Problem creating landscape with Displace

[syndra]

I have been tasked with the assignment of creating a desert landscape - along with the landscape, I need to model and include several outbuildings (including a bunker) and areas similiar to fox holes. I have created the texture map and displacement map to include an area where a bunker would be sunk into the land.

Usually this would be of no problem, however.....

I am currently using 3ds 7 (most of my experience is in 3ds 6) and I don't know if it is the program or something I am doing (or not doing), but when I create a landscape utilizing either a PLANE or BOX and add a DISPLACE MODIFIER along with a DISPLACEMENT MAP to the model, I get a gorgeous desert landscape, however I cannot see any of my other models unless I float them significantly above the landscape model.

In other words, the landscape model and the bunker and outbuilding models cannot be in contact with each other - when I render a frame to view the landscape, all I see is the desert landscape, but no buildings. If I raise the models far above the landscape, they render, however this is not what I need to create.

Can't have a bunker floating 20 feet above a desertscape!!!

I never had this problem with 3ds 6....

Is there something with 3ds 7 that I need to do (or not do?)??

[mrcotr145]

I'm currently trying to do some king of things like Rodrigo Gelmi done on is Tropical Forest as I uncounter some problems with the replicator setup and Heightmap geometry extraction.
As I understand Replicator can be done using the point source from a real mesh already displaced. I'm seardching a way to use my displaced Ground plane as a point source or if I can create point gloud on it using is own height value and a simple 8bit greyscale .png file in order to drive the density / distribution of the trees on this topography.