Hello @Anonymous,
I think you could bake a height map from this. It's going to require you to learn a bit about the Render to Texture utility in 3ds Max. There are some links here to get you familiar with the tool. Once you get the idea, instructions below.
Here's what I would do:
1) Attach all the parts into 1
2) Make a 4x4 plane that sits just under the lowest point of the high poly object from step 1
3) Use Render to Texture on the low poly plane. Use projection mapping and pick the high poly plane.
4) Adjust your cage so it is just over the highest part of your high poly plane. I usually hit "reset" then "push".
5) Bake the height map.
6) Go to the Projection options and set your Min and Max to just below and above the buffer values. (Buffer values only appear after you've baked once.)
7) Bake again, done.
Sample scene attached.
Best Regards,