Grass-o-matic Settings

[Wrender]

Hello everybody!

 

I'm looking for a good source of grass-o-matic settings to use in my renders. I did a quick search and didn't come up with much. If this already exists, please point me in the right direction.

 

I'd like to get a one stop shop for settings that create multiple varieties of grasses ranging from tight manicured lawns, to wild glades, to unkempt half dead fields. I'd also like to get a good mix of render "type" settings to include bird's eye, up close, medium range to help out with render time optimization.

 

Beyond this, my wishlist would include a premade max file with all these types laid out, so you can simply merge the grass-o-matic object into your scene, adjust the blade count, and you're done.

 

Any help would be greatly appreciated!

[Claudio Branch]

http://www.happy-digital.com/autograss/

[Wrender]

Thanks for the post Claudio - but I'm looking for a mental ray solution - specifically Grass-O-Matic. I'm not looking for other Grass renderings methods. Any ideas?

[Claudio Branch]

My Bad - I wasn't aware that g-o-m is an an actual plug-in. I thought you were just saying you needed something fast and easy. Who makes the plug-in?

[Wrender]

Sisyphus Software - it has since become freeware. You can d/l it here:

 

http://www.maxplugins.de/max2011.php?search=&sort=Author

 

Just search for "Grass-o-Matic"

[jinsley]

I would be wary of using grass-o-matic if you are planning on making proxies of it and distributing it over large areas...

 

I don't know why, but it has caused me and others problems in the past... maybe that has changed now with later releases, but I would look at peter guthrie's blog and see how he is modeling his grass proxies...

[jinsley]

sorry, I was looking back through my notes quickly.

 

GOM is not the problem, you just have to remember to reset x form before converting it to a proxy.

 

Which you should do with all your proxies anyways... so my bad.

 

I think I remember Jeff Patton was saying that with GOM he uses the same patch to generate a few varied patches which he attachs and then converts to mr proxy.

 

my notes on proxies and mr are here:

 

http://forums.cgarchitect.com/37505-grass-test-using-particle-flow-mr.html

 

towards the end of the thread...

[Wrender]

Thanks Jinsley - that's actually the same workflow I use. GOM to make patches, and then mr proxy into scene.

 

However, what I'm really after, is a series of premade proxies for difference scene types - ranging from tight manicured lawns, to unruly meadows. Sort of an index of grass types. It's time consuming to make a good GOM settings blend for each project - just curious why we're constantly reinventing the wheel, when as a collective, I bet we have several settings already made.

 

For instance, can somebody post GOM settings for a really good 5' x 5' lawn? From which we can make the object, and proxy into scene?

[Nic H]

you would get better, quicker, more flexible results using multiscatter and the i-grass pack from rendering.ru

you don't even need to convert to proxy just pick the meshes and base object and thats basically it.

 

(i know its not using grass-o-matic, but its a very easy, high quality solution - albeit more expensive)

[jinsley]

you would get better, quicker, more flexible results using multiscatter and the i-grass pack from rendering.ru

you don't even need to convert to proxy just pick the meshes and base object and thats basically it.

 

(i know its not using grass-o-matic, but its a very easy, high quality solution - albeit more expensive)

 

how long have you been using the i grass nic? Is it a daily tool, worth the purchase? any examples of scenes where yo have used it?

[Devin Johnston]

http://www.happy-digital.com/autograss/

 

Claudio have you actually used this plugin? I purchased it 9 months ago and I wish I haden't it's increadabley slow and unstable compared displacement or proxy's.

[Claudio Branch]

I have not...I use Forest Pro 3 for grass, trees, riprap, everything...

[TSuess]

My tutorial on how to effectively use Grass-O-matic for manicured lawns and grasses is HERE!

[dande]

I use grass-o-matic . Like yourself I have not been able to find any standard settings so I just play around with it. Then I convert the grass-o-matic to a mesh and add a reset Xform. Then create a proxy The reason I add a reset xform is because I have seen Max render out the grass incorrectly. For example I recently forgot to add the reset xformand when I rendered the scene the grass looked like a hedge.

 

To scatter I use forest pack lite or Peter Watje's scatter plugin. The advantage of Forest pack lite is you can quickly work out how many proxies you need. Where with Peter Watjes scatter you have to take a stab at how many proxies you need. But the good thing about Peter Watjes scatter is you can scatter multiple grass proxies with different settings and materials, give them different weights and you get a more realistic random look.

