Itoo Software Forum

Author Topic: Different grass patch for the edge mode  (Read 682 times)

QL2487

  • Newbie
  • *
  • Posts: 10
Different grass patch for the edge mode
« on: February 24, 2016, 02:27:39 PM »
Hello,

I'm not sure that this feature is already implemented in the algorithms but here is my suggestion. We are all usually using patches of grass for a lawn and edge mode with density and scale curve for adapting grass for the edge. Is there a solution that for the main (central) areas of the surface use the larger group patch and for the edges to be able to use smaller patches or individual grass leaves? Does this make sense?

Cheers,
Boris

Paul Roberts

  • iToo Software
  • Hero Member
  • *****
  • Posts: 1593
Re: Different grass patch for the edge mode
« Reply #1 on: February 24, 2016, 02:53:46 PM »
Hi Boris,

If you're using V-Ray, Corona, or Mental ray you can use the new Edge mode to clip large patches on the borders. It's the easiest way to set up a lawn with clean edges and you can see a tutorial about it here: http://www.itoosoft.com/tutorials/tutorial_edge_mode.php

This feature was introduced for V-Ray in Forest Pack 4.3.3, and is in the current beta for Corona and Mental Ray. If you are using any other renderer you can use the techniques demonstrated in the Grass Edges tutorial to scatter large patches in the centre of the area and small patches or individual blades around the perimeter.

I hope that helps, please let me know if you have any further questions.

Many thanks,

Paul
Paul Roberts
iToo Software

QL2487

  • Newbie
  • *
  • Posts: 10
Re: Different grass patch for the edge mode
« Reply #2 on: February 24, 2016, 03:21:31 PM »
Hello,

thank you for the fast reply. I'm aware of the edge mode, but is this the same as the trick with demonstrated in Grass Edges tutorial? Does the edge mode "know" where to use smaller patches and where larger?

Cheers,
Boris

Paul Roberts

  • iToo Software
  • Hero Member
  • *****
  • Posts: 1593
Re: Different grass patch for the edge mode
« Reply #3 on: February 24, 2016, 04:42:46 PM »
Hi Boris,

No it's different. With edge mode there's no need to use smaller patches because we remove geometry outside of the spline at render time. The advantage is that you can use the same size patch for the whole area and still get nice clean edges. Actually it works by using the lowest Z Vertex of each of the item's individual elements to check if outside the scatter area. If true only the individual element is removed creating a clean edge, without slicing the geometry. Note that when using edge mode, an element is defined as a group of connected faces that share the same material ID, these are the same elements used by Forest Color.

With Forest Pack 5 which is currently in beta but out soon, if you want to combine Edge mode with the ability to swap segment's based on their distance from an edge you could use an Effect. In the following example I'm still using patches, one that's densely populated for the inside area and one that sparsely populated for edges.



Then, using the Edge Effect which I've attached to this post I can place the sparsely populated patches only at the edges. It uses the first item in the geometry list for the main areas and the second item for the edges. There's a single parameter to set the falloff distance. For more information on how to install effects in Forest Pack 5, check out the documentation here.



This gives you grass that dies away as it reaches the edge instead of stopping immediately. This combination gives you the best of both worlds, efficient scattering of large patches plus the ability to swap segments at the edges.



I hope that helps, please let me know if there's anything else I can help with.

Many thanks!

Paul

« Last Edit: February 24, 2016, 04:44:22 PM by Paul Roberts »
Paul Roberts
iToo Software

QL2487

  • Newbie
  • *
  • Posts: 10
Re: Different grass patch for the edge mode
« Reply #4 on: February 25, 2016, 08:44:08 AM »
Hello Paul,

You're the best support in the world :)

Thanks a lot for your time and great explanations

Cheers,
Boris