Signet Ring with Horse Mesh Model
Blender 3D Python Script

sample horse model by Endre Barath
http://etyekfilm.hu/horse_public_packed.blend (used with permission, thank you Endre!)
modified by Roy Goodell (scaled, rotated, and translated)


I spend most of my time trying to figure out how to use 3d models and not how to create them.
It's important to separate what I'm doing (creating a python script)
and the artistic talent required to make the horse 3d model.
They are different skills. I may be going overboard expressing this thought...
but just sit down and try creating a really good 3d model.

Signet Ring Script download - mnu_157a.py 7/31/09

mnu_157a_blend.zip with Horse Model by Endre Barath (modified by Roy Goodell)

Consider this a short tutorial on using mnu_157a.
The script is by no way complete or finished.
This is this the first draft explaining how to make *.nc files from Blender Mesh Objects.



When you unzip mnu_157a_blend.zip and load mnu_157a.blend into blender you should see something like this.
Right click the mouse in the text area, click on Execute Script to run the script.




Mnu_157a script menu:
Click on Signet Ring, Reset Defaults




Click on OK to Accept the defaults




This generates the signet ring and saves these files in the bpydata directory:

signet.dta

pos_x.nc

neg_x.nc

signet.nc




The rest of this page describes generating the horse mesh files.
First we are going to generate the bezel object.
Click on Draw Bezel/Depth.




Goto the front view (7 key).




We want to subtract the bezel object from the signet ring.
Shift right click on the signet ring.




Type W to bring up the Boolean Tools menu.
For some reason - the menu names do not seem to describe the menu commands.
I may have something wrong with my mesh models.
Click on Union (What should be clicking on is difference - but union works.... go figure.... ).




Now delete the bezel object and signet ring object
Right click on an object, X OK to Delete.



And you should see this.




Another view with solid shading.




ok - now we are going to make the mesh.nc file.
Select the horse mesh object (Right Click on the Horse).
(naturally you would want the horse object to be scaled, rotated, and translated to fit inside the signet bezel area)




One more thing.... We need lots of points for the mesh2nc() function to generate a smooth surface.
Currently I'm using a 0.05mm cutter with a 0.03mm stepover.
Set Subsurf, Levels to 5 (6 seems to crash on my computer).
(In the Modifiers/Subsurf menu)




Click on Mesh Object to NC.
ok to accept the defaults.
It takes about 15 seconds to generate the mesh.nc and mesh.doc files.




The mesh.nc file can be run on a cnc mill to cut the top horse design on the signet ring top.
If you want to preview what the nc file looks like (simulate the tool paths in blender).
Click on Simulate Mesh.doc.
I moved the horse and signet ring to layer 11 (M key).
So this view only slows the horse mesh.doc object.




You can zoom into this object and check if there are any errors or points you want to change.
Why is the point where it is? Don't know - really don't care, just want to fix it.
If you have lots of points like this you probably left the Subsurf Levels at 1, 2, 3, or 4.'




This view shows a point I want move.
Tab to go into the edit mode.
Sselect the low pt (right click on it).
g to move the point.
z to only move only in the z axis.
enter to accept the move.




Heres what it looks like after the point is moved.




zoom back out.

We now want to update the mesh.nc file.
The mesh2nc() function does not really require mesh data.
Mesh2nc() only processes vertex data.
So Click on mesh object to nc again (with the mesh.doc object active)
If you wanted to rescale the mesh object or make other changes that's ok too.




ok accepts the defaults.




To view the new modified nc file (simulation)
Click on Simulate mesh.doc




These are the files you should now have in the bpydata directory



Note: Mesh.doc can also be input into Mastercam, Rhino and other cad/cam programs.
(mesh.doc is an ascii text xyz point file, a format that is often used with digitizers)


If you have questions, comments, or know of better ways of doing these things please let me know.


I plan to do another video showing this ring being machined in wax.
Stay Tuned.


Roy Goodell 7/31/09 5xj@5xj.com