Step 2 : Generating Displacement Map
First you must create a surface with UV coordinates as a target for your displacement map. You can do this by simply creating a plane and positioning it on top of your rings (Fig.04).

Fig. 04
Position so it just barely touches the rings, and assign mapping coordinates. With the plane you created selected, open the Render To Texture dialog box (Rendering > Render To Texture (press 0)) (Fig.05):
- Make sure you see the name of your plane here (shows name of selected object in Max).
- Click the Pick… button and select your rings. In the options menu here you can play around with the Min and Max Height settings to get a greater range in your displacement map.
- Choose Use Existing Channe” in the mapping coordinates menu, otherwise new ones will be auto generated.
- Assign a file name and destination. Choose tiff file format and make sure you select 16 bit texture to get best result. Then choose Displacement Map in the Target Map Slot.
- Set the Element Background color to black.
- Set the image resolution to 2048×2048 or higher (you might want to do a test render at a lower resolution first). Then click render.

Fig. 05
Note: The image you see rendering on screen is not the displacement map, but rather a default map 3ds Max puts up. You can disregard this map, or you can assign a nice metal shader to your rings and use this map for creating a diffuse map for you chainmail. To get the actual displacement map, find it at your File Name and Type location.
It can take some time to render depending on your resolution. When the render is complete, it should look something like this (Fig.06).

Fig. 06
Step 3 : Creating Material
Now that we have our displacement map, we need to create an Alpha map. I won't go into detail, but I simply modified the Brightness and Contrast settings in Photoshop to make the alpha from the displacement map. Alternatively you can generate one from the Render to Texture menu in Max.
And here's the Alpha map (Fig.07).

Fig. 07