Ghost Clip

Summary

This 13x6x0.1cm paper clip makes organizing your papers more exciting than ever before! Make this friendly ghost your own by adding your initials and changing the color. I worked with Divya Khandelwal on this project, you can see her profile here: @divyakh2028_2915679.

Lesson Plan and Activity

This project aimed to create a ghost clip by measuring a reference clip and designing it in the Solidworks program. We had to work with a partner and do each step together so we ended up with identical designs and clips.

Construction Instructions

Construction Lines

1. Create a new part, click “Front Plane” on the left side of the screen, and click “Sketch”

2. To make a constraint box, create a center rectangle for construction centered on the origin with a height of 13 cm and a width of 6 cm. (Two midpoint lines will be created; we will call the vertical one line a)

3. Create a horizontal construction line slightly below (around 1 cm) the top of the rectangle, don’t use a specific measurement (this line will be called line b)

4. Create a horizontal construction line 1 cm above the bottom of the rectangle (this will be called line c)

Triangles

1. Make 6 triangles with two vertexes on line b and one vertex on the top line of the constraint box, making sure to start them at the left side of the constraint box and end at the right side so they look like a continuous chain. Don’t create line segments over line b.

2. Make the leftmost triangle side 1 cm

3. Hold the control key down and select the sides of the triangles (not including line b) and apply equal relations

Bottom Semicircles

1. Using the bottom line of the constraint box and line c, create 3 3-point arcs with 2 points on line c and one point on the base of the constraint box, making sure they are tangent to each other and the bottom side of the constraint box. 

2. Make the leftmost arc tangent to the left side of the constraint box, and make the rightmost arc tangent to the right side of the box.

Completing the Shape

1. Make a line segment from the bottom vertex of the leftmost triangle on the left side of the constraint box to the top of the leftmost arc on the same line.

2. Repeat on the right side.

Eyes

1. Create a circle with a center 1.7 cm away from the left side of the constraint box, 2.8 cm down from the top of the constraint box, and with a diameter of 1.2 cm.

2. Using the mirror entities tool, select the circle and mirror it over line a, creating an identical circle on the right side.

Smile

1. Create a circle with a diameter of 3.6 cm with a center at 4 cm above the bottom line of the rectangle and on line a. 

2. Make a vertical line segment with a lower endpoint of the diameter of the circle and a length of 4.4 cm.

3. Use the mirror entities tool to reflect the line segment created in step 2 over line a. 

4. Use the “trim to closest” feature to remove the part of the circle inside the lines and curves, leaving only the bottom half or a semicircle connected to the line segments. 

5. Use the offset entities tool and select both line segments and the semicircle, set the length to 0.6 cm, and make sure the yellow line is inside the other lines. Click “cap ends” to round the edges.

Design Choices

We created our original sketch by measuring a physical ghost clip and added relations and dimensions based on what we remembered from the Solidworks training we had done before. After we began to use the software, we changed some elements of our design for functionality or efficiency. The changes are listed by part of the design in the same order as the instructions.

Construction Lines

We originally made our construction line for the triangles 0.87 cm below the top of the constraint box, but we found when we did that the triangles were over-defined because we added other things like equal relations and a dimension. This means their position was already fully defined and it was not needed (more about the triangles in the “Triangles” section below). After we deleted the dimension for the construction line, the triangles were not over defined and we continued to modify our triangles without a specific measurement. 

Triangles

Our goal was to make 6 equal triangles, so at first, we added dimensions for the bottom side of one triangle and for the construction line, along with equal relations for the sides. However, we didn’t need to add that much, and the result was the triangles were over-defined. We tried to fix the problem by deleting the smart dimensions and instead using equal relations for all the sides so they would create equilateral triangles. 

It seemed to work until we realized that we had closed the triangles, so they were considered separate shapes rather than part of the whole ghost shape. We tried to delete the base of a triangle to see if that could allow the triangles to be part of the larger shape, but that didn’t work because we defined all the sides as equal before.

Before, we had drawn line segments over the construction line to make triangles, but to fix our problem we tried only adding line segments for the other two sides of the triangle. We then added equal relations for those sides. They were still not fully defined because only two sides had a length so we added a smart dimension for the leftmost side to be 1 cm, making all of the sides 1 cm. Because the base for the triangles was only a construction line, the shape was completely filled in, including the triangles.

This is our first version compared to the final.

Bottom Semicircles

Our original plan for the semicircles was to create three identical circles tangent to the bottom, sides, and each other with a diameter of 2 cm. We would then have used the “trim to closest” tool as we did for our smile to create semicircles. This would have worked, but we didn’t like the extra smart dimensions needed to define the circle. We found it was more efficient to make 3-point arcs instead, and by taking the same steps to make them tangent to the bottom, sides, and each other, they were fully defined without the smart dimensions for the circles.

Completing the Shape

To make a shape closed, the sides need to intersect with no gaps or overlaps, but we originally forgot to add vertical line segments from the bottom of the triangles to the top of the semicircles because of the construction lines on the sides. By adding this step, the shape was actually closed, which is important because otherwise it would not be filled in and it would not be able to extrude properly.

Eyes

Because the circles are symmetrical, we wanted to only make the circle on the left side and mirror it over the vertical construction line. Our measurements were all correct, but we measured the distance from the edge of the constraint box to the edge of the circle. In Solidworks, all of the measurements for circles are based off of the center, meaning we had to do some calculations. We added the length of the radius of the circle to our original measurement to get the distance, and we already knew the diameter of 1.2 cm, so we divided it by 2, giving us the equation 1.1+0.6=1.7 cm.

Smile

We forgot what the offset entities tool was used for, and we thought it was only for capping ends, so we ended up manually offsetting the smile by adding an extra circle and extra line segments. After we opened the offset entities tool, we understood its purpose and we deleted the inner circle and line segments. We found it much easier to offset the smile inwards 0.6 cm rather than manually doing that.

Final Comparison

The only problem with our ghost compared to the original ghost is that our smile went up higher than the original. 

We measured the top of the capped ends to the start of the semicircle, but we didn’t realize that by capping ends the height would be added on to the 4.4 cm we measured, making the ends of our smile higher than the original’s. This is shown in our original sketch compared to our final sketch, but we didn’t notice it because it was a very small difference.