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Author Topic: Saw-tooth grass edge  (Read 2781 times)

Richard Birket

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Saw-tooth grass edge
« on: November 25, 2010, 06:32:55 PM »
We are making increasing use of FP in our projects, and have recently been using it for lush lawns. Often, we have the following 'saw-tooth' edge problem with our grass, and wondered what you would suggest to best handle this kind of problem.

I attach a screengrab of a WIP render with shots of the 3 grass models we are using. They are randomly rotated.

Kind Regards,
Rich

www.blinkimage.com

yuv

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Re: Saw-tooth grass edge
« Reply #1 on: November 25, 2010, 06:49:18 PM »

This problem is produced by a very dense distribution, where the items are placed very close to the placement grid. Please try this changes:

  • Enable random tanslation, and set the X/Y randomness to 20% (Transform rollup).
  • Enable density and/or scale fallof at the edges of the spline (Area rollup)

This will reduce the grid effect and will add a smooth transition the grass and the pathway.

Daniel Quintero
Itoo Software
www.itoosoft.com
daniel@itoosoft.com

Richard Birket

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Re: Saw-tooth grass edge
« Reply #2 on: November 25, 2010, 07:16:59 PM »
Thanks for the reply.

I have applied the transform as suggested which removes the grid-like pattern, however, the scale falloff (and density falloff which I have also played with) don't really help me in this situation.

I assume this is just a limitation of the grass models I am using and the FP scattering approach.

It would be great if - somehow(!) - a future beta of FP would allow some kind of scattering approach that will keep cleaner edges for things like grass lawns.
Kind Regards,
Rich

www.blinkimage.com

iToo

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Re: Saw-tooth grass edge
« Reply #3 on: November 26, 2010, 10:08:41 PM »
I think the key is the size of the grass clump. It must be small enough to create a clean edge, but not too very small or the render time would increase significantly.

If that helps, i've attached a grass sample scene that creates acceptable edges and it renders pretty fast. I use a Forest object to create the grass clump, and other Forest to scatter it. Since both objects are parameteric, you may adjust the clamp radius and the density to get different results interactively.

This scene uses Max 2010, Forest Pro 3.3.6b and VRay 2.0.

PS: The Forest used for the grass clamp must use Display->Render Mode->Meshes, in order to be used as mesh source by other Forest object.

Carlos Quintero
iToo Software