Create blood vessels

To make the eye model look more realistic, we will draw blood vessels inside the eye on the retina layer. This is only for graphics sake as the vessels cannot be used for any mechanical problems.

1. Read in combine all.com
2. Remove all structures except the retina and the optical nerve.
3. Create seperate egroup for arteries and veins. "gfx create egroup 'name'" "gfx draw group 'name'"
4. Select "Node Tool" in 3D graphics window. Check "create, streaming create, constrain to surface". coordinate field: coordinates. Put into group created in step 3 "name".
5. In Scene Editor, make sure "Default coordinate field" under "General Settings" is "coordinates", this allows you to see the nodal points as you create/draw them in the 3D window.
6. Now, you can start drawing the blood vessels in the 3D window, on the retina surface.

Once you've completed drawing the blood vessels, the nodal points can be used for fitting using the "snake" command. You have to create the segment.txt and fit.com file, similar to "fitting the zonules.":http://www.cmiss.org/cmgui/wiki/FitTheZonules

• This particular case is slightly different to fitting the zonules, we need to fix the two ends so the vessles won't move and remain connected, especially at the ends where the vessles splits or join to become one. This is done by adding weights onto the first and last nodal points in fit2.bob. Also, in the txt file, the first and last number of each segment must be the one that joins to the other segments otherwise the weights won't work properly.

<a href="fit2.bob">fit2.bob</a>