 

TSuess. I clicked on the link and it did't work, i just ended up on the forums home page. Can you post it again.

 

Thanks

[TSuess]

Sorry guys. The link is:

http://www.renderededge.com/2011/05/dont-pass-on-grass.html

[TSuess]

I use Watje's Scatter plugin as well. But for manicured grass I've found it to be an unecessary step and that is beacuse I run the grass geometry as a seperate pass. It's a 10 minute render. I don't model grass beyond 40' from the camera. The tutorial goes in to some of the downsides of scattered proxies. With a 40' by 40' patch of short grass i use approximately 420,000 blades of grass. So I say save the proxies for the longer grasses/plants.

[dande]

Thanks Tom.

 

Excellent tutorial. Rendering out as a separate pass is a great idea. I'm doing a large animation at the moment with lots of grass. I was having trouble with my grass-o-matic grass being too heavy and I ended up using displacement with a falloff map. The separate pass would probably have solved my problem.

[TSuess]

You can also render out a top view to use as your texture map for grass beyond 40'. For your animation you can use a Z-depth pass as your 3d grass layer mask. This will help control the tranisition between the 3d grass and the grass texture map. I'm glad the tutorial helped. Spread the word. I really do think this is the best grass solution for manicured lawns and grasses. ANd the cool part is it's so frickin simple.

[beestee]

Thanks for sharing your technique! Definitely another tool for the toolbelt.

[TSuess]

For the record I would recommend throwing the Displacement Grass method out the window. It is unstable at best even on flat planes. Add topo and shapemerged sidewalk's and it takes on a mind of it's own. I'm sad about the hundreds of hours i'll never get back trying to make it work.

[beestee]

Results after a quick play through your tutorial:

 

[ATTACH=CONFIG]42976[/ATTACH]

 

I increased the width to 1/2" to fill a little better, and I went with a 100'x100' plane just to test out the extents of the tool. RAM would be the only factor limiting someone from utilizing this on a larger scale. With 8GB, my total limit of blades was approx. 700,000 between two Grass-O-Matic objects at 350,000 blades each. I had the visible setting down to 3% I think, this made the scene fast to edit with the higher number of blades.

Edited May 25, 2011 by beestee

[TSuess]

Looks good! I think alot of people wrote off Grass-O-matic a few years ago becasue of the limitations of single core CPU's. These days any decent PC could handle the render requirements. And when you run it as a seperate pass the FG calcs do not need to take into consideration the geometry of your entire scene. Another main point is that after a certain distance from the camera 3d grass becomes pointless. How long did the grass render take?

[beestee]

The render took about 15mins using Mental Ray, lit with an HDR enviro using importons and irradiance particles (instead of FG) at a resolution of 2400x800.

[Scott Dombrowski]

Here's a test I did.

 

[ATTACH=CONFIG]42983[/ATTACH]

 

(The building itself is under NDA and was hidden before I rendered). I used a combination of Grass-O-Matic and scattered proxies. I split my ground mesh into two parts... hopefully the screen shot helps explain it.

 

[ATTACH=CONFIG]42982[/ATTACH]

 

One part is a 12" wide strip along the edge of the curb until the curb is out of camera view (no sense in creating geometry that won't be visible, right?) This is the source for the Grass-o-matic blades. I think I set it to about 200,000 blades.

 

Then I made a 36" diameter Grass-O-Matic patch, turned it into an editable poly, scaled the middle blades up a bit to make it lumpy, then turned it into a mental ray proxy. I used Object Paint with random rotation and scale settings to paint the proxies over the rest of the ground plane. Forest Pro or Multiscatter would probably do a better/quicker job of this, but we don't own either of those yet and it only took a few minutes to paint the area I needed. And because I had the 12" buffer of Grass-O-Matic blades, I didn't have to worry about how the edge of the painted proxies looked.

 

Using this method I was able to get the "manicured" edges possible with Grass-o-matic with the fast area fill and variation possible with proxies. My next step is to work on the grass material to get some color variation in there.

 

Mental ray rendered this in about 4 minutes at 1280x720, FG on draft, AA at 1/16. I have a dual quad core Xeon 2.13GHz, 12GB RAM. Max Design 2012 on XP64.

Edited May 26, 2011 by nauticus27
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