Your first terrain

1. Prepare the splines

Import or draw your contour lines. There is no need to close them, connect them or even out their points — the plugin takes the lines as they are.

Only one thing matters: each contour should sit at its own height. If your lines came in flat, move them up to their heights before building.

2. Create the object

Go to Create → Geometry → SplineGround, click the SplineGround button and drag in the viewport to place the object.

3. Add the splines

In the Modify panel, click Add Object under the Splines list and pick your contours. The order does not matter.

4. Build the terrain

Press Generate Surface. The terrain is built from what is in the scene right now: if you change the lines, press it again.

5. Fine-tune the result

• Iteration — how closely the plugin follows the bends of your splines. If smooth contours look angular on the terrain, raise it.
• Platforms — add platforms and roads here as Editable Mesh or Editable Poly objects. The plugin fits them into the terrain and builds the slopes; set their angle with Up Slope and Down Slope.
• Ground Works — add closed splines here for cutouts and zones. Hole cuts a hole, Region keeps the terrain only inside the outline, Split together with Hole turns the cut-out piece into a separate object, and Material ID gives the zone its own material number.

A trick worth knowing

Draw one spline around the whole site at the height you want the edge of the terrain to be, and add it to the Splines list.

Without that border, the plugin has nothing to rely on beyond the last contour, and the terrain may rise or dip unexpectedly near the edges. With it, every point of the terrain lies between known heights. It is the simplest way to noticeably improve the result, and it costs just one spline.

6. Done

The result is an ordinary 3ds Max mesh. Once you are happy with the terrain, collapse it, and from then on it behaves like any other editable mesh.