Author Topic: Spot on! Light objects - my go at visible lights  (Read 2842 times)

Offline KlausK

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Spot on! Light objects - my go at visible lights
« on: December 08, 2017, 10:39:18 PM »
So...
since that theme comes up every now and then I had a go with the Spotlight and the Light Source objects in TG myself (again).
Main goal is to keep the render time as low as possible yet have a more or less decent visible light.
This 1920x1280px took about 17min with Micropoly Detail at 1, AA at 8, Atmo Quality samples at 32.
A little bit of Cloud Layer v2 involved (Quality for clouds at 1).
Cheers, Klaus

ps: xoio winterpeople and hummer-3 from DMI Free 3D Models site.
pps: btw, what an awesome lot of high quality work posted in the last few days/weeks by many of you guys. Great stuff! A pleasure to look at.  ::)
« Last Edit: December 08, 2017, 11:34:16 PM by KlausK »
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Offline luvsmuzik

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Re: Spot on! Light objects - my go at visible lights
« Reply #1 on: December 09, 2017, 12:31:29 AM »
Nice one! :)

Offline bobbystahr

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Re: Spot on! Light objects - my go at visible lights
« Reply #2 on: December 09, 2017, 04:07:55 AM »
I like the render time there, gonna take a run at your set up...great testing.
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Offline Dune

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Re: Spot on! Light objects - my go at visible lights
« Reply #3 on: December 09, 2017, 05:50:31 AM »
That's really good in terms of haze quality and render time, Klaus! Can you explain the blurry dots in the sky? They look like snow, and if so, it looks really good as snow. Procedural?
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Offline KlausK

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Re: Spot on! Light objects - my go at visible lights
« Reply #4 on: December 09, 2017, 12:06:24 PM »
Thanks everyone!

First off @ Dune: the "snowflakes" are merely a lucky accident  :-[
This is only a background picture projected through camera.
It is a free to use Deep Sky picture of a constellation called Little Dipper. Here is a link:
http://www.deepskycolors.com/archive/2011/05/12/little-Dipper.html
Why it turned out the way it did surely has to do with my incompetence putting it in the background over the atmosphere correctly.

Ok, here is a little illustrated "How to" about the visible beam of light...

Important notice to start with:

 - all single pictures in the 'contact sheet' are rendered at 1280x720px.
 - AA is always 8
 - Micropoly is always 1

So the stages are really comparable. There are some notes in the pictures as well.

When you start out with one spotlight and maybe one cloud layer you have to crank up the quality settings for them
to a degree which is simply not tolerable in terms of render time. Especially when you only want a rather quick result.
If you are going for a 'Masterpiece' then render time is less important, I guess.

So, I noticed that because of the jittering of the samples every frame looks slightly different.
The white dots move around and leave gaps. The graininess I want to get rid off.

The idea is to fill the spaces more and more. Not with higher sampling values but with more graininess.
Add more spotlights on top of each other with different settings the Aperture width, the Falloff power,
for the Inner and Outer Cone Angles, Max Distance, Strength - you name it.
I also separated the lights between surface and atmosphere. What they lit and where they cast shadows.

In the pictures I rendered no spotlight actually added to the initial render time!
I started out with 4m30s and 1 spot, and after adding the next 5 lights render time still was 4m30s!
Adding the Cloud Layer added 2 minutes render time in the examples. Which is ok, I think for the effect it has.
Btw, when using the Cloud Layer the render times vary greatly depending on the Camera position I found.

Since we cannot group or parent anything in TG (hint hint ::)) using this technique is mostly helpful with still images.
Because placing the spots is a tedious work. But the rather low render time it yields is worth the effort for me.

This is the result after a few hours of trial and error. I think, this technique can be enhanced more. Use more spots e.g.

Hope that is useful (and I mentioned everything ?_?).
Cheers, Klaus



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Offline SILENCER

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Re: Spot on! Light objects - my go at visible lights
« Reply #5 on: December 09, 2017, 03:33:54 PM »
Nice spearheading on the V Light research.
And yes, just what I was thinking...another argument for parenting/grouping.
And maybe even instancing of those parented hierarchies.
And Alembic deformation as well would be a huge win.

Looks great. Might have to take a stab at the close encounters Devil's Tower shot.

