Rainbow

bigben · March 14, 2008, 08:36:21 PM

Here's the double rainbow so far. The primary doesn't have a minimum density set this time. I prefer the version with a minimum density as it's a more subtle. Render quality settings also make a difference. Increasing AA makes the rainbow a lot smoother and increases it's transparency... (larger cropped render in progress)

This image Detail 1, AA 2. Next test is Detail 0.5, AA 6 and is looking much nicer. Also tweaked some of the gradients to try and improve the colour distribution

Mr_Lamppost · April 06, 2008, 09:03:44 PM

I sort of let this one slip past while I was engaged on other things.

Amazing results. When are we going to see a completed scene? Is ther light at the end of the rainbow?

rcallicotte · April 07, 2008, 09:32:49 AM

This could be very useful. I would never have thought such a thing was even possible in TG2.

bigben · April 29, 2008, 05:52:19 PM

Hi All

My relative silence here has been due to life taking precedence over tinkering, but I have managed to squeeze some time back in. I may tinker a bit with the alpha on this one but I have a few things to sort out first. Had a play with clouds again and have what I think may be some suitable clouds to go above the rainbow.

I think the gap in this project has been useful in that I have to rethink what was going on, and some of the cloud/fractal settings are making more sense to me and I seem to have some control to change the clouds to what I want

I'll hopefully have something to show after the weekend.

Mohawk20 · April 29, 2008, 05:59:57 PM

I hope so, you're doing a great job!

bigben · April 30, 2008, 07:14:46 PM

I did a test render of on of the latest TGDs (http://forums.planetside.co.uk/index.php?topic=3517.msg37111#msg37111) in the alpha and the increase in render speed was amazing. This has been the first time that I've seen my rainbow rendered with detail 1, AA 6 and GI (not applied to rainbow nodes). The complexity of multiple cloud layers had really slowed things down but now it's actually practical to use higher quality settings. I'll benchmark it later when I have some time just to make sure it wasn't just my fading memory

.

bigben · May 05, 2008, 05:02:10 PM

[attachimg=#1]

Detail 1, AA 6, GI 1,2 (alpha).... and no, it doesn't go any bigger

Short of the odd nap while I had to do some work, the render time is somewhere around 20 hours... somewhat longer than the previous quick test.

This has a new cloud layer and I restricted the rain to the same depth as the rainbow (all restricted by two distance shaders). Needs to be darkened a bit.

Tweaking the intensity is somewhat difficult to predict at the moment, but this test probably shows the upper and lower limits. The primary rainbow needs to be darkened a little and the difference between the primary and secondary rainbow needs to be decreased a little (controlled by a single multiplication factor)

The only other thing to test will be the sharpness of the edges... and maybe checking the relationsip between cloud samples and the noise of the rainbow as it "fades". Time for some cropped larger render tests

Tangled-Universe · May 05, 2008, 05:27:39 PM

Amazing work Ben, admire your node-creativity and knowledge

It's a pity these complex setups take so long to render, but that's inherent.

Martin

bigben · May 05, 2008, 05:50:59 PM

In this case it's not entirely the fault of the complex network. It looks complex but it's mathematically quite simple. Applied to a surface it renders quite painlessly

. In this case, it's probably due more to the fact that there are 5 cloud layers that mix together to form the rain/rainbow, while having a large cloud with ray traced shadows visible through them. That makes for some pretty heavy calculations.

What was also interesting was watching the two squares rendering at the same time. In other renders each thread renders at about the same speed but in this one the split was 1:3, with one thread rendering the first and last square (out of

The top right square 1/8 took almost as long to render as the rest of the image.

Oshyan · May 06, 2008, 12:07:10 AM

Wow, a pity it takes so long to render, but the results are gorgeous! Once the memory issues are sorted out with multithreading I'd love to throw one of my quads at this if you're interested.

- Oshyan

bigben · May 06, 2008, 02:40:50 AM

I may take you up on that. I'll release the clips for the rainbow after I finish them and render something nice

rcallicotte · May 06, 2008, 09:13:02 AM

Pretty cool lookin', BB. Excellent work.

nikita · May 24, 2008, 11:40:55 AM

Quote from: bigben on March 10, 2008, 07:06:20 PM
If you could apply a colour function to a cloud it would simplify things a whole lot

I'm not sure if this has already been mentioned somewhere in the thread but: I think you can. Use it as your density shader.

j meyer · May 24, 2008, 01:08:54 PM

nikita - sounds interesting,could you please post an example?

nikita · May 24, 2008, 09:32:32 PM

I attached an example, a screenshot of it's network and a thumb of the texture used.
It's fairly simple... just multiply the color function, in this case the image map, and your density shader and that's it. Just make sure you're using multiply color (or multiply vector).

I haven't had the chance to do more testing yet, but as far as I know now, the brightness of the supplied color function (the length of the vector) is used as the density function. (This means you can't vary the brightness of the cloud using a function.)
The color set in the cloud's preferences affects the final outcome of the colors in the rendered image too. I guess they are multiplied as usual.

My test uses a single texture for the whole rainbow, projected onto a thin cloud sphere. It's far from perfect, but I think you could make a nice rainbow if you use all the other techniques described and/or used in bigben's project. Most important: reading colors from an image is basically the fastest method of "computation". And you don't need 3 cloud layers anymore. This could speed things up.