Hi People,i'm Italian and so,sorry for my bad English!
i've a question:
it's possible, using brazil for rhino, create a material for a grass field with many different tufts?
i think it's possible using a bump map, but i don't know how to make a realistic grass material!
thank for all your suggestions!
You could just use a texture map for the color. The bump map may not even be noticed unless your view was very close to the ground. The important part is making sure that the image you use will tile seamlessly. This requires some upfront 2D work. You can find a grass material in this collection as well... http://brazil.mcneel.com/photo/architectural-materials-1
there's a problem with "grass material" !
when i load it inside rhino,and try to render a hill(for example) the bump is not working fine,cause the grass seems flat,in other words not in rilief!
at right an image in post production,using photoshop!
The grass is flat aside from a slight bump. It's only a texture map (a photograph) used for both the color and bump channels. You can raise the bump amount from 20% to 100% but it will not create blades of grass sticking straight up. For that, you'd need to actually model the geometry of the grass and this will require a lot more time when rendering. You can also try displacement meshes based on images of grass. You could use NURBS as well for displacement but the density of your render mesh should be kept as low as possible if that's the method you choose.
using material menu under brazil,it's impossible obtain a grass blade!
so,i've an idea:
i tried to modeling single blades in my scene,a blade= a surface,that i copy many times,to cover a field(1x1m for example)!
this's the result:
the problem,using this solution, is the rendering time!
for this scene, with a red cube,a field(a surface with texture applied) and several blade of grass,modeling by hand,my pc take on 5 minutes to rendering it!
but the result,i think,is very good!
how improve the grass yield!
i'm not satisfied yet!!
I have never successfully done a grass with individual blades like this. In architectural rendering you usually need to take one of three approaches to grass:
1. Keep your camera far enough away that you can use a flat material and it won't be a problem.
2. (Can be combined with one) Spray in the texture in Photoshop - use the stamp tool from one or more photographs (ideally, a photo where a grass field is in perspective, so that you can spray in the foreground, midground, background at the right scales). This is really the most reliable and flexible method, period, and I suggest you look into it in more depth! Your Photoshopped image above is just not very resolved yet... I think if you take another couple of hours to find the right source images, and really master the stamp tool, you will get great results!
3. You can try modeling grass. Doing it yourself (like in the image above) is very brave! In fact there are plugins for many modeling programs that will generate grass. Yes, the amount of geometry is a huge problem, and the lack of *variety* makes the result seem kind of unrealistic, usually. Programs/plugins like Speedtree have ways of addressing this, I think, by combining clusters of geometry with texture maps.
Basically it's a hard thing to do really properly without good Photoshop skills, which is why nobody can easily answer your question, I think.
thanks for your answer!!!
i know a method using photoshop for create a grass field,but it's very expensive in term of time,and a bit unrealistic!
you must select background,and after,using a special kind of brush,that you find inside photoshop by default,fill the field with it!
That's an interesting effect, which I don't think I've seen before. For a particular style of rendering, I think this could work really well! But, if you want more realism, I still think the best way is to use the stamp tool in Photoshop to apply images of real grass from photos.
And, yes, quite expensive in terms of time (human effort)! But you could probably get it down to 1/2 hour or 1 hour per image, once you have practiced it enough.
Good luck with whichever method you choose.
I tried to make a grass field following the approachs from this discussion.
as u see, 'bump' cant create a realistic grass-blades straight up...
I even tried using the displacement from R5, but it dosent works very well for this case....maybe for the wall/stone it works fine, but not for grass...
I notic that we also could use brazil analytic bump..it works similar like displacement in r5...but it still dont helpt to get raised texture on the edges...
I saw some example from this website: http://brazil-rs.blogspot.de/2008/07/making-grass-with-displacement...
Do u think so, that we also can make this by using brazil for rhino as well?
Brian James said: