Realistic Grass Anyone????

[watso75]

Hi guys

I am a landscape architect and am using 3ds max 9, Can anyone help me out with the most efficent way to produce realistic grass for my scene. I have used a few tutorials in the past which produces high number of polygons in my scene and can not produce a good enough effect of really short cut grass over a large area, the file size gets large and there are too many elemnts. Can anyone help out there?

PS I often use the standard short grass in materiel library but think there must be a better way

thanks in advance8)

[craigp]

My way is to attach this grass texture to your object / plane and in the texture menu, add the same image for a bump map. To create the bump map, use photoshop to make a copy of the texture, change it to black and white then up the contrast and save as the samr format and size etc... Now use this as your bump.

If you use vray, please let me know and I will send you a great link for VRAY textures which will give you all the necessary texture maps for a brill grass texture.

[Cad64]

I use the same method as Craigp, but I also throw the bump map into the Displacement slot to add a little more volume to the grass. I haven't played with the realistic grass feature yet, but I figured it would be pretty processor intensive, so I would probably only use it for small areas up close to the camera. Definitely not for a whole field.

[watso75]

cheers guys, i dont use vray so will play about with what i got. I tried to render a whole field once, less said the better i think:shock:

[watso75]

My way is to attach this grass texture to your object / plane and in the texture menu, add the same image for a bump map. To create the bump map, use photoshop to make a copy of the texture, change it to black and white then up the contrast and save as the samr format and size etc... Now use this as your bump.

If you use vray, please let me know and I will send you a great link for VRAY textures which will give you all the necessary texture maps for a brill grass texture.

How do i know what colour to be black and what colour to be white? Probab an easy answer but hey when u dont know you dont know?

[Cad64]

It'll be obvious when you desaturate your grass image. You'll get black, white and shades of grey automatically. The black parts will be the parts that will be recessed in the bump map, the white parts will be the parts that bump up in the map and the grey bits will fall somewhere in between. You will want the map to be mostly black and white though, so that's where the contrast comes into play. You can adjust this with "Levels" or "Curves" in Photoshop.

[watso75]

sorry about this, finding my photshop knowledge lacking here, desaturate? how do you do that?

[watso75]

ok found it, image, adjustment, desaturate.
Thanks anyway everyone

[craigp]

No problem like CAD mensioned, the best way for clser detailed area's is the displacement method, this gives brilliant results however you do need a good setup to render this at speed.

[wbroberts]

displacement grass is not what you want....the effects are not distinguishable from bump map for typical arch viz applications and they take ten times as long to render......I've spent a lot of time screwing around with grass and I believe, as already mentioned, taking two separate grass maps and mixing them in a smoke or noise slot then using a procedural bump such as cellular or dent works best and looks like a picture perfect lawn....
displacement grass is good for overgrown or small patch areas that you want to be part of your "flair".....

[watso75]

displacement grass is not what you want....the effects are not distinguishable from bump map for typical arch viz applications and they take ten times as long to render......I've spent a lot of time screwing around with grass and I believe, as already mentioned, taking two separate grass maps and mixing them in a smoke or noise slot then using a procedural bump such as cellular or dent works best and looks like a picture perfect lawn....
displacement grass is good for overgrown or small patch areas that you want to be part of your "flair".....

cheers, any chance of some pointers to a tutorial, i kind of get what you mean but think i need to follow a tutorial. I'm a Landscape architect and this is possibly the hardest part of my visuals, any help much appreciated

[wbroberts]

I'm not sure about tutorials online for this.....I've searched for years and have only found bits and pieces....there is a lot on displacement grass tutorials......but for some reason it is a "trade secret" or something.....

these are the settings I used to do this rendering i'm working on right now....it is a MR Arch & Design shader; with smoke in the diffuse slot using two separate grass maps, that gets rid of the tiling and gives you that natural mix of shades and texture....darken your image maps Output RGB level to something .5 or .4 (<--that's an important step!).....you can use a bump map such as Cellular at a tiny size (.1)...the example image uses a normal map of grass that I created with an Nvidia PS plugin from a grass b&w image....but I'm not going into that since it is a shader i'm developing for my own arch viz business......that's about it

...of course there are probably a million different combinations to achieve this look.....ie noise maps, mix map et al

These attached grass maps have worked very well for me (and others) in the past by making them about 8' wide and mixing them in the slots.....experimenting with different texture images is the best way to go about you scenes....
42184220

[watso75]

thanks, will give it a try. Nice visual by the way

[hazardman]

if you have the processing power and time to wait you could alway use the hair & fur plugin...there's even a setting for grass...never was sucessfull with a full feild of this stuff but in small patches and/or foreground work is seems to be ok...

you could also model a few strands w/ line shapes and use the scatter in the compound object create panel...

but in the end, yeah, grass is hard to do especially if you're going witht the strand/wispy look...

