Constant Variable (Rue Gallait 80 1030 Schaerbeek)
Start at 10:00 until 18:00.
For non french speakers : I don’t speak english very well but if you’re interested to come, don’t be afraid. I’ll do my best to explain in both languages and @quenting and @collignon_david could help me in this task? 🙂
L’an passé, j’avais donné un Workshop sur le Node Editor de Blender principalement axé sur le compositing.
Cette année, je propose toujours d’explorer le Node Editor, mais avec Cycles en expliquant ce que font les differents nodes et shaders, comment paramétrer Cycles avec les petits trucs que j’ai pu trouver pour éviter le bruit et artefacts.
J’essaierai d’être moins dense que l’année passée, en proposant de tester un peu plus Cycles au fur et à mesure ou de faire la théorie au matin et quelques exercices l’après midi. Prenez donc vos machines!
Si vous voulez savoir faire quelques chose en particulier, n’hésitez à
me le demander ici à l’avance que je puisse un peu voir ça.
I have several points with examples for reducing noise and decrease render time. I’ve gathered tricks I found, hope I’ll learn you new things.
What do you want to know exactly about smoke and fire? It’s fairly new and the implementation is not finished yet in Blender. Anyway I can show you a node setup to use it. Is it OK or you’d like to know more about it?
smoke and fire is indeed a difficult one, so I second David on that one.
Perhaps it would also be interesting to start of with a short overview of some of the information we have at our disposal in cycles. I mean: the different rays, object information, ray length, particle lifetimes, … stuff like that.
Fur and hair would be interesting as well.
Oh and could you also explain once more the logical way of combining some of the basic textures? I mean things like: you should normaly add a diffuse and glossy shader and not mix them. I know this is very basic, but I feel like I’m stuck in the BI. How do I use that velvet shader? Just on its own, or do I combine it with another shader?
More questions will pop up during the workshop.
Fur and smoke are quite easy to setup. I didn’t play a lot with that but a few nodes was enough to get result when I tested it. We’ll see that during the workshop, that’s not what I know the most 😉
I’ve prepared some files with different render settings to realize what does what. Hope it helps.
For the combination of shaders, I propose that everyone try it in the afternoon, I’ll bring some files to play with.
A velvet shader, or any shader, is almost never used alone. Any real object has a part of diffuse, of glossy, translucence, etc. If you wish, you could try during the workshop to reproduce something similar to the BI shader in a nice Cycles node group. It could be very fun to do and even useful in all your projects.
I just wanted to let you know that I will be arriving at the trainstation at 9:51. So, counting on some kind of delay and then the walk to location, … I might be there shortly past 10. Hope nobody minds.
First of all: thanks a lot guys, I really learned a lot from this workshop.
I think the things we learned about homogeneous and heterogeneous and about using the volumetrics are quite interesting. And I started to think that It might be interesting for the rest of the community as well. So I wondered if you guys would agree to pour this into a short tutorial on the subject?
I volunteer for the recording and everything, so you guys don’t really have to do anything anymore except give pointers and judge the result. Unless some else has better recording equipment or so.
This could also help the BBUG to become more known in the community. What do you guys think?
a short question:
when using a cylinder with volume scattering, I remember something about moving the camera into the cylinder and flipping the normals. But that doesn’t seem to work for me. It is also stated in the docs that putting your camera into the volume is not going to work.
I did some more tests and I got the volume scattering figured out. The volume aborption is still a bit weird. Is there anyone with a nice scene that can make me help understand why it does what it does?
During the workshop you asked where the name for the blackbody node came from. I didn’t really explain it properly, so allow me to do that now:
A black body is defined as an object that absorbs ALL radiation that hits it. Which is off course an idealisation of reality. We call it black because of this property to absorbe everything.
