Complex Shapes via Splines, Intesections and Variable Rounds
 

 

In this tutorial you will create a ergonomically correct mouse using splines, intersecting extrusions and variable radius rounds. This tutorial assumes you already know how to extrude and make sketches.

 

Start by creating an initial sketch of the side of the mouse in the base workplane. (make sure your units are set to inches)

  1. Draw a 5" Line as the base (bottom) of the mouse and fix it in place.
  2. Draw a 1" line as the front of the mouse and fix it in place
  3. Draw a 0.25" line as the rear of the mouse
  4. Make a spline (as shown) from the front of the mouse to the rear.

 

The spline tool works by dragging n dropping points. The point will be splined (curve fit) as you drop them. You can always go back an move individual points by clicking and dragging them

 

You may have to try the spline a few times to get it to look like the above sketch

 

Extrude the sketch 2.5 inches. Call the extrusion, mouse side.

This looks a little like a mouse but to get the mouse to be move a a natural hand shape we will intersect this solid with a sketch on the bottom of the mouse

 

Start a new sketch on the bottom of the mouse

Call the new sketch, Bottom

This is where you will draw a top/bottom view of the mouse

 

 

Create the bottom sketch as shown. Its two splines connected via straight lines in the front and rear.

You spline shapes do not have to be exactly as shown. Use your imagination.

 

Extrude the bottom sketch

  • Call the extrusion bottom intersection
  • Intersect material
  • Distance, 2 or more inches. Just so it extrudes beyond the original object
  • Below workplane
  • Taper in -10 degrees
  • OK

 

 

The intersecting extrusion only keeps the solid that is formed by the intersection of the two solids. Study the created object to see what happened when the taper exceeded the side extrusion. Go back and change the taper. See what it does!

 

SET THE TAPER TO +5 BEFORE PROCEEDING

 

 

With the taper set to +5 its time to complete the mouse with 2 variable radius rounds

  • Select the right top edge of the mouse.
  • Click make round.
  • Select variable radius
  • round tangent edges
  • smooth variation

Enter the following values for the variable radius

  • At the rear 0%: .75
  • At 50%: 0.5"
  • At the front 100%: 0.25"

It is possible that your percentages might be reversed, 0% at the front, 100% at the rear

  • Click Okay

Make another variable radius round on the other side

  • variable radius
  • round tangent edges
  • smooth variation

Enter the following values for the variable radius

  • At the rear 0%: 1.0"
  • At 50%: 0.5"
  • At the front 100%: 1/8"

It is possible that your percentages might be reversed, 0% at the front, 100% at the rear

 

 

Add some constant variable rounds to the front and rear edges to complete the mouse body

Important lessons:

  • Making splines
  • The power of intersection extrusions
  • Variable Diameter Rounds

 

 

 

  
Tutorial By Steve Schweitzer, 2001