"Flatten Spline Z" is a MaxScript tool that flattens all the vertices (knots) of selected spline or line objects to Z = 0, effectively making them lie flat on the XY plane. It supports 3ds Max 2021 and newer by using the modern splineOps interface for compatibility.

Ideal for cleaning up imported shapes, preparing 2D outlines, or ensuring laser-cut-friendly flat geometry.

This script is completely free to use. If you'd like to support the author, you can purchase the extended license!

🛠️ How to Use "Flatten Spline Z" Script

✅ Method 1: Run Manually

1. Open 3ds Max (2021 or newer).

2. Select one or more Line or Spline objects in the scene.

3. Go to Scripting > New Script, paste the script, then press Ctrl+E or click "Evaluate All" to run it.

4. All selected shapes will be flattened to the XY plane (Z = 0).

5. 
   

✅ Method 2: Drag & Drop

1. Drag and drop the script file directly into the 3ds Max viewport.

2. The script will immediately run and flatten the Z values of all selected spline/line objects.