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Grass Test using particle flow and MR


jinsley
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Thought I would post this up and see what people think...

 

Painted the texture and opacity map in photoshop quickly, used particle flow, a simple curved plane and mental ray to render. Took a little over an hour to render at 3000 px wide... might work really well to make 2 or 3 different types that aren't quite so chunky and distribute those... I only used 2200 mb of ram to render the image shown and this is a huge field, larger than anything I have done before without simply comping something in photoshop. I want to do a fly around eventually so I wouldn't mind keeping it all modelled in the scene...

 

what do you guys think?

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  • 2 weeks later...
  • 2 weeks later...
I've done a bunch of tests using the PF approach... one thing I found is that the RAM usage can grow exponentially when trying to create something dense. What I do nowadays is to scatter my geometric grass, use mesher so I can turn it into editable poly and then turn it into proxy.

 

 

I notice the same with particle flow... the thing I like about it though is that it is very easy to update, allows many options to dynamically control the geometry output. I have some courtyard renders coming up though and scattering geometry, attaching it all as a single object and trimming it to suit some walkways sounds like a good approach... with post up some more images when I get there.

 

Has anyone tried OnyxGrass??? I wonder if it is worth the purchase? I heard that it generates procedural textures that eat up virtually no RAM, but I don't know if I believe that.

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  • 1 month later...

okay. So Peter Guthrie makes me jealous. I love his grass and his foliage in general and I have been experimenting at home over the last day or so... I have been following his blog for a while now, but never really gave some of the techniques he applies to his grass and foliage.

 

He seems like a decent guy and shares alot of his findings on his personal blog:

 

http://www.peterguthrie.net/blog/

 

I would really recommend giving it a read, especially any VRay users out there.

 

here is my first attempt, just a simple box in an open clearing... it needs revision and a much longer look at the material, which I am finding dificult to translate over to mental ray without using SSS...

 

Info:

 

80,000 proxies @ 2000 polys each for the grass

 

500 proxies @ ~1.5 million polys each for the trees

 

FG map @ 750 px and final render @ 2250 px

 

Not sure about the time because my work computer decided to install updates and restart. Probably around 6 - 8 hours, it was sitting around 5 hours when I left to go get my kid.

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follow this, it's basically the same as what peter does but for mental ray, although its for leaves, similar applies to grass

 

http://3dsmaxrendering.blogspot.com/2008/06/translucent-leaves.html

 

Dave,

 

I followed this approach... the highlights and SSS look just don't seem to come through, I will look at it again, maybe I screwed something up... working on another material now that seems to have some better results...

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new material... getting a little closer. I think I need to re-model my grass blades and spend some time crawling around in the yard for better reference... or maybe just google.

 

I also know now that "grass" is alot more than just grass blades now... will model clover and other ground scrub that I can find to take some photos of and lok for a better base map. I think what partly makes Peters grass so nice is the variety of plant life.

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I used Particle FLow Technique to scatter in my previous works.

I enclose in the attachments. One render with grass and another detail image of ground with pebbles.

 

Here is a Making Of tutorial I have prepared, with the workflow how to bake particle flow into meshes and then proxy-scatter to save RAM.

I have rendered with Vray but the main pipeline would not change from MR to Vray as long as you are able to proxy.

 

http://www.evermotion.org/tutorials/show/7938/making_of_time_under_the_tree

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I used Particle FLow Technique to scatter in my previous works...

 

http://www.evermotion.org/tutorials/show/7938/making_of_time_under_the_tree

 

Thx for the link, I read that a long time ago... love those images you produced in that tutorial, they have great lighting and atmosphere... currently I am following Peter Guthrie on his blog and giving his technique a shot... seems to work very well...

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Threw this together yesterday based on a sketch I did a few years ago... I used a friends' architecture book for reference, but cannot remember the name of the building. If you recognize it, let me know.

 

Following the tips posted by Peter Guthrie in his blog.

 

Pretty happy with it, the long grass probably needs to be re-modelled...

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  • 2 months later...

I am working on a vegetation pipeline, you know the stuff - grass, trees etc etc. Im using Mental Ray and Max 2009. Im following Peters blog and also trying to translate in to mental ray. Scattering is fine but im trying to find a suitable work around the Vray2sided material without acually using SSS. So far i've not been very successful. I know this is possible i just can't seem to get it. I was wondering how you did it james?

 

Sorry to bring this to the forefront again. These vegetation threads never seem to go away eh.

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I am working on a vegetation pipeline, you know the stuff - grass, trees etc etc. Im using Mental Ray and Max 2009. Im following Peters blog and also trying to translate in to mental ray. Scattering is fine but im trying to find a suitable work around the Vray2sided material without acually using SSS. So far i've not been very successful. I know this is possible i just can't seem to get it. I was wondering how you did it james?

 

Sorry to bring this to the forefront again. These vegetation threads never seem to go away eh.

 

In Mentalray you can use the standard 3ds max Double Sided Material for front and back shaders.

 

I think what you are looking for is to use the Two-Sided(base) shader in your Arch&Design Tranlucency map slot to fake SSS. Your refraction, refraction glossiness and IOR should be 1.

 

First change the color parameter of the tranlucency slot to a light green or yellow green. As for your Two-Sided shader; make sure the color of the front parameter is black and the back parameter is white. You can drop your diffuse texture (leaf or grass) in the map slot of the back parameter. What this does is vary the intensity of the color in the tranlucency color parameter.

 

Reflection should be straight forward. I always check the Highlights+FG only slot as glossy reflections are really expensive.

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Also whats weird is that when i add a map (grayscale marbel procedural) to the back slot in the two sided shader it goes from fully translucent to semi transparent. The two sided slot is in the weight slot which i imagine is where it should be. Am i missing something totally obvious here.

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Thanks for that James, I put the two sided map in the wrong slot. Should have put it in the transparency slot to make sure it wasn't transparent. And that sentence right there kinda makes it obvious doesn't it! Im an idiot haha.

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  • 4 months later...

yes. I am still rendering grass 6 months later...

 

getting better all the time, I think I have the material down, now I am spending time having fun with geometry and creating different proxies to try out...

 

[ATTACH=CONFIG]37511[/ATTACH]

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That is gorgeous, I mean really nice mate. I have so many questions . . .

 

Thx Dave... that's a very nice comment to receive. Much appreciated. I get alot of heck in the office for always rendering fields and fields of grass and trees...

 

Ask away, if I can answer then I will or try to figure out the answer... I will say though that I did alot of colour and tone adjustment in PS.

 

[ATTACH=CONFIG]37512[/ATTACH]

 

I probably added far too much contrast as alot of the shadow in the trees is way too dark...

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No problem mate. Well for starters this screams 'making of' :)

 

Even the raw looks nice. So everything is 3d and then sky and colour adjustements in post?

 

Any inspirations for the final look? Reasons for the colour adjustments? Did you take the sky photo yourself? How many different patches of grass, long, short, patchy, clumpy etc? Methods of grass patch placement? Different render elements used? Daylight system or hdr?

 

The list doesn't stop there :)

 

Anyway 6 months have paid off, job well done

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