Your partner can create the heightmap in 3dsmax too. It is a pretty easy process: A plane below the landscape. The 'Projection' modifier applied to it with the landscape as 'reference geometry' and the projection 'Cage' tall enough. Open the 'Render to Texture' tool. Enable the 'Projection Mapping' and add the 'HeighMap' element as output. Select the desired bitmap resolution and render.

Salud!