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Le Grass

Posted: Fri Mar 05, 2010 8:58 am
by StompinTom
Hey hey,

Not much time now, but I'll explain later. Here is the BLEND file and a rendering of what the result looks like. Very simple, I made this in 2 seconds from scratch. No textures or nothing, just a very simple grass bunch object that I made with curves and a subdivided ground plane that I made wavy to show that it can be applied to any type of terrain. Materials are a simple brown diffuse material for the ground and a simple green Phong material for the grass. Extend this to forests, gravel, rocks, etc. etc. etc.

Feel free to ask for clarification. Hope this helps someone out... It's actually very light, I just did about 6 scenes each with several thousand trees and fields of grass and the packed Indigo files I made for rendering on my quad are all under 60 Mb with all the textures and everything. Not bad! Makes it very easy to swap around on a USB shtick.

Have at it!

EDIT: Extension '.blend' is not allowed. Hm.

You can grab the BLEND file from I think it's 4 Mb only because it seems to save the particle instances somewhere, though I'm not sure... Should be a LOT smaller otherwise.

Re: Le Grass

Posted: Fri Mar 05, 2010 10:28 am
by StompinTom

- Objects must be rotated 90 degrees in the Y axis for them to stand up straight on your grass. (RotY = 90)
- Over in the Extras panel you can set the size (1.00 means it is whatever size the actual instanced object is, you can play with that, though)
- Right below that is the field for changing the size randomly (very useful, I keep it between 0.3 and 0.6)
- In the Physics panel: Rotation is set to Normal, Randomize Phase is set to 1.0 (right next to Phase, NOT where it says Random right below Dynamic). This randomizes the rotation of the grass. It is this and the random rotation and placement that make it possible to make fields of grass that doesn't tile from a simple grass bunch model.
- Velocities are all at 0, don't need them.
- Make sure to enable the Emitter button so that it renders the ground plane, unless you're using a duplicated ground plane to control your particles, which may or may not be good practice.


Re: Le Grass

Posted: Fri Mar 05, 2010 11:53 am
by dakiru
Great stuff! Thanks for sharing :D
Will be very interesting to try this with density/size map 8)

Re: Le Grass

Posted: Fri Mar 05, 2010 12:18 pm
by StompinTom
Ah yes, forgot about that: Size and Density painting works fairly well, though it is useful to increase the resolution of your mesh so that you can get smoother gradients of change.

Re: Le Grass

Posted: Sun Mar 28, 2010 7:53 am
by Meelis

StompinTom i tested your grass-example.blend
Grass aint rendered, allsoo i cant see the grass in blender 2.49b.
And i modeled some grass blades added to particles system, i can see them but indigo wont render them.

Any ideas?

I convert to mesh then i can see, but if i use childrens are they instanced after converting to mesh.
5000 particles x 20 childrens is pretty slow, memory use is 4,5 GB for blender and keeps going up.
Blender shows total objects ~100 000, but cpu core is still under load. Can it be blender view is just refreshing objects in view and it's safe to save my work.

Converted to mesh preserves instancing and indigo uses very litle memory to render it.
But i guess it's blender bug, i can't go over 2000 particles and 15 childrens.

Re: Le Grass

Posted: Fri Jul 09, 2010 4:15 am
by kikeonline
How did you convert to mesh!!??

I tried alt-c and look for the convert button on the modifiers list and nothing :(

Re: Le Grass

Posted: Fri Jul 09, 2010 7:53 am
by StompinTom
It doesn't work with children and I don't use the actual particles or anything.

That scene should be set up so that it uses an object (grass patch or blade) as a particle visualization type. That's the whole beauty of it, you can sub in any object you want (for example, a tree model to make a dense forest).