3D grass shader to mimic large grass field

[Zhi]

Hi all,

I am new to Vizard. I used Virtools previously. There are some sample compositions in the Virtools forum, using shader to create mimic grass field effect. Some 3d model software, such as the 3ds max, also support online rendering of grass/fur effect. I am curious whether anyone has used shader in Vizard to mimic large field of grass land. Is there any link or script that we can share on this topic?

Thank you.
Zhi

[Zhi]

Never mind. I found a way to use 2D texture to create a wonderul large grass land effect.

Close the thread.
Zhi

[JvdBosch]

Originally Posted by Zhi

Never mind. I found a way to use 2D texture to create a wonderul large grass land effect.

Please share this with the rest of us. Did you use the shell technique?

[Zhi]

I do not use any shell technique. I simply found a very nice seamless grass texture (as attached) and applied it to the ground. To get rid of the regular pattern due to the repeated tiling of the grass patch (which gives a strong linear perspective cue). I 'blend' the detailed grass ground with a huge noise texture surface. The visual effect of such a grass field looks pretty good, even though it is still 2D textured. Here is the code:

grass = viz.addTexture('Grass.jpg') #Create the detailed grassland with about 100 m in diameter
for x in range(-51, 52, 2):
for z in range(-51, 52, 2):
if (x*x + z*z) < 52*52:
ground = viz.addTexQuad()
ground.setScale([2,2,1])
ground.setPosition([x, 0, z])
ground.setEuler([0, 90, 0])
ground.texture(grass) # Wrap texture on quad

BK = viz.addTexture('Noise.jpg') #Blend the detailed grassland with a low frequency noise map 100 m x 100 m
BKGrnd = viz.addTexQuad()
BKGrnd.setScale([100,100,1])
BKGrnd.setPosition([0, 0, 0])
BKGrnd.setEuler([0, 90, 0])
BKGrnd.texture(BK)
BKGrnd.zoffset(-1)
BKGrnd.alpha(0.2)

[JvdBosch]

You can also put the same texture in another map channel and repeat it on a larger scale, possible even rotated.

                    tex = node.getTexture(unit=0)
                    node.texture(tex,unit=1)
                    node.texblend(0.2,unit=1)
                    trans = viz.Transform()
                    trans.setScale([0.2,0.2,0.2])
                    trans.setAxisAngle(vizmat.EulerToAxisAngle(0,0,45))
                    node.texmat(trans,unit=1)

[Zhi]

Hi JvdBosch,

What does the trans.setScale([0.2,0.2,0.2]) do. Does it rescale the node or the texture map?

In my code, I have more than 2000 small ground patches (2m x 2m) with the same texture. I have another huge ground patch (100m x 100m) which has a different texture. My question is whether I can blend the two textures as if they were applied to the same node (i.e. the 100m x 100m patch), using the texblend function you suggest?