Grass

[Anonymous]

I have been looking through past posts and havn't been able to find anything. Can anyone give me advice on how to get good grass (lawn, just to clarify)

[Dwight]

How close do you need to get? How hairy does it need to be?

Grass IS difficult - evinced through the carpet tile-like texture we get with Archicad.

If you aren't looking too close, use a finely trimmed back-and-forth lawn cutting pattern like at your better lawn bowling clubs. This will address the inevitable pulsing.

If you really are obsessed with seeing individual grass blades, one of our more insane colleagues made a GDL object. Just try and render more than a putting green's worth before next Tuesday!

Archicad and LightWorks cannot do the spectacular grass effects you might expect like 3D Studio.

[Anonymous]

Grass in GDL is a "Computer is going down in 5..4..3..2..1.. *explode*" object. I've done a couple of tests, it look nice, but I really don't now if there is a computer that can handle it in ArchiCAD / GDL. 10 000 pieces of grassblades and your computer won't even let you rotate in 3d before cofféebreak. Then after a rotate, you have to take a cofféebreak again.
And 10 000 pieces of grass isn't much grass in real life...

What I did in an easy way :
Loop 10 000 times
x = random (a)
y = random (b)
z = random (100 mm)
ADD x, y, 0
BOX 5mm, 5mm, z
DEL
Repeat

If you want 'real' grass, export your model to 3d Studio or Cinema4d.

It would be nice with a grassshader though.

[Anonymous]

Or you can try Maxwell render and get these kinds of results with displacement.

Justin

[Anonymous]

Colyer-Lloyd wrote:
Or you can try Maxwell render and get these kinds of results with displacement.

Justin

Yup, grass shader is a kind of displacement shader.

This displacement in Maxwell render, is it a 'fake' shader or does it create 'real' 3d objects in render?

[Anonymous]

To use displacement for grass in Maxwell you need just your grass map and also a displacement map. The displacement map is just the light and dark areas to represent high and low spots in the map.

It is an actual 3-d object, but only in a render.

Justin

[Anonymous]

Thanks for your help.
I got a reasonable result using a modified capet, that will cut it. Ha ha ha.

[Dwight]

can we please see what you did?

[Anonymous]

Yes you can but I have completely lost my 3D image, just a blue colour. A warning 'says' Polygon has less than 3 vertices at line 202 in the 3D script of file Wallhole Cut.GSM.
I can't remember making any changes for this to happen.

[Anonymous]

Blue colour is a bumpmap but in normalmap mode, you can do a bumpmap in greyscale in photoshop, than use for example .dds plugin to photoshop and save as normalmap, then you got a correctdefined shadermap for a displacementshader that use normalmap. Differents between bump and normalmap is that bump only has vertical displacement and normalmap could have displacement that has angles.

But Colyer-Lloyd : So in render it builds 3d object? that's nice,
Often in shaders we only trix with lights/shadows and not actually change 3d model. But with todays fast computer, shaders that builds 3d object in render (or in gameworlds) are a reality. But all software doesn't support this yet.