I'm currently using Rhino5 and Grasshopper for making parametric designs for plywood furniture. The goal is to have the plywood cut by a CNC router. The software I've been using to create the g-code for the router is VCarve. Here's the process I've been using to get the 3D model from Rhino to a format that can be used within VCarve.
In the instructions below, I'm working on Windows 8.1. The Rhino version is 5 SR7 64-bit. The VCarve version is Pro 7.012.
What you'll be doing in Rhino is taking your 3D model and converting it to a 2D representation. Then exporting the 2D to the .dxf format for importing into VCarve. Here's the workflow.
Initial 3D Model in Rhino
In Rhino, you need to get all of your pieces from your 3D model layed out flat. I do this manually. I separate each component and lay them out. I rotate them as necessary to get them flat.
Flattened Model in Rhino
In the View pull-down menu, select Viewport Properties. In the dialog box, ensure that Projection is set to Parallel.
Viewport Properties in Rhino
Now, select all of the objects that you want to export. Then use the command Make2D on them. The screenshot shows the options to use for the commands.
Rhino 2D Drawing Options
Now, turn off the layers that the 3D model was on. Then you'll be left with your 2D model.
[singlepic id=30 w=500 h=350 float=center]
Next, select all of the 2D items that you want to export. From the File pull-down menu, select Export Selected. The Export dialog box will appear. Change Save as type to AutoCAD Drawing Exchange (*.dxf). Set your file destination and name. Then Save.
Your done with Rhino for now. Open VCarve. In the starting menu, select Open an existing file. Select the .dxf you just exported and click Open. Go ahead and set the Job Setup settings. Then save your file in the VCarve format by selecting Save As... from the File pull-down menu. Set your file location and name and click Save.
Saving VCarve File
Your model is now ready to manipulated within VCarve to prepare it for the CNC Router.