Does anyone know how I can make a realistic grass field in the most recent way?
I learnt from tutorials with Houdini 13 but it seems a bit old and I'm still looking for tutorials.
I went this far but it is still hard to get it right.
What is the best way to make a realistic grass field in Houdini 16?
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- ALMINA
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- Doudini
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Maybe try the hair tools from houdini 16
If you want to build some system from scratch take a look at the khan academy pixar workshop where they show how they have done gras in brave. this technique can easily be applied in Houdini.
The main problem with your gras is that all of them look the same. try adding some randomness in heights and minor variations in the directions. in general having a more gras like shape can help too it just looks like a line atm. Take a look at these for example:
If you want to build some system from scratch take a look at the khan academy pixar workshop where they show how they have done gras in brave. this technique can easily be applied in Houdini.
The main problem with your gras is that all of them look the same. try adding some randomness in heights and minor variations in the directions. in general having a more gras like shape can help too it just looks like a line atm. Take a look at these for example:
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- ALMINA
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Hello, thank you for your reply 
I am trying to add random direction and random height to it but I'm having some trouble in the technical side…
Do you know how I can add random height and direction? I am trying to use the stamp from a copy to give it random amount but doesn't seem to work well.
I am trying to add random direction and random height to it but I'm having some trouble in the technical side…
Do you know how I can add random height and direction? I am trying to use the stamp from a copy to give it random amount but doesn't seem to work well.
Edited by ALMINA - Feb. 26, 2017 01:53:29
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- Doudini
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For stamping name a variable and put a value like: rand(@ptnum). kinda depends on what you want to do here.
Where you want to have that random value put: stamp(“../my_copy”, my_value, 0)
i personally would try to avoid stamp as much as possible as its really slow. You can use attribute randomize sop on the scattered points to add random values like scale, orientation and direction.
You can use these: (http://www.sidefx.com/ja/docs/houdini/copy/instanceattrs) [sidefx.com]
N (i use this for the direction so we use in Y a value from 0.8-1.2 or something)
pscale: will control your height so we put this like maybe 0.7 - 1.1
orient: the rotation. we can use something like -45 - 45
up: can be used for direction instead of N.
then you can also mix in more randomness with a point VOP and noises like turbulent noise to control color or drive further your shape.
I can post the hip file from the screenshot above later sometime if I dont forget. I jsut put that together real quick :3
Where you want to have that random value put: stamp(“../my_copy”, my_value, 0)
i personally would try to avoid stamp as much as possible as its really slow. You can use attribute randomize sop on the scattered points to add random values like scale, orientation and direction.
You can use these: (http://www.sidefx.com/ja/docs/houdini/copy/instanceattrs) [sidefx.com]
N (i use this for the direction so we use in Y a value from 0.8-1.2 or something)
pscale: will control your height so we put this like maybe 0.7 - 1.1
orient: the rotation. we can use something like -45 - 45
up: can be used for direction instead of N.
then you can also mix in more randomness with a point VOP and noises like turbulent noise to control color or drive further your shape.
I can post the hip file from the screenshot above later sometime if I dont forget. I jsut put that together real quick :3
Edited by Doudini - Feb. 26, 2017 02:18:13
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- ALMINA
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- ragupasta
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Well thought I would have a play with this. I made a point of not looking at Almina's node network and after completion mine looks very similar to yours. This is the copy stamp method, and for 10,000 blades of grass I think 10 seconds of stamping time is acceptable.
This is certainly not polished or anything and could be taken a lot further, but I gave myself a 30 minute window to play with.
NURBS curves rendered with the width attribute for Mantra. The attribute is controlled by a ramp parameter for customisation. Noise is added to the curves point position, colour is by a UV attribute on the curve itself, again using a ramp parameter.
Pretty basic stuff.
Was a fun little thing.
This is certainly not polished or anything and could be taken a lot further, but I gave myself a 30 minute window to play with.
NURBS curves rendered with the width attribute for Mantra. The attribute is controlled by a ramp parameter for customisation. Noise is added to the curves point position, colour is by a UV attribute on the curve itself, again using a ramp parameter.
Pretty basic stuff.
Was a fun little thing.
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- mawi
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- neil_math_comp
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Has anyone done tall grass, namely multi-blade grass? A few years back, (just for fun), I got part way through making a few assets for generating the geometry for grass of various types and levels of detail, including some ludicrously high-res hero grass, but I never got around to cleaning it up and making it usable, and I never finished getting the topology right for the connections between the blades on multi-blade grass.
If you're primarily interested in lawn grass, the next level of detail would be that there's a central fold in each blade, which could be faked by adjusting normals across the width of the blades in the shader if you're not zooming in very close. Lawn grass also usually has 2 blades coming from each plant, with a nearly-white base right around ground level, but I found that those are almost impossible to see in a real lawn from above. There are also tiny striations along the length of each blade, but they're pretty hard to see directly on lawn grass unless you're looking for them; they're much more obvious in tall grass. However, they do make shiny blades of lawn grass have very anisotropic shininess.
If you're primarily interested in lawn grass, the next level of detail would be that there's a central fold in each blade, which could be faked by adjusting normals across the width of the blades in the shader if you're not zooming in very close. Lawn grass also usually has 2 blades coming from each plant, with a nearly-white base right around ground level, but I found that those are almost impossible to see in a real lawn from above. There are also tiny striations along the length of each blade, but they're pretty hard to see directly on lawn grass unless you're looking for them; they're much more obvious in tall grass. However, they do make shiny blades of lawn grass have very anisotropic shininess.
Edited by neil_math_comp - March 4, 2017 22:49:38
Writing code for fun and profit since... 2005? Wow, I'm getting old.
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ndickson
Has anyone done tall grass, namely multi-blade grass? A few years back, (just for fun), I got part way through making a few assets for generating the geometry for grass of various types and levels of detail, including some ludicrously high-res hero grass, but I never got around to cleaning it up and making it usable, and I never finished getting the topology right for the connections between the blades on multi-blade grass.
If you're primarily interested in lawn grass, the next level of detail would be that there's a central fold in each blade, which could be faked by adjusting normals across the width of the blades in the shader if you're not zooming in very close. Lawn grass also usually has 2 blades coming from each plant, with a nearly-white base right around ground level, but I found that those are almost impossible to see in a real lawn from above. There are also tiny striations along the length of each blade, but they're pretty hard to see directly on lawn grass unless you're looking for them; they're much more obvious in tall grass. However, they do make shiny blades of lawn grass have very anisotropic shininess.
I've done tall grass/corn for features such as divergent and jupiter ascending, and it was based on a ‘transform pieces’ workflow, where all the blades/stalks/seeds/tassel are created at once, and then transformed by a point cloud. For distant plants, the leaves were represented as curves, and the seeds as particles. Now that for loops/compiled blocks/packed primitives exist, this could probably be done far more efficiently.
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- -heavy-
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sorry for hijacking this thread, but what would it take to make the grass dynamic - so if something drops on to it, it bends to the side…
?
?
Edited by -heavy- - March 9, 2017 06:39:23
Janko Kissel
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Maya & Houdini Smoke and Demolition VFX-Artist
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- matthias_k
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- -heavy-
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great, Matthias i check dat.
Janko Kissel
Maya & Houdini Smoke and Demolition VFX-Artist
http://vimeo.com/heavyatvimeo [vimeo.com]
https://www.youtube.com/user/masterheavyone/videos [youtube.com]
Maya & Houdini Smoke and Demolition VFX-Artist
http://vimeo.com/heavyatvimeo [vimeo.com]
https://www.youtube.com/user/masterheavyone/videos [youtube.com]
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