Obviously it is impossible to keep absorping all kinds of radiation because the energy has to go somewhere. So the black body heats up. If something becomes warm, it will emit light in order to cool down again and this emitted light follows the black-body spectrum (also called the Planck spectrum). This spectrum depends on a temperature. This temperature is the equilibrium when the amount of energy absorbed is equal to the amount emitted.
What is special about the blackbody spectrum is that it is completely independent of the object. Every object will emit this radiation independent of size, shape or composition (except when there are extra chemical reactions or so taking place). It also doesn’t depend on what kind of radiation you send in. Only on the amount of energy you put in each second.
The spectrum itself is not a very difficult formula. however, in order to derive it you will need quantum mechanics and in fact the succes of the Planck spectrum was one of the first successes of quantum mechanics in the 1920’s.
Where would you use it? I think the most logical place is for lights or other emitting objects that are quite hot. eg. metals in a furnace. the tungsten wires in a light bulb. Perhaps a sun or other hot selectial body, …
I hope that this clarifies things a bit.
Hey guys, I made a first recording for the tutorial this evening, which I will try to edit tomorow.
Great Nick 🙂
It’s really nice to play with the volumetrics, animate the settings et see the result.
For your questions, I just inverted the normals and it was working. If you take the files I gave you during the workshop, it works with the volumetric examples. But Maybe it doesn’t work in any cases. Can you upload your example? I’d like to know when it works and when it doesn’t.
Does someone has an idea how to animate the normal direction? The AnimAll addon doesn’t seem to animate that.
I have tried several times with different volumes. The easiest being a simple cone with homogeneous volume. But I also tried with the emission volumes. None of them all seem to work for me.
Try that : http://www.vincentgires.com/divers/volume_material_normal.blend
The first cube is with the normals in the default direction, volume can be displayed only from outside. The second cube is with flipped normals and we can see the volume even if the camera is inside the cube.
So, what I noticed: the flip normals only seems to work if you put the number of volumetric light paths higher than 0. From outside, with the normals pointing outward, volumetric paths = 0 works fine. Going in makes the volume dissapear, no matter what the direction of the normals is. If you set the number of bounces higher, then the inside indeed seems to work if you flip the normals.
However, when you flip the normals, the volume sometimes changes drastically from the outside, so use with caution.
To all, about the tutorial.
It sounds ambitious to me and, of course, super cool.
If you do that, Kudos, congrats and the like ^^
All the steps seems logical to me.
It might already be an one hour long tutorial, no ?
Live & Learn
it took me a lot of time today to get the tutorial working. Apparently my screen and audio capture software doesn’t like it that I use cycles while recording.
Anyway, I think I got the whole thing together in something like 21 minutes.
I have posted it on youtube privately: http://youtu.be/PHL3qNAQuGE. Normally you should be able to see this. Don’t share it yet, I will make it public soon via the Blender Education channel, but in this way you can already see it, see the caption I wrote for it and give some feedback.
I know it is not the best tutorial around, but it is my first time, so be gentle 🙂
What do you think?
Very nice Nick!
Thank you 🙂
I have only on thing to say about the tutorial is the length. Maybe it’s because I play with that too but I found it a bit too long. It would be nice to segment the chapters into different videos maybe? like A. volumetric light, B. objects shaders (emission/scatter/absortion) and C. Hetero/homogeneous.
do you mean actually cutting it up in different video’s?
Your tuts is better!! (shameless self promotion ^__-)
Thank you for doing this. Is there a way to add multiple audio tracks on YT ?
Maybe we could do a French and a Dutch alternate audio. Most likely too much work but still…
Anyway, It’s über cool. Publish it so we can brag about it ^__-
Live & Learn
As far as I know, there is no way to add different audio tracks on YT. You can add subtitles if you want to.
Haha, go ahead with your video 😉
Actually, I like what they dit here : http://blenderdiplom.com/en/tutorials/419-tutorial-absorption-in-cycles.html
A table of content to know where to look in the video is just fine.
Oeps, it is in dutch, so let me translate a bit:
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