Altocumulus R&D

[Matt]

Inspired by a nice Vue image that was published recently. This was rendered in the upcoming Terragen 2.1, but a similar approximation is possible with 2.0. Render time 6 minutes 29 seconds on 8 threads, i7 920, 2.6Ghz.

Files now available here: http://forums.planetside.co.uk/index.php?topic=3691.msg85522#msg85522

Matt

[littlecannon]

Very nice Matt. 2.1 eh, I can't wait. Renders do come out nice with the new version don't they.
Cheers,
Simon.

[Seth]

nice altocumulus indeed.
and nice to see you rendering something Matt ! ^^

[Kadri]

Nice render Matt.
Are there any changes for rendering clouds you can share with us at this time Matt ?

Kadri.

[Zylot]

Yeah, looks good.  We need to post more VUE renders so Matt gives us more relevant teasers

I echo the point to:  If you can tell us what is different in the clouds, new features or methods or nodes or noise types or anything.

[domdib]

Looks great.

[Matt]

Kadri, there is one new cloud parameter that allows the samples to skip over large volumes of empty space, but I didn't use it here. With this render, the main difference between how it renders in 2.0 and 2.1 is that I ray-traced the pixels, rather than breaking the background sphere into micropolygons and shading those. This is done using a new option called "ray trace everything". For most landscape scenes you still need to use the old rendering mode, but it wouldn't have made a huge difference on this scene anyway.

So basically these clouds are possible in 2.0. I'll post an example scene soon.

Apart from that, not much has changed in the clouds for 2.1. The biggest thing we've been working on is "ray trace objects", which improves quality and speed of your imported objects and vegetation, especially populations. It also means we avoid some of the bugs in the old population rendering engine which we think may have caused many of the render errors people were seeing.

[Kadri]

Wow thanks Matt.
I have to read it more than ones to really understand .
Matt if i may ask another question , by render errors do you mean the black triangles or errors on imported objects (obj ...) ?

I think your new method is really faster?
I have seen the render engine wasting times  behind object rendering . İs this new method affecting this render behavior too?

Thanks.

Kadri.

[Matt]

Matt if i may ask another question , by render errors do you mean the black triangles or errors on imported objects (obj ...) ?

We think it may avoid bugs that caused some buckets not to complete when they contained populations. There were some weird issues we couldn't figure out with the old renderer. The black triangles are a different problem which we're investigating right now.

I think your new method is really faster?
I have sean the render engine wasting times  behind object rendering . İs this new method affecting this render behavior too?

Rendering the terrain using ray tracing has its own problems. Usually terrain is more efficient and renders with higher quality with the old method, despite the overlap. For that reason, the default settings in 2.1 are to use a hybrid approach, using ray tracing for objects and using the old micropolygon rasteriser for the terrain, background and other displacement-friendly surfaces.

Matt

[Kadri]

I think i know what you mean with  " Rendering the terrain using ray tracing has its own problems. Usually terrain is more efficient and renders with higher quality with the old method, despite the overlap. For that reason, the default settings in 2.1 are to use a hybrid approach, using ray tracing for objects and using the old micropolygon rasteriser for the terrain, background and other displacement-friendly surfaces. "  I know the behavior of the renderer on landscapes sometimes(back rendering?) But my english might mislead me.

My question was more like  : Think of a big imported object (obj) in front and very big (1/3 of the render size or so) the render engine computes the back side of the object(the landscape or clouds behind) too.

No more questions tonight i promise  

Thanks Matt.

Kadri.

[CCC]

All that is really missing for clouds are two things i think. Multiple internal light scattering and a way to create very finely detailed edge feathering effects.    

[domdib]

Just out of curiosity, why was internal scattering removed completely, rather than retained as an option with the caveat that it increases render time?

[Matt]

Just out of curiosity, why was internal scattering removed completely, rather than retained as an option with the caveat that it increases render time?

It does not increase render time. Fake internal scattering is a local point-based cheat that changes the lighting contribution without expensive calculations. The reason it was removed (only for GI contributions) is because I realised it was wrong in most situations, creating the "oily look" that people were complaining about. It still works with direct lighting (e.g. sunlight), so I didn't want to change the default setting to 0. The easiest thing was to disable its effect on GI contribution until I work out a more realistic implementation. I am trying to make sure that clouds being created now will look similar (but automatically improved) when they are re-rendered in future versions, without having to add too many switches in the GUI to maintain backward/forward compatibility.

[Gannaingh]

Nice clouds! It's good to hear about all the improvements that you guys have been working one. Thank you for all of your hard work; I look forward to the next release 

[Henry Blewer]

There is a North Easter south-east of here. The clouds over head here in Binghamton looked very similar; and I was wondering how to make them. I considered using a mask, but now I'll just wait and let you do the work.
Very good render Matt. It is nice to see that you use your software. I bet everyone would like for you to do more of this. (Get an old Pentium 4 HT. It leaves lots of time to program )