My first project to learn Fusion 360. Got it right after 3 printings.

Print Settings

Printer Brand:

Creality

Printer:

No

Supports:

0.2

Infill:

Labists PLA ](http://www.amazon.com/s?url=search-alias&field-keywords=Labists+PLA&tag=thingiverse09-20) White

Notes:

Print as in STL file. No supports needed. Set z-seam alignment to Random if beauty is desired.

How I Designed This

I used calipers to measure the dimensions of a marker and cap. I modeled the marker in fusion 360 first, then used circles and extrude to model the cap. An exact duplicate of Crayola caps is difficult to 3d print, so I used only 45 degree angles to revolve a line into a cone shape inside the cap.

The snapping and locking is caused by tiny tabs inside the lid and they were difficult to get right since I could hardly measure them, and they are almost below the tolerance of a 3d printer. I had to experiment for this. They are 4 tiny ovals that stick out on the inside of the cap. They can be controlled by a parameter in the fusion file.

I noticed that you could put the cap on backwards and it would not lock into place, so I added a top platform to prevent this, that still allows you to put them onto the reverse end of the marker.