Since my last log entry, the project has gained mild internet fame. The best effect is that several people from around the world have added to the project. This log entry is about youtube user shy tavori's program that can be used to generate new cams from custom input paths.

Take a look at shy tavori's video explaining his program:

The program runs in 3D modeling program Rhinoceros. It uses an extension, Grasshopper, which adds block based scripting. I was not familiar with either application until shy tavori brought them to my attention. They seem like powerful applications.

I used his application to create a new set of cams- the heart shape. I made this choice because several commenters requested it and it is very recognizable. This has been the simplest shape I have created so far which has several advantages:

• The machine requires less hand power to run
  • Less intricate features give less opportunities for "valve float" which means less spring force required
• The outputted shape is larger
  • as measured by the projecting angle in degrees
• Higher total image resolution
  
  • The laser pen is moved farther. This is like printing a larger image with a constant DPI printer resulting in a higher total resolution.
  • My printer has an XY accuracy of ~0.2mm. The heart cams have a radius range (max-min) of 9mm. This kind of gives an approximate resolution of 45 X 45 pixels. This sounds bad until compared with the batman shape has an effective resolution of 17 X 17 pixels. Note that these are back of the napkin approximations and more complex math is needed for exact tolerance calculations.

Custom cams can also be created with my Go application. I think shy tavori's way would be easier for the average person.

Here is the procedure I used to use shy tavori's work to create the new cams:

1. Download/Install Rhinosourous
2. Download/Install Grasshopper
3. Download shy travori's grasshopper code https://www.dropbox.com/s/6n654qmxmp2vall/Custom Cams for MECHANICAL LAZER SHOW.gh?dl=0
4. Open Rhinosourous
5. Run command Grasshopper (opens grasshopper window)
6. From grasshopper window, open shy tavori's .gh file
7. Set correct laser radius (7.06)
8. Rhinosourous -> change to front view
9. Rhinosourous -> standard tools -> polyline
10. Draw target shape in pink circle
11. Grasshopper -> select far left item curve. Right click -> set one curve
12. Select the target shape you created
13. Grasshopper -> use slider to verify cams don't hit each other
    1. (you may have to disable the cam previews for this. To do so:
       1. select far right result -> right click -> preview)
14. Select far right result -> right click -> bake -> ok
15. Select newly created cams
16. Rhinosourous -> file -> export selected
17. Do the same for the other cam. (other far right object)

I manually added the heart emboss/deboss for identification. The resulting models can be found on my Thingiverse page.

Check out the result:

Turned out great. Thanks shy tavori!