Offline bobbystahr

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Re: Spot on! Light objects - my go at visible lights
« Reply #6 on: December 09, 2017, 08:13:04 PM »
Well after a few hours(mostly render time)I've figured out one needs your system to produce renders in that time. mine on this AMD average 4x longer than yours and way more than I was getting for my purposes. You know, it'd be really nice if they fixed that shader as it shouldn't be beyond reach as I was getting that smoothness in pre 2000 Imagine3D renders with almost default settings. maybe your experiments will add to the knowledge base for spotlights and trigger an inspiration...I am an optimist.
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Offline Dune

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Re: Spot on! Light objects - my go at visible lights
« Reply #7 on: December 10, 2017, 07:02:23 AM »
Thanks for your explanation, Klaus. 
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Offline luvsmuzik

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Re: Spot on! Light objects - my go at visible lights
« Reply #8 on: December 10, 2017, 12:09:41 PM »
Very interesting...thanks! I was about to make a translucent luminous cone object and call it a day.

Offline N-drju

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Re: Spot on! Light objects - my go at visible lights
« Reply #9 on: December 11, 2017, 06:54:34 PM »
This is very impressive but I'm afraid I'm not following you. :-[ Do you think you could make a tutorial out of this?
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Offline Kadri

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Re: Spot on! Light objects - my go at visible lights
« Reply #10 on: December 11, 2017, 07:12:59 PM »

Looks good. The use of more then 1 spotlights is nice :)

Klaus have you tried to use render layers? In case you haven't this is a fast and easy method too.

Make a new group and put the spotlight in there.
Then make a render layer node and go to the "Lights" tab and choose your newly made group with the spotlight in it.
You can render your spotlight with surface lighting or atmo lighting separately if you like (the atmo is the most grainy looking part mostly).
Then render only the lighting with the render layer node attached to the render node.
Blur this noisy render the way you want in post.

After this de-attach the render layer and render the full scene only with the ground lighting of the spotlight or without the spotlight however you choose (only surface lighting and-or atmo lighting) before.

Now just comp those two renders together in a photo editor you use.

This is very useful for animation but even on a single image you can get much more control on the spotlight strength and colour for example without rerendering the scene.

Below are crude examples from the default scene , with an added spotlight that is blurred in post (the atmo lighting part) and the original full Terragen render. Another example is with the same spotlight part blurred and duplicated 5 times in post.
I added this basic scene below too.

There are much more possibilities probably within the render layers node.

« Last Edit: December 11, 2017, 07:31:24 PM by Kadri »

Offline bobbystahr

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Re: Spot on! Light objects - my go at visible lights
« Reply #11 on: December 11, 2017, 08:37:36 PM »
@ Kadri...very nice results...noted for future possible use
something borrowed,
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Ring out the Old.
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Offline KlausK

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Re: Spot on! Light objects - my go at visible lights
« Reply #12 on: December 11, 2017, 09:56:06 PM »
@N-drju: can you be a little bit more specific about what it is you cannot follow? (perhaps this is something for Twitch TV  ::))

@Kadri: I haven`t used Render Layers very often so far and not at all in the way you show. Gonna try that too. Thx for your example.
What I have done instead was rendering different frames of the project with all the same setting for that 1 or 2 spotlights
and combined those in post. This works as well because of the sample jittering in the different frames.
Here I was after a solution to not use post effect outside of Terragen.

On the other hand since Blackmagic Design gives away Fusion for free I actually might be doing this sort of light effect
completely outside of Terragen - if it was a bigger scene with lots of different light cones. And I would surely try to get it done
in post when it comes to animation in Terragen.
Cheers, Klaus
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Offline N-drju

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Re: Spot on! Light objects - my go at visible lights
« Reply #13 on: December 12, 2017, 06:27:21 PM »
Well, well... I tried to reproduce your "stack of lights" solution for creating "god rays" and it was successful too! It works the same way - the more suns you have in a scene, the smoother the rays and shadows will be. Here are my attempts:

77718-0

So it indeed looks great. You just need to remember that you have to divide the sunlight power between all sun objects or you'll end up with ever brightening light source (that's why the third image turned out a bit overexposed ;)).

Unfortunately, each added sunlight also adds render time. I don't know why. :-[ In your examples you said that all renders took exactly the same amount of time to complete. I couldn't accomplish it (yet). But maybe what works for the spotlights, does not necessarily have to work for the sunlight(s)?

Anyway, sunlight divided by four gives quite a decent effect and it's well worth the time if you ask me. Your idea is a good solution for the god ray sharpness as well, which also tends to be one of the most problematic features that we struggle against.
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Offline luvsmuzik

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Re: Spot on! Light objects - my go at visible lights
« Reply #14 on: December 12, 2017, 07:24:03 PM »
Now there is an idea! What did that do to your bluesky color? This will be something fun to try! Thanks for sharing N-drju!