We are using Max 2009 x64 with a collection of vrayproxy bushes within an FP object. We have custom edited the trees so that we can control the positions, though they are randomly rotated. We also need them to follow a surface.
Creation was fine and without problem, and even using a surface caused no problems.
However, for some reason, the FP object now disappears unless the Custom Edit tree sub-object level is selected. We have removed the surface to see if this solves the problem, but it does not. The trees are only visible in the viewport if the tree sub-object is selected.