I’ve been wondering for a while if it would be possible to have cycles render a grass material.
Where the surface would be flat, but as if it would contain gras
So something a bit better then just a green grass texture.
But less demanding as compared rendered strands of grass.
you could use alpha mapped planes representing clumps of grass such as is done in video games for trees and other foliage.
Or just model clumps of individual blades that are then rendered as instances (ie. where millions can be rendered using a minimal amount of memory).
It will look far more realistic than alpha mapped planes (especially up close).
Sorry perhaps i didnt explain it right.
What i mean is a material that can be aplied to a flat square, but more like a bump map / hair shaider kind of thing.
Some material that would look like if it was made of thousends of small short upward strokes… but its just a flat face. (upwards as real up) so depending on camera angle too.
shouldn’t be a problem to paint one or render one in blender, as long as your camera is fixed
yes that would be easy but the camera should move.
the grass verticles should be an effect (like some kind of noise) or so…
i often try strange setups its for fun but so far it seams not easy
Making displaced grass means you would need to have the mesh subdivided to the point where it would require more memory than strand primitives.
There’s probably a reason why the vast majority of CG artists don’t even try that approach.
Well it doesnt have to be an enourmes bump, part would be a texture generation of small vertical lines, a bit noise like.
I think a bit of it like a glossy material, where the glossy is between you material and lamp it reflects.
This is something like that, based upon camera look such texture should point upwards… its just a bit of a puzzle i think.
Even for small bumps, if you want the geometry to resemble thin vertical lines, then the mesh needs to be subdivided to where the polygons are smaller than pixels (and Cycles does not any form of adaptive subdivision or microdisplacement).
Though if you want to simply use a bumpmap of lines then it might be possible through the use of camera or window coordinates (but the texture will move across the surface if you want to do any animation).
for a very far away grass, you can use the velvet shader. it’s supposed to give a similar ligth distribution as grass (with variations in the inputs). Then a mix of plate particles and strands towards the camera… Depending on the distance from the camera, you may avoid particles or abuse them.