From Screen to Shop: Prepping a Rhino Model for CNC Cutting

The first time I brought a Rhino file into the CNC workflow, I thought it would be simple. Draw a shape, save it out, cut it on the router — easy, right? Except my “clean” model was full of tiny gaps, duplicate curves, and lines that didn’t sit flat on the construction plane. The CNC had no idea what I wanted, and the test cut was a mess.

That was my crash course in learning that the machine only cuts what you tell it to — not what you meant to draw.

Over the years, we’ve built a reliable process for taking Rhino models from digital concept to flawless physical parts. The prep work makes all the difference.

Here’s how we do it — step by step.

Step 1: Set Up Your File

Before you even think about cutting, get Rhino in order. Work in the Top view, set units to inches or millimeters, and name your layers clearly: Through_Cut, Pocket, Engrave. Think of layers as instructions for the CNC — if it’s organized for you, it’ll be organized for the machine when you start programing toolpaths.

Step 2: Flatten the Geometry

If you modeled in 3D, extract only what needs to be cut. Use ProjectToCPlane so everything sits perfectly at Z=0. The CNC doesn’t care about perspective views or floating geometry — it just wants flat, clean vectors.

Step 3: Clean the Curves

This is where most people stumble. Curves must be airtight. Delete duplicates, join segments into closed loops, and simplify any overly complex splines. If you can’t make a planar surface from it, the CNC can’t cut it.

Step 4: Think Like a Router Bit

This is the fun part. The CNC uses circular bits — which means inside corners will always be rounded. If your design needs a sharp inner corner (like a slot for joinery), add dogbones or fillet the mating piece. Designing for the tool is half the craft.

Step 5: Nest and Organize

Draw your stock rectangle (the sheet size you’ll cut from) and nest your parts inside it with proper spacing. Remember: wood grain direction matters, and plastics need breathing room so they don’t melt. Place the stock’s lower-left corner at (0,0) — that’s the CNC’s home base.

Step 6: Export for CAM

When everything looks right, export just the geometry and the stock outline. A simple DXF with lines and arcs is usually the safest bet. Leave dimensions, notes, and text behind — those only confuse the software.

Step 7: Add Context

When you send the file to us (or any shop), always include the details the machine can’t know:

• Material + thickness

• Tool preference (⅛", ¼", ½")

• Critical fits or tolerances

• Quantity + deadline

That’s the information that turns a drawing into a real, cut part.

Why It Matters

When files are prepared properly, CNC becomes magic. A façade panel drawn in Rhino can become plywood reality within hours. A professor’s sketch for a teaching model can turn into precise, repeatable components. And a designer’s logo can transform into signage strong enough to live outdoors for years.

At BDR DSG LAB, we’ve learned that CNC isn’t just about cutting — it’s about translating ideas faithfully. A good Rhino file is the bridge between your imagination and the machine.

👉 Got a Rhino model that’s ready (or almost ready) for cutting? Send it our way — we’ll review it, clean it up if needed, and help you get from screen to shop with confidence.