Bu aspen.
First of all, simple particles and strands from Blender are not supported in Yafray yet. So you have todo convert your particle system into a consistent Mesh which Will be than renderable in Yafray. You can apply an object todo particle system, and than you get the particles renderable, without converting them todo a Mesh (because system already use objects in system). The techniqe may be used todo creating golf Grass, normal Grass, tropical Grass, it a los god todo use todo carpets, and animal Fur. First im gonna todo show you how todo create god looking Grass in Yafray. Second part Will be about how todo create human hairs, which are a Little bit diferent than Grass.
simple Grass.
1. Open Blender and remove all your objects.
2. Add new plane which Will be a basis for our particle system.
3. Go todo the particle buttons and create new particle system.
4. In particle system box change from emitter todo Hair.
5. In physics box set normal value todo 0.1 the same as random value our particles are more diestorted, and looks more like a real Grass.
6. Change Brown value todo 0.05 todo randomize our Grass Even more.
7. In visualization box you can change steps value from 2 todo 3 (this changes the quality of Grass particles, higher = smoother = longer render time)
8. In editing panel and modifiers box convert particle system todo a Mesh.
9. Split 3d view área and choose in window type: scripts window.
10. Now in scripts menú choose Mesh -> Edges todo curve.
Remember, that it Will take a while before all Edges are converted todo curves (from few seconds up to few minutes depending on cpu speed).
11. Now in editing (f9) panel and curve and surface box, marque bak and front and change extrude value todo 0.01 and defresoulu todo 1.
12. Press Alt+c in the 3d view and press LMB.
So, now youre done and can put some materiales on the Grass. These are my settings of simple Grass material.
You should get the same result as on picture below:
advanced Grass.
The second method is a Little bit harder, but you get better results as well. Now im gonna todo use an object todo be emitted from an emitter as particles, gracias todo this method you can Simply map your Grass strands todo UV texture. Lets start:
1. You remove all your objects and add new plane.
2. Go todo the particles and add new system.
3. Change in particle system box type of our particles from emitter todo Hair.
4. In physics box set value of normal todo 0.5 and random todo 0.3 (or if you want you can increase/decrease the value of randomized particles).
5. Go todo the second layer (button 2 on your main keyboard, not the numeric one.) and add new plane. Lets create simple Grass strand which Will be emitted from your first plane, you can actually use Whatever object you want, it can be simple Grass strands, it can be flowers or some wed and than you can combine these particle systems together todo get realistic result.
6. Go todo Edit Mode of this plane and scale it along x axis 0.1 times.
7. Control + r and rotate mouse whel until you get 4 cuts (you can just type 4 on numeric keyboard under cutting).
8. Marque these 2 vértices on top and choose Sharp fallof.
(o key) and scale them by x axis todo zero (you can adjust the affect of modifier on Mesh by spinning mouse whel).
9. Cut your Grass strand in the middle (Control + r along y axis) and move marked verices -0.04 along z axis (remember todo set of fall of at this moment).
10. Scale the top of the Mesh by z axis a los using fallof, y a los scale the object twice along y axis todo have longer Grass strands, press n button than you get object properties, in my case the name is plane.001 so copy the name of the object (Control + c) (under time you can set Smooth on object so its smoother).
11. Rotate the plane 90 Degrees clockwise so the Sharp top is pointing 3 oclock. You can add UV texture todo your Grass strand by from the top view pressing u button and chosing Project from view and in the UV image editor selecting texture you want todo use on your Mesh and Pinning your Mesh onto texture with p button.
12. Go todo your 1 layer, marque the particle plane and change in visualization box from Path todo object and paste the name of Grass strand (in my case) plane.001.
13. You can make these two layers todo make them visible by holding shift and Marking first two layers. Marque (RMB) your Grass strand and scale untill you get a result you are expecting (i scaled with 0.1) and move along x axis todo adjust particles position on the plane.
14. Your Grass is renderable by Yafray right now, but lets say, that you want todo add some modifiers on your Grass, so what todo do? Lets add some faq Wind just todo create more realistic behavior of our Grass. But first convert your particle system (editing (f9) -> modifiers box -> convert) and join them together Control +. Add new lattice, scale just over the Grass and move over Grass.
15. Set lattice points of w direction todo 10.
16. Now marque your Grass and add modifier lattice and define lattice object name (in my case the name is Simply lattice).
17. Marque lattice and go todo the Edit Mode, marque vértices in top of the lattice and move them lets say along x axis with Sharp fallof enabled.
18. You are done now with modeling part it time todo go todo the rendering part. Dont forget about Camera. Lighting: i used AO with 10 distance and.
Light blue bg and AO color and sunlamp (yellow of course) angle 2.
19. These are my settings of Grass material.
20. Just press the render button and it done.
Here is the result i get:
God luck.
Last very importand thing is that you can use groups instead of simple object mapping. You can add diferent meshes faster (like diferent Grass types, flowers, wed and Stuff like that) and have control over them by adding them into groups (object (f7) panel and object and enlaces panel, you have todo change visualization from object todo group in particle system panel to, and add the name of group you want todo add), and finally map them on your Ground.
Here is very handful guide about particles in Blender, which can be an addition todo this tutorial.
Http://www.cgcokie.com/articles/painting-instanced-objects-into-your-bl.
Here is the enlace todo blend file with UV mapped Grass and group mapped particles:
Http://www.Yafray.org/sites/default/files/grassadvanced, blend.
The video from my workflow Will come son.
Blend file : grassimple
Blend file : grass_advanced.
Origen: www.Yafray.org/documentation/tutoriales/particles1.
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