Introduction: Celtic Cross
Step 1: Background
What is Halloween with out a few ghouls, ghost, skeletons, and other creeping dead?
Yes, such things put the spooOOOOooky in Halloween!
And when you don't have a skeleton or zombie shambling around, a nice tombstone is a good reminder that one might be around the corner.
Let's build one!
Step 2: Creating the Base
We are going to create a Celtic cross tombstone. The original can be found in the Autodesk model library, but it cannot be edited in Tinkercad. This project will re-create this version in Tinkercad so you can customize for your own Halloween.
- Drag a box to the work plane and resize it to 20 mm deep, 20 mm wide and 7 mm tall.
- Drag another block to the workplane and resize it to 12 mm deep, 12 mm wide and 36 mm tall. Place the tall block on top of the short block.
- Drag a purple wedge to the workplane and rotate it so the right angle is to the top right. We are going to use this wedge to create the main vertical support shape for the cross (the bottom leg).
- Resize the wedge to 36 mm tall, 3 mm deep and 12 m wide. Turn the wedge into a hole and place it up against the right side of the tall block so that it will remove a sliver of the tall block. This will taper the tall block. Repeat this process all the way around the tall block on all four sides.
- Once there are slivers removed from all four sides, group all of these objects.
Step 3: Creating the First Arm
All of the arms of the cross are the same. We’re going to make the first one and then duplicate it for the others. This is a valuable technique for 3-D modeling: identifying which parts can be created once and duplicated.
- Drag a round roof shape to the work plane and rotate it so the flat part is facing up.
- Resize it to 5.5 mm wide, 10 mm deep and 3.8 mm tall.
- Duplicate this shape and rotate the duplicate 90° to the left so the flat part is vertical and on the left side.
- Resize to 3.8 mm wide, 10 mm deep and 2.25 tall. Position this object above and to the right of the flat part of the first round roof. This will make the slight flare at the bottom of the arm.
- Duplicate this object and rotate 90° around the y-axis. Move it to the other side of the top of the first round roof.
Step 4: Creating the First Arm Midsection
This step will create the tapering midsection for the first arm of the cross.
- Move a temporary workplace to the top of the very first roof shape you created. To do this, drag a workplane from the tool drawer and place it on the top of the flat part of your very first shape. Moving the plane here means that every new shape will appear on this plane and all measurements will be based on this plane.
- Drag a red box to the workplane and resize it to 8 mm wide, 8 mm tall and 10 mm deep.
- Drag a purple wedge to the workplane and rotate it so that the hypotenuse is on the left side and the right triangle corner is up to the top right.
- Resize it to be 9.5 mm tall, 1.75 mm wide and 10 mm deep. Place this wedge parallel to the top of the red box so that it will cut off a slim taper on the right side when it is turned into a hole. The bottom sharp point of the wedge should just touch the horizontal round roof. The top part of the wedge should be aligned with the top of the red box.
- Duplicate this wedge, rotate it 180° around the y-axis and move it to the other side of the red box.
- Group all of the shapes for the arm.
Step 5: Creating the Decorative Holes
This step will create the decorative spheres with the holes in the center and on each arm.
- Drag a sphere to the work plane and resize it to 3 mm in all dimensions.
- Drag a thin torus to the workplane and rotate it in two directions so that it is vertical and aligned to the x-axis. Resize it to 4 mm tall, 4 m wide and .5 mm deep.
- Use the Align function to align the torus and the sphere to the midpoint on all three dimensions.
- Select both shapes and duplicate.
- With both shapes selected, move the shapes up and embed into the midpoint of the bottom part of your new arm.
- Make a duplicate and move it to the opposite side of the arm.
- You can use the Align function to align to the midpoint of the arm.
Step 6: Duplicate and Rotate the Arms
This step will create the other three arms and the circular cutouts between them. It helps to do these in pairs so that they are symmetrical.
- First, create a duplicate of the bottom arm and rotate around the z-axis (turn it upside down but still facing you.) Then move it straight up until there's 5 mm between the arms.
- Once it is in the right place, group these two arms and duplicate again.
- Then rotate again around the z-axis so that all 4 arms are exactly symmetrical.
Step 7: Completing the Cross
This step will fill in the center of the cross and cut the holes.
- Drag a box to the workplane and resize it to 5 mm tall, 5 mm wide and 10 mm deep.
- Select the vertical arms and group them.
- Select the horizontal arms and group them. Then align all three of these objects-both sets of arms and the new box to the midpoint of all three dimensions.
- Bring a cylinder to the work plane and rotate so the flat side is vertical. Resize to 2.5 mm tall and 2.5 mm wide. The depth does not matter. This is the hole we will use to cut circles between arms.
- Position the first cylinder between the left and upper arms. Once you have it situated, duplicate it and, using the arrow keys, slide the copy to the right.
- Once that hole is placed, duplicate both of the cylinders and drag them down to similar places on the bottom corners.
- Group all of the arms and the cylinders to cut the holes.
Step 8: Creating the Circle
This step creates the circle around the arms of the cross.
- Drag a cylinder to the workplane and rotate it so that the flat ends are parallel with the sides of the cross.
- Resize it to 22 mm tall, 22 mm wide and 6 mm deep.
- Select another cylinder and size it to 16 mm tall, 16 mm wide and 6 mm deep.
- Use the align function to align these two cylinders to the midpoint on all three dimensions.
- Turn the inner cylinder into a hole and then group the cylinders.
- Now we need to make a small indentation for the two rings on both sides of the flat part of the cylinder. Duplicate this large tube and resize it so that the outer tube is 21.5 mm tall and 21.5 mm wide and the inner tube is 20.5 hi and 20.5 wide. In other words, you’re making a ring that is 1 mm thick.
- Turn the inner cylinder into a hole and group these objects.
- Duplicate this object and change the measurements to 17.5 tall and 17.5 wide with the inner cylinder 16.5 tall and 16.5 wide. Group both of the small rings that you’ve made.
- Turn both of these objects into a hole and using the Align tool, align to the midpoints of the X and Y-axes and one edge of the z-axis. In other words, you want to just slightly embed these rings into your larger ring. Then duplicate the rings and push the copies through to the other side of the larger ring.
- Group all of these rings together and then use the Align tool to center the ring on the cross.
- Group all of these objects and then move the cross to the top of the base.
Step 9: Printing Your Celtic Cross
Because of the numerous overhangs, this shape needs supports to be printed in any position. Most 3-D printing software will calculate the needed supports and create them independently. As a user, you just have to indicate that you want supports.
In the next lesson you will learn to make an obelisk!
Next Lesson:Obelisk Tombstone