Using Vue 6 Esprit and the ecosystem module, I have created a terrain that is a mixed material comprised of a grass texture and a dirt texture.  I used a bitmap to make the dirt texture create a path through the grass texture.  When I try to plant trees on the grass part only using an ecosystem, some of them also land on the path that I am trying to keep them off of.  I have tried a number of techniques to avoid this happening, yet every time, at least a few trees land on the path (and not just at the edges, but sometimes in the middle as well).  Here is a list of methods I have tried already...

• using a bitmap in the variable density function (this is the technique that was suggested in a couple of tutorials that are geared towards vue 5 infinite)
• placing the ecosystem within the grass texture only
• laying down an ecosystem of rocks on the path and then trying to use affinity and repulsion to direct the trees away from them
• laying down an ecosystem of rocks on the path and then trying to use the decay near foreign objects to keep the trees away from them

Any help would be appreciated.  Thank you...

why not use the same bitmap you used to make the path as a function in the eco placement? Sorry, I am away from my Vue 6 at the moment.

The decay function would be the right choice here. Only catch: The object initializing the decay can not be included in the ecosystem...

If you dont want to remove the path from the ecosystem, then you can cover it with foreign (forgeign = not part of ecosystem) objects.

Set decay to like 5% (the correct setting depends on scaling of your plants/scene) and place cubes along the path. Assign an invisible material to the cubes (dont cast/receive shadows, transpareny 100%). Adjust decay values if necessary.

Thanks haegerst, that turned out really well although it takes a bit of time to lay down foreign objects all over the path.  Shortly after posting my original message, I actually came up with something else that has been working so far for anyone else who may have this problem.  Here is what I did...

I duplicated the path/grass terrain in the exact spot as the original and then went into the terrain editor.  From there I selected 'picture' and used an inverse (black/white color reversal) bitmap of the path image and selected 'subtract' to eliminate the path region of the terrain from the duplicate copy (note that the ground level of the original and duplicate terrains must already be clipped).  Then I set up my ecosystem and made sure it would only plant from altitudes -0.98 to 1.00 so it would not place anything where the terrain was eliminated since that area is at -1.00.  This kept all the objects off of my path and the only negative I can see to this technique would be if the extra terrain object consisted of a huge number of polygons that would lower the resources below an acceptable level.

Just jumping in, but when you use a bitmap to drive the ecosystem density, you also need to create a filter that is null from zero to around 0.75 ( by null, I mean a flat line), and from 0.75 to 1, a regular climbing line. THis normally does the trick.