources. See attached.

Just remember Luminosity strength is *relative to area*. As you increase the radius of a sphere, every doubling in radius is a quadrupling in area. So if you make the sphere 2 meters instead of the default of 1, you have to multiply luminosity by 4 to get the same brightness-per-area (i.e. to maintain the same appearance of surface brightness and the same illumination of the surroundings). Think of it like this: Luminosity is a value of light that is emitted from the surface of the object at the value specified, and the value is essentially distributed equally across the whole surface. If you increase the size of that surface but do not increase the Luminosity value, then there is less luminosity per area, and the surface appears dimmer since the same value of light is spread out over a larger area.

- Oshyan

Now that sure explains it well...been thinking of how to phrase that for hours....well done Oshyan

[Matt]

Spheres should work as light sources. See attached.

Just remember Luminosity strength is *relative to area*. As you increase the radius of a sphere, every doubling in radius is a quadrupling in area. So if you make the sphere 2 meters instead of the default of 1, you have to multiply luminosity by 4 to get the same brightness-per-area (i.e. to maintain the same appearance of surface brightness and the same illumination of the surroundings). Think of it like this: Luminosity is a value of light that is emitted from the surface of the object at the value specified, and the value is essentially distributed equally across the whole surface. If you increase the size of that surface but do not increase the Luminosity value, then there is less luminosity per area, and the surface appears dimmer since the same value of light is spread out over a larger area.

- Oshyan

That only applies to light sources, so that total energy is independent of the radius of the light source, so that light sources behave like traditional CG lights. But surface shaders don't work that way. With a surface shader, the luminosity is literally the colour of the surface, so making the object bigger will increase the total energy it emits.

Matt

[Oshyan]

Huh, seems like really high values are still needed on large objects though, no? I mean I guess I was mistaken about this, and thinking about light sources as you say, but then does that mean it's just a GI limitation, or something isn't working right, or what?

- Oshyan

[Oshyan]

Ok, I just re-tested and it's working correctly. I must have just gotten confused with light sources, which makes sense but is annoying. Sorry if I confused anyone else. Lots of info to keep in the ol' brain here.

- Oshyan