Rendering combo plant/tree and glowing effects scenes?

arcady

Putting together a scene that involves magic in a wooded area.

In so doing, with glowing effects and trees - it seems logical that I ought to use indirect light so that glowing objects will give off light. But with hundreds of replicated trees, and figures with subsurface shading... indirect light looks like it could cause an hour long render to become a week long render...

Any suggestions on the best way to handle that?

On mixing glowing objects with outdoor scenes involving complex transparencies like plants and subsurface shading?

Dartanbeck

Yes. Forget indirect lighting for that - especially for animations.
Instead, use a suitable light and have it ignore the entire replicator that distributes the trees, and parent it to the tree (drag the light onto the tree in the instances tray) so that in gets replicated along with the tree. Do this for each tree to be replicated. For trees that are not replicated, just make their lights ignore the tree that they are attached to - or whatever the glowing object is.

This way, the lights can still cast shadows without being blocked by the glowing object. Otherwise, if you don't need the illumination to cast shadows, you don't even need to have them ignore the object... but might look strange with no shadows - but it depends upon the overall effect you want.

I'm not a fan of using indirect lighting to get glows to illuminate. I find that I have a lot more control by using light linking, which is what the example above is: the lights are linked to everything except the object that they are attached to.

I also avoid soft shadows whenever I can, which dramatically decreases my time to render each frame. If it just looks too stark for what I want, I try lowering the shadow intensity a bit. Just going down to 90 or 80 (or any increments in between) can make a huge difference.

As an experiment on this, try disabling soft shadows on all of your lights and do a render. You'll be truly amazed at the render time difference. This has been a major study for me, but not as a written recipe, just stuck in my own mind for setting up my own scenes for animations. Another method I use to avoid using soft shadows is to simply add more lights. More lights adds more time to the render, so it takes a lot of thought regarding where the light really needs to come from to help diminish the harshness of the current shadows. But I find that adding more lights can still be amazingly fast at render time. So I tend to make scenes and light them up, set up a few cameras and save the scene so that they're ready for me when I need to film them into an animation.

arcady

Well the situation I have is a magical encounter in a daytime clearing - with trees around it and in the background, and small plants in the foreground.

The magical effects in the scene are multicolored and light the figures casting them (a color texturemap as the glow channel) - which was the reason I assumed I would be stuck using indirect lighting.
- These are presently done with Carrara fire and the HeroFX Alchemy prop.

You would suggest I link a light to the magical effects? Or rather link them every item in the scene other than the magical effect?
How can I link the lights to all the effects? Not parenting I presume? But that thing to tell it to light everything except X?

Oh wait, I see you're suggesting having the light be replicated.

Dartanbeck

I don't have Carrara on this little netbook, but if my memory serves:
Select the light in the right panel (under the word "Scene")
With the light selected, look in that right panel, but up higher, almost at the top.
There are two radio buttons, one is for linking to only what is selected in the box below, and the other is to link the light to everything except what is selected in the box below.

Since the magical effect has glow on it, it's lighting can be adjusted by that control in the shader. Note that you can even multiply the current glow setting with a value of 1-1000 for a lot more glow if needed.

So I put a bulb light in the center of the effect object at the beginning of the timeline (frame 0) and then parent the light onto the object so that it follows it wherever it might go.

While on frame 0, I set the radio button "Everything Except" and choose the object that I've just parented it to. Even if the object is mostly transparent, I still avoid having the light affect it, as light through transparency can also be a time consuming calculation on the render engine.

At 5:40 of this video you can see this in a basic example, where there is a bulb light parented to the lightsaber about a foot down the blade from the handle, even when the blade is retracted all the way in. At the appropriate time along the timeline, I turn the bulb light on by making it 'visible' in the right panel. I don't really need the lightsaber illuminated, but if I wanted it to be, I'd duplicate the light and set the new light's radio button to the other option,leaving the lightsaber selected, and then shift the light slightly, so that it's not intersected by the blade when it comes out. I think I used this two light setup for this scene.

evilproducer

arcady said:

Well the situation I have is a magical encounter in a daytime clearing - with trees around it and in the background, and small plants in the foreground.

The magical effects in the scene are multicolored and light the figures casting them (a color texturemap as the glow channel) - which was the reason I assumed I would be stuck using indirect lighting.
- These are presently done with Carrara fire and the HeroFX Alchemy prop.

You would suggest I link a light to the magical effects? Or rather link them every item in the scene other than the magical effect?
How can I link the lights to all the effects? Not parenting I presume? But that thing to tell it to light everything except X?

Oh wait, I see you're suggesting having the light be replicated.

To add to what Dart has said, if you need multiple colors in the light that is cast by the effect, you could use a gel in the light.You could also use an Anything Glows light for the prop object and set the AG light to emit from the glowing area. It will be slower than a standard light and gel. but faster than GI.

Jonstark

You could also render in passes, one with GI and the glowing object radiating light onto whatever it needs to hit, and then one regular render without GI and combine in post.

I think for most glowing objects putting a bulb light inside the object of the same color that is set to light everything except the glowing object itself (so the light can get out and won't cause the glowing object to throw shadows) would work.

evilproducer

Jonstark said:

You could also render in passes, one with GI and the glowing object radiating light onto whatever it needs to hit, and then one regular render without GI and combine in post.

I think for most glowing objects putting a bulb light inside the object of the same color that is set to light everything except the glowing object itself (so the light can get out and won't cause the glowing object to throw shadows) would work.

That is my preferred method as well. If the fire is casting light, I'll stick a bulb in the flame and exclude the fire. For added "heat" I'll use a 3D light sphere set to realistic on the bulb that is in the fire. It really helps to add a hot look.

Click the example images for a better look than the forum preview gives.

Dartanbeck

That's really neat, ep!