I have a MiniMap camera floating above my scene, and I want it to render my terrains without rendering the vegetation on them.

I have a script attached to the camera, the relevant parts of which are included below.

The script sets the terrain's terrainTreeDistance and terrainDetailDistance to 0 before the camera renders, and after the camera renders, it resets the terrain to it's previous state.

Interestingly enough, the minimap camera renders trees on the terrain even with this script present. I know the script is properly changing the terrain vars, because if I remove the OnPostRender() section of the script, the trees disappear.

It looks like the terrain object defers the application of my settings 'till after the camera has rendered, by which time it is too late to do any good. Could this be possible, and if not - what else could I be doing wrong?

Ryan Scott suggested that I use shader replacement to hide the trees - and I may end up needing to - but I would much rather save the terrain object all the work of feeding the trees to the graphics pipeline to begin with.

function OnPreRender () {
    revertFogState = RenderSettings.fog;
    RenderSettings.fog = false;

    if(World.terrains) {
    	if(World.terrains[0].lighting == TerrainLighting.Pixel) terrainLighting = true;
    	else terrainLighting = false;
    	terrainLOD = World.terrains[0].heightmapMaximumLOD;
    	terrainTreeDistance = World.terrains[0].treeDistance;
    	terrainDetailDistance = World.terrains[0].detailObjectDistance;
    	for (var trn : Terrain in World.terrains) {
    		if(Game.Settings.renderLevel > 4) trn.heightmapMaximumLOD = 3;
    		else if(Game.Settings.renderLevel > 3) trn.heightmapMaximumLOD = 4;
    		else trn.heightmapMaximumLOD = 5;
    		trn.lighting = TerrainLighting.Lightmap;
    		trn.treeDistance = 0;
    		trn.detailObjectDistance = 0;
    	}
    }
}

function OnPostRender () {
    RenderSettings.fog = revertFogState;

    if(World.terrains) for (var trn : Terrain in World.terrains) {
    	trn.lighting = (terrainLighting ? TerrainLighting.Pixel : TerrainLighting.Lightmap);
    	trn.treeDistance = terrainTreeDistance;
    	trn.detailObjectDistance = terrainDetailDistance;
    	trn.heightmapMaximumLOD = terrainLOD;
    }
}