3D Model - Pallanguzhi/Mancala Game Board

Hi! My name is Manonmani Raffill and I am a sophmore at Los Altos High School. For this project I am modelling a Pallanguzhi board - a traditional Mancala style game from South India. Pallanguzhi is played using shells or other small tokens which each player moves around rounded indentations cut into the board. Although I did not model any "shells" to go with the board, you can play with any common household token (coins, beads, etc).

I learned more about the pattern tool when designing the game board. Although I have used patterns in sketches before, I was not very familiar with making patterns with faces or 3D features.

Computer running Fusion 360

Features/tools used:

sketch, extrude, rotate, fillet, pattern, mirror, revolute joint

Click "new design" in Fusion 360. Make sure the units are set to centimeters. To change the document units, click "document settings", then "change active units" and select from the drop-down menu.

Make a new sketch on the x-y (flat horizontal) plane, then draw a rectangle with dimensions 5 cm x 42 cm. Finish the sketch, then extrude 2 cm to make a rectangular prism.

This will be the main body for one half of the game board- all of the other features will be joined/cut out of this prism.

To make one of the rounded indentations for the shell pieces/tokens, first create a sketch on the top face of the rectangular prism. Sketch a circle, then use "sketch dimensions" to adjust the size and position.

• Diameter: 3.5 cm
• Distance from the shorter edge: 2.5 cm

Make sure it is centered vertically (halfway between the two longer edges).

Next, create an axis dividing the circle in half. This will be used as the axis of rotation. Make sure it goes through the center of the circle!

1. Click the "line" tool and select any point on the circle.
2. Click on the center of the circle.
3. Select a third point such that that the line has two = symbols showing that both segments have the same length.

Finish the sketch and use the revolve tool with the circle as the face, and the diameter line as the axis. It should automatically be set to cut the main body. You should end up with a single semi-sphere cut out of the prism.

Use the rectangular pattern tool to copy the semi-sphere cutout 7 times. Click the cutout face as the "object" and the x axis for "direction" (same direction as the long edge of the prism). The quantity (# of duplicates in the pattern) is 7 and the distance is 37 cm.

Click on the fillet tool. Select all of the edges on the FRONT and SIDE faces, there should be 5 edges total. Set the radius to 0.75 cm.

I would recommend not selecting any edges directly along the top and back faces, although this is optional. The design will still function in the same way. The only difference is that when the two halves of the game board are attached together, it looks cleaner overall if only the front and side edges are rounded.

Before duplicating the body directly, it is important to create an offset reflection plane in order to leave some space between the two sides for later steps. Click "offset plane", select the x-z axis. The offset distance can be any number, as long as the plane ends up past the main body.

Find the mirror tool in the drop-down under "create". Check that type is set to "Bodies", choose the main body as the object and the new offset plane for the mirror plane.

Each side of the game board has 3 sets of hinges which connect together.

The first step is to cut out a rounded/cylindrical section from each piece of the game board.

• Make a sketch on the right side of the body. Draw two concentric circles horizontally aligned with the top edge of one half of the board.
  • 0.4 cm diameter
  • 0.25 cm diameter
  • 0.02 cm from the vertical edge - this is to make sure there is a small amount of gap or tolerance between both parts of the board
• Repeat for the other half of the board except with an inner diameter of 0.3 cm instead of 0.25 cm, again to leave a gap/tolerance.Finish sketch and extrude. Select BOTH circles, making sure you have the ENTIRE circle (do not exclude any of the concentric rings). Set the distance type to offset. This will ensure that the hinge is not directly on the side of the board. Also, check under "objects to cut" that both bodies are chosen.

Next, extrude the outer ring of each circle for 1 cm in alternating intervals. The hinge on the left side will have peg attachments and the hinge on the right side will have a hole.

• On the left body extrude the outer circle twice:
  • Offset -2 cm, distance: -1 cm
  • Offset -4 cm, distance -1 cm

• On the right body, extrude the outer circle only once.
  • Offset: -3 cm, distance -1 cm
• On the left body extrude the inner circle through both existing cylinders, slightly more than the first set of extrusions. This will form a peg to fit into the hinge on the right side of the board.
  • Offset -2 cm, distance -1.1 cm
  • Offset -5 cm, distance 1.1 cm (for this one remember the distance is positive)

For all of the extrusions, check that the new part is being joined, not made into a new body. If the operation is automatically set to "new body", it likely means that the selected sketch doesn't connect to the main body. Either the sketch was made incorrectly, or some parts of the sketch were not selected when extruding.

Use a rectangular pattern to extend the hinges either 2 or 3 times. Make sure that the pattern tool is set to the type "features". After selecting all parts of the hinges on both sides of the board (there should be 6 total), choose a quantity for the number of hinges, and set the distance to -35 cm. The direction should be the x-axis, along the longest edge of the rectangular prism.

To be able to open the board more easily, add a tapered notch to the side. Create a sketch on the top face of the main body. At the very center of the front edge (opposite the hinge) draw a 3 cm x 0.125 cm rectangle. Repeat this for both sides of the board.

Finish the sketch and extrude both rectangles -1 cm. Add a taper angle of ~3 degrees to make the cutout slightly slanted.

Joining the two halves of the board is not necessary for 3D printing, but it can be used to show how the design will fit together/move before actually making the game board.

In order to join parts together, they need to be converted into components. Use the "new component" tool, making sure to choose "from bodies". Repeat this for both bodies.

To connect the two components, click on the "joint" tool. This requires one point of connection from each body. Hover over the cylinder on the right hinge and click the center point which appears. Then hover over the cutout in the middle of the left hinge, and again click on the center point. Set the joint type to "revolute" so that the hinges will rotate.

The components should align together and show a rotating animation.

Save and, if possible, print the game board! Unfortunately, I do not have access to a 3D printer at home, but I will try to print this out when I am at school again. It is likely too large to fit in most 3D printers, but it can easily be scaled down to a smaller size.

Once the board is printed, you are ready to start playing the game. Pallanguzhi is played with shells, seeds, or other tokens which players move between the rounded cutouts and collect, with the objective of having the most tokens at the end. Game rules can be found online!