#1 Introduction to 3D modeling for 3D printing with Rhinoceros No.1

Before you think about 3D modeling in your PC, it'd really good for you to consider about how you create 3D objects with physical materials. Ceramic has a number of different modeling techniques such.

Sources from http://www.lakesidepottery.com/

Thus it's good to keep in your mind that different 3D modeling softwares and their commands offer different methods to create 3D objects in the virtual spaces.

Polygon based 3D modeling VS NURBS curves

3D modeling a cup by NURBS in rhino and Polygon in Maya (Rhino generates a surface from NURBS curve and Maya subtract the inner volume). * source for Maya tutorial from Next Animation

One thing you need to remember about Rhino is it's NURBS modeling software that is different from Polygon based softwares. Although it can generate polygons but there are by far fewer ways to edit if you model Polygon in Rhinoceros.

 

Let's get started! 

This tutorial teaches you how to create an iPhone6 case. 

1. Sketching (Line, Rectangular, Measurement etc)

An important preparation to 3Dmodel a case for an object, it's always good to make the actual shape. Here, I 3D model iPhone 6s first.

Let's draw a line. Line command in Rhino is grouped in 'Curve'. There are a number of different kinds of lines in the group but don't be panicked when you see the many options in the group CURVE. You can select 'Rectangle' from the tab, type in the command window, or click the icon like the images below.

Drop-down menu for Curve

Drop-down menu for Curve

Tool palette for Curve

When you select the icon 'Rounded Rectangle' (or you can either type 'rectangle' in the command window and press the 'rounded' button'), it will ask you three values.

  1. First corner of the rectangle - Type the number there '0,0' and hit the enter key. It placse the object corner to the grid's 0,0 position.
  2. Other corner or the length - Type '6.7' (unit cm) 
  3. Width - Type ' 13.8'(unit cm)
  4. Radius or point for rounded corner to pass through - Type '0.3'

It's always good to write the measurement for what you designed. Go to Dimention in the Drop-down window and select 'Liner Dimention' tool. Assign the first and the second points of what you measure like below.

2. Creating a surface from a curve

Prior to this, I recommend to duplicate the curve you created in order to allow you to see the process and go back to where you want whenever you want to come back to the past process.

 Select the curve and command 'Surface from planar curves' like the image below.

planar_surface

Now you have a surface that is open and 2 dimensional. 

3. Make the surface 3D dimensional

Type the command 'Extrude Srf'.

IPhone6 has the rounded corner so let's model the detail, quickly!

Type 'Fillet edges' in the command window. It asks you to assign the edge first. Select the edges like below.  Every time you select the edge, assign the next radius value 0.35 (unit cm) so that you can have nice smooth arch like below.

You've now created a quick iPhone6 3Dmodel!

Now, I am going to design the iPhone case like this.

4. Creating the pattern

There are many ways to design an iPhone case, but here, I would like to start making the pattern. I copy the outline of the iPhone6s' first and then calculate the grid for the pattern. 

creating a grid to make the pattern

creating a grid to make the pattern

Now, I am going to create an interwoven surface that I am inspired by Erin Hauer manually as this is for beginners. Grasshopper skill is NOT required! Here, I'll create the triangular pattern in that I have not seen many like that. I promise, once you create it, you can see the geometry more when you see similar kinds.

Let's draw a rough sketch of the pattern. You can always modify it and come up with different ways to make it! I have done probably four or five different ways to make this same geometry. 

  1. Use command 'Explode' to take the square into lines *image left

  2. Draw a diagonal line with Line Command 
  3. Type 'Divide' to divide a line into four pieces equally
  4. Draw a line for the HALF triangle *image second left
  5. Draw an arch with 'Control Point Curve' command and click three points, first end, the mid point of the diagonal line, and the last end (when you turn on the points by a command 'PointsOn',  you can see the control points on the center of the triangle)  
  6. Use 'Offset' command and give 1mm thickness *image second right
  7. Use 'Extend' to extend the line to the square edge and remove one of the one of them by 'RemoveControlPoint' (click the line and one knot one of the mid one)
  8. Adjust the geometry as you like by moving the control point (I didn't like the shape so I made a bit of change)
  9. Mirror the arch and split the arch lines by the lines of the square grid with the 'Mirror' and 'Split' commands

Feel free to make the lines by free hand drawing! Yet, remember that keeping the control points are only three for the arches.

Let's make the lines three dimensional and a surface.

Use the command, 'EditPointsOn' and grab three points in 'Front window' and move them 2mm by pressing 'shift' key in order to move the points streight up.

As we've already done, draw a line and one more arch from the center of the arch to the corner like the image below (you can raise the height a little bit higher than the other arch)

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