[Cad64]

Just found this tutorial posted on another site: http://jeffpatton.net/MR_Grass_Displacement.htm

[wbroberts]

Just found this tutorial posted on another site: http://jeffpatton.net/MR_Grass_Displacement.htm



yeah, that is a very good tutorial on the process.....it helped me with the concept of MR micro displacement years back.....as it is a processor-hungry procedure, render optimization is the key to grass displacement.....as anyone will warn you though, avoid large "fields" and use it in the foreground with either falloffs or masks to regular bitmapped grass in the receding distance....I use it for my sites in the parking islands and front lawns et al.....I finally got this 800x600 test to 01:30 via optimizing the model and renderer this past year....

[wbroberts]

yeah, that is a very good tutorial on the process.....it helped me with the concept of MR micro displacement years back.....as it is a processor-hungry procedure, render optimization is the key to grass displacement.....as anyone will warn you though, avoid large "fields" and use it in the foreground with either falloffs or masks to regular bitmapped grass in the receding distance....I use it for my sites in the parking islands and front lawns et al.....I finally got this 800x600 test to 01:30 via optimizing the model and renderer this past year....


......but this is the future for grass....parallax normal relief mapping....it renders so fast....40 seconds for this test...but it doesn't support mental ray...just vray and scanline (this test)....this would work for a field.....

[Cad64]

...but it doesn't support mental ray...just vray and scanline

:o That's some nice looking grass, and so fast too! But I don't have Vray and I prefer Mental Ray over scanline, so I guess I'll just have to keep doing it the way I've been doing it. :(

[wbroberts]

:o That's some nice looking grass, and so fast too! But I don't have Vray and I prefer Mental Ray over scanline, so I guess I'll just have to keep doing it the way I've been doing it. :(

....yeah, i prefer MR to scanline too, but writing plugins that run with that render engine are very difficult....i never learned scanline well enough to get the results that some got from it back in the day either....but I believe that this new steep parallax technology is the solution to a lot of the current texturing problems people experience with arch viz today since it avoids the memory hungry micro subdivisions required with decent displacement et al..that plane in the test has two faces!.....anyone know mental ray code well enough????

[TwiiK]

The sole reason I registered here is so I could force you, wbroberts, to tell me how you made that field of grass. :lol:

I'm mainly using MR, but I guess I could render just my grass in scanline if it's as fast as you say.

You feel like sharing your secret or the plugin you used? :)

Edit: Ohh, think I found it.

Is it Fabio Policarpo's Relief Mapping plugin v.1.8 you're using? I tested it in scanline now and it even works in max 2008. Good times. :)

Edit2: I've been testing it some now and while I get good results with the usual brick and tile texture, grass is not giving me good results. It's not getting any height at all. Would you be so kind as to show me the map you used for getting those results? Mainly the normal/depth map.

Thanks.

[wbroberts]

The sole reason I registered here is so I could force you, wbroberts, to tell me how you made that field of grass. :lol:

I'm mainly using MR, but I guess I could render just my grass in scanline if it's as fast as you say.

You feel like sharing your secret or the plugin you used? :)

Edit: Ohh, think I found it.

Is it Fabio Policarpo's Relief Mapping plugin v.1.8 you're using? I tested it in scanline now and it even works in max 2008. Good times. :)

Edit2: I've been testing it some now and while I get good results with the usual brick and tile texture, grass is not giving me good results. It's not getting any height at all. Would you be so kind as to show me the map you used for getting those results? Mainly the normal/depth map.

Thanks.

I'm glad to see others are as bothered by this age old problem of grass as I am.....
Yes, that plugin works the best with some tweaking....there is still a problem with it when you get into silhouttes on NURBS type surface meshes etc.....it handles curves and planes fine.....but those silhoutte details are important around structures etc for grass....I've attached my settings....you can just use his stone (with the tiling set pretty small which resembles Max's cellular procedural) or create normal with depth mapping with the Nvidia normal plugin for photoshop.....or GIMP has one too....I could attach my own grass shader later if needed....just real busy getting a building modeled right now.....but I find it very encouraging that I can get these results in 41 seconds.....

[Cad64]

I'm reviving this old thread in the hopes that Wbroberts will come back and share his plug-in with us.

Wbroberts, you out there? :unsure:

[melox]

Can't find grass in my materials library. It was there, I've seen it before. Can anyone help.
Is it something I've done?

[Cad64]

Yes, it's there.
It's in the architectural.materials.sitework.mat file. There are two grass materials.

[melox]

Thanks CAD64. Got it. Now I'm going to put grass on everything. Except where the grass should be and concrete that bit.

[BenGoble]

http://www.mrmaterials.com/jeffs-blog/101-mrproxy-grass.html

Just thought I'd tag this on to this post as it's pretty damn good.