crazy homeless guy

Anyone have experience rendering Hair and Fur as grass using MR? I have a lot of field grass I need to render around a building, and am considering this method though the first few initial tests fell flat on their face.

I was reading something on the LA user group site about specific MR hair shaders, but it sounded like it might currently be over my head.

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travis schmiesing

TheAllusionist

Haven't tried it since Max 9 so I am not sure if it will work with current versions, but you might try SuperGrass http://www.antiflash.net/supergrass/

And the all knowing mr guru Jeff Patton has an older tutorial http://jeffpatton.net/MR_Grass_displacement.htm

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Justin Hunt

I tried max hair and fur, it worked to a degree but just couldn't get it convincing enough. I was trying to create long, coastal grass. From what I remeamber you have to add a mr shader and set the hair to render as mr primitives, or something like that. Took ages to render though

Brian Bradley did a mentalboutmax video using hair in one of the project sceries (once again I'm going from memory) worked well
jhv

WAcky

Mr fur for grass is annoying. Unless its for long grass like justin mentioned just comp in real grass.

Like justin mentioned i would reccommend the Mental bout max tutorial in which they make grass using fur. They did a great job with it!

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James Burrell
Pixel Constructions

crazy homeless guy

Displacement is definitely not going to work. There is a couple of grass areas that range from 10" for one, and a foot and a half for the other. Right now I am working with a combination of proxies and comping in real grass in post to clean up the edges.

If I can get something like the second image on the linked site below, it might look quite nice. But I don't want to extreme render times. I am fine with it taking longer, but if it more than doubles the time required for the high res image, I am going to use something else. Right now I am at about 1-1.5 hours for a 4000x4000 wide image.

http://mentalraytips.blogspot.com/20...revisited.html

.

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travis schmiesing

crazy homeless guy

Another option I am considering is rendering the hair and fur in scanline, and then using that to comp onto the final image.

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travis schmiesing

peterguthrie

I would stick with proxies ;-)

The attached image was done using vrayproxies and the advanced painter script - I made 2 different 1m x 1m patches (which were made using standard max scatter and 3 grass blades) of grass and then painted them all over the terrain with random rotation and scale.

Attached Images

test10.jpg (139.3 KB, 88 views)

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Claudio Branch

Agreed.

I used this very approach recently and it worked great on my stills and animation.

crazy homeless guy

can i ask how you generated the grass model for the proxy? ...right now i am using modified plant leaves, generated with Onyx Flower.

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travis schmiesing

peterguthrie

I just drew a triangle to the size I wanted it in the left viewport, then added a edit mesh modifier so that it had faces and then a bend modifier. I then collapsed each one to an editable mesh and gave each one a different material ID. I made 4 like this all a bit different and then scattered them around a plane as per the attached image.

Its best to keep the grass as low poly as possible and with no thickness so that you can use a vray2sided material (not sure what the MR equivalent is) to simulate translucency.

If you want the grass to look like it is being blown by the wind you could limit the rotation to say +- 10 degrees and again when you paint them on using advanced painter.

Hope that helps,

Peter

Attached Images

grass.JPG (118.1 KB, 48 views)

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