How do I model a 2.5D skull in Aspire?

Use File > Import > Import Bitmap / Vectors to bring in a skull outline (for example a DXF, EPS, AI or PDF file). Alternatively draw it with the vector drawing tools on the Drawing tab. You need at minimum:

• The outer skull shape
• Two eye socket shapes
• A nose cavity shape

All of these must be closed vectors.

Use File > New and set your material dimensions. For a 2.5D skull, material 1.5 to 2 inches thick gives enough depth for a dramatic relief. Keep the job just big enough for the skull so the 3D resolution is spread over the part (see the entry on Job Resolution).

Select your outer skull vector. On the Modeling tab, open the Round or Smooth Create Shape tool. Leave Base Height at 0, tick Scale, and enter a height of about 80 to 90 percent of the depth you want the carving to use. Click Apply. This creates the domed skull foundation. (Base Height adds a flat plane under the shape, so a large Base Height would give you a slab with only a small dome on top.)

Select each eye socket vector and open Create Shape again. Choose the Round, Smooth or Flat shape. For Flat, the Base Height is the height of the flat plane, which sets the socket depth. Set the Combine Mode to Subtract and click Apply. The sockets cut into the skull dome.

Repeat Step 4 with your nose cavity vector and Subtract. Use a shallower depth than the eye sockets for a natural look.

Click the Sculpting icon on the Modeling tab. If you have several components selected, the software prompts you to bake them into one component first, so save a copy of the file. Use:

• Smooth to blend harsh edges where shapes meet
• Deposit to build up the cheekbone areas
• Remove to deepen areas that need more definition

Press F3 for the 3D view (F2 is the 2D view). Adjust the individual component heights in the Component Tree if anything looks too flat or too aggressive.

On the Toolpaths tab:

• 3D Rough Toolpath: a 0.25 inch flat end mill is a common starting choice, with a stepover you test on scrap.
• 3D Finish Toolpath: a ball nose end mill with a reasonably small stepover. The documentation gives 8 to 12 percent of the tool diameter as typical, and a 0.125 inch ball nose is a common size for this kind of detail. Use the toolpath preview to check the finish quality, and use a smaller tool or stepover if the detail is not good enough.