Any Spline Areas
(closed / opened) define only the region for the distribution, but not the elevation. Adding such surface to the Forest object - Surface
- Add surface
should fix it. For these purposes the Areas
- Surface Area
should be turned OFF
. As described in our on-line reference guide:
"Surfaces are often used to define the scattered item's position on the Z axis in conjunction with splines and paint areas to define the region on the X and Y axes. Occasionally you may find that the full terrain is filled with items,even though there are spline areas in the Items List. If this is the case the usual problem is because the Area is on, when using surfaces with other Include areas it is important to turn the Surface off."
In case of scattering on complicated geometry there is also UV Surface mode
available under Surface tab using UV coordinates instead of XY standard ones.
"... is it possible to scatter a group with forest pack ..."
Groups are supported, but for a different feature: to create clusters of objects that must be scattered together (e.g. clumps of grass and flowers). In this case, each item is handled as an independent item. You can see an example of use in the Forest 4 demo reel
As mentioned in our on-line reference guide: "Do not use groups for objects that must be handled as a unique object (for example a tree and its leaves). In this case, attach all the individual parts into single mesh."
Actually, all objects which must be handled as an unique entity (as trees), all group objects have to be attached in a unique mesh.
"... when I scatter along lines I found that only by braking all the vertexes inside the lines the scatter starts to work properly ..."
Well, in case of open splines, the final result might depend also on the vertex type & the Interpolation of such shape object, but usually, there's no need to break vertices. Please feel free to share with us more detailed info regarding your troubles (a screen-shot would be ideal).