Particles in Yafaray (grass)

[Aspen]

Hi, I did tutorial about renderable particles in Yafaray, and i want that You help me improve the quality of tutorial. First part is very easy (often for someone who can't handle Blender UI so good) and second more advanced and with better grass quality.

Here is the link to the tutorial
http://aspen.darkstyle.com.mx/Particles ... 1_beta.pdf

And fast preview of results
easy mode


blend file: http://aspen.darkstyle.com.mx/grass_simple.blend
size: 3 MB


advanced mode


blend file: http://aspen.darkstyle.com.mx/grass_advanced.blend
size: 13 MB

Thanks to DarkTide for his server space

[Arkinauta]

Many thanks for the tutorial and the resources. I found it quite handy!
Why don´t you post it in the tutorials section?

Greetings and thanks another time!

[Aspen]

it's still beta, i did some ortographic faults + i have to add tutorial about particles as human hairs (which im working on right now).
Anyway, it's cool that someone liked it, i will do my best to finish the tutorial as fast as it's possible

[Samo]

Anyway, it's cool that someone liked it...

We all like it. I only think it needs an introductory section, talking about what is supported, what you can do with it and use cases.

Thank you for you collaboration!

[wizofboz]

I found your work interesting too. It has some cool things that I never thought of.

You probably know this already, but I sometimes find it useful to work with the converted particle data as a curve object rather than a mesh. After you convert the particle data to a mesh, in edit mode with the resulting mesh you can use the edges to curve script (Mesh > Scripts > Edges to Curve) to get a curve object. If you've done this before then you probably know that the script can be slow converting meshes with lots of vertices.

From here you can extrude or bevel the curve, or use a bevel curve/taper curve. Of course this curve object must also be converted to mesh before you render it in yafaray.

The obvious disadvantage to this method is it tends to producea very dense mesh in the end (lots of vertices), although there are ways to control this somewhat. Anyway, it's just another way to get yafaray to render particles.

[bupla]

Thanks Aspen for this tutorial. It's good to explain a workaround to expand Yafaray current features.
I use this technique too, but I'm used to select Group visualisation instead of Object for the emitter.
Maybe could you add this possibility at the end? With it, you can make several grass types, plants, etc, group them and use them as a base for your emitter.
Also, you could add a link to this tutorial by Kernon Dillon: “Painting Instanced Objects” http://www.cgcookie.com/articles/painting-instanced-objects-into-your-blender-scene,
it works very well with Yafaray and fits with your topic.

[Aspen]

thanx a lot guys for your replies

Samo: You're right, i should absolutely add introduction and explain in the begginning what's supported, it would be very usefull for people who use the tutorial

wizofboz: yes, i tried with converted curves too, but I knew that Yafaray don't support curves (otherwise we could get renderable particles as curves ) and thats why i found out thats it's a lot easier to make them just like simple object, not curve converting, but sure, beveling a curve is very good type to make hairs, hmmm yep, thanx a lot wizofboz, i've just got an fantastic idea, which I'm gonna add to the tutorial.

bupla: No problem, sure i will add it and I will also write about Groups, it's gonna be a loooong tutorial I guess

thanks again guys

[Manuel_Ramos]

Does anyone here know the maximum amount of hair particles one can get without a crash?
Is this related with the number of meshes we have in our object that is being copied by the particle system?

Dont know why but I get a crash with an amount of 3000...

[Aspen]

Manuel_Ramos: it depends on how powerfull your computer is, in viewport RAM memory (videocard memory too) and under rendering RAM and CPU. But maybe its not so important as quality of particles, i had 8 faces/strand its pretty low, but I sucessfuly rendered 80 000 of grass strands like that, so its important that they are low poly . Secondly, blender crashed under 40 000 when i rendered normally, when i runned Blender from terminal, it rendered much faster and could calculate more particles, so maybe its better to start blender from console if you want to render a lot of particles

[Manuel_Ramos]

Thank you very much for the tips Aspen.

But I m afraid It is some kind of bug.

When I render the same thing with blender internal, it renders fine.
On the other hand, I tried the same thing on a pentium VI and a pentium II. It crashed ecactly at the same amount of particles.
I also tested version 305 for linux (32) and 305 windows 32. They crashed at the same amount.

Here is the error message when the amount is 4000. (When the amount is 2000 it just crashes, no message. When the amount is 500 it renders.)
http://rapidshare.com/files/250696199/teste.JPG

Here is the file. (you just need to turn particles visible in the particles panel. Otherwise the file would have 60 mb!)
http://rapidshare.com/files/250695342/teste_2.blend

Thanks in advance for your help

[Manuel_Ramos]

It would be nice to see who gets the best amount renderable and why.
Otherwise, its just a bug, right?

[Aspen]

hm.. I looked at your file and found out that you used Faces children which i didn't wrote in my tutorial. So you used 4000 particles multiplicate by 300 which means 4 000 * 300 = 1 200 000 . Talk about really good computer to generate over a miljon particles (human avarage hair number is 100 000 and i think its too many to render it anyway ;/) When i enabled visualization of particles my computer hanged immediatly . I choosen 10 particles to generate and found out that there is absolutely too many (3000) grass strands. The solution is to not use face children or use less amount in Basics particles. I generated 100 000 without any problems, and i hope that it helps you later (max amount of particles depends on your Ram memory and CPU and in 3D view of memory of your videocard)

Its not a bug

[Manuel_Ramos]

Hi Aspen. Thanks for the reply.
Glad to know that there is no bug!
Yup, I think we have too much particles for our computers

Nevertheless, how can I make grass in a field with 100m x 100m?
We need that amount of particles right?
I also think that even with this big amount of particles the grass is too big and we dont get enough realism.
Have you got any ideas?

[Aspen]

use just 100 000 of them, i guess with this perspective and this angle you should get nice result, otherwise you can split your particles to lets say 3 different types, the first one closest the camera gets more particles, some "meter" farther you can locate the second particle system with less amount of particles and the same thing with 3th one. Thanks to this technique, you can render long distances with particles

[Manuel_Ramos]

Thanks aspen.
I will try that one