topic Re: Grass in Visualization

Grass

Anonymous — Thu, 11 May 2023 12:15:37 GMT

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)

Re: Grass

Dwight — Wed, 06 Feb 2008 06:25:35 GMT

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.

Re: Grass

Anonymous — Wed, 06 Feb 2008 07:46:50 GMT

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.

Re: Grass

Anonymous — Wed, 06 Feb 2008 17:11:28 GMT

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

Justin

Re: Grass

Anonymous — Wed, 06 Feb 2008 19:53:45 GMT

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?

Re: Grass

Anonymous — Wed, 06 Feb 2008 19:58:21 GMT

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

Re: Grass

Anonymous — Thu, 07 Feb 2008 03:08:36 GMT

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

Re: Grass

Dwight — Thu, 07 Feb 2008 03:24:45 GMT

can we please see what you did?

Re: Grass

Anonymous — Thu, 07 Feb 2008 07:30:32 GMT

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.

Re: Grass

Anonymous — Thu, 07 Feb 2008 08:15:27 GMT

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.

Re: Grass

Anonymous — Fri, 08 Feb 2008 01:23:56 GMT

I can't figure out the problem, so I'm going to scratch the drawing and start again.
The blue is the 'sky' colour that is normally generated on a rendering.

Re: Grass

Anonymous — Fri, 08 Feb 2008 08:55:14 GMT

Oh, sorry, my mistake, I read too fast so I got 1+1=3 in this thread.

A bad polygon could make this errormessage appear, but check your parameter in Settingswindows, or reload the objekt if you don't have make any bigger changes in the settings. Sometimes when you have a failure there it is a nightmare to find what was going wrong. Sometimes it almost feels like ArchiCad done something by its own.

Re: Grass

Anonymous — Tue, 12 Feb 2008 03:07:42 GMT

Dwight wrote:
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!

Yeah, Dwight's right. I tried rendering an exterior shot a while back using several different types of gdl grass patches...it prolonged the render time and even if you placed those patches on just the edges where the ground meets the model, you'll need patience and should be prepared for trail and error until you get what you want. It can get pretty time consuming.... but with some practice and some ready made templates from multiple trial and error renders...I could see how one could get away with this. Would even help If you had a powerful computer to begin with.