PART 2: MODELING THE SURFACE OF THE CORTEX

STEP 7

Making the folds. Using Adobe Illustrator I traced the wrinkles in each of the 6 views of the brain.

STEP 8

The thick yellow lines represent the wrinkles and the thin black lines represent a general midpoint between wrinkles. After drawing these lines I turned them into outline shapes so I could drill them onto the sides of the brain model. The small red and blue squares are the points that will make up the final brain mesh.
I saved the red dots, blue dots and lines as separate ceps files. I end up with 3 ceps files for each of the six view, giving me a total of 18 CEPS files to import into Modeler :(

STEP 9

I imported the line CEPS files into Modeler and extruded them so they intersected the brain shape.

STEP 10

I then used the Solid Drill command (on Modeler's Multiply tab) to Stencil a new surface on the brain shape.

STEP 11

I did the same with each of the 6 sides, and collect the resulting parts into a layer to serve as a background guide for drawing the wrinkles. This view shows the results of two of the 6 drill operations

STEP 12

I repeated this process with the red and blue boxes. Once I had the boxes drilled onto the surface, I cut them and pasted them in a new layer. I then use the merge points command with an absolute setting large enough to merge the little boxes into single points.

STEP 13

OK, now I am ready to start recreating the shape of the brain cortex. I have the points that will make a nice quad mesh in the foreground layer and the lines in the background layer to help me figure out how to connect them.

STEP 14

Selecting four points at a time, I worked my way along the wrinkles making quad polygons. I then did the same for the surface between the wrinkles. Building the whole brain this way took a lot of time to finish.

STEP 15

The shape of the cortex recreated as a quad poly cage.

STEP 16

Here I have hiden the outer surface of the brain and selected the wrinkle polygons.

STEP 17

I use the smooth shift command to extrude the wrinkles into the brain. Because I had the wrinkles selected I was able to give the polygons at the bottom of the wrinkles a different surface name.

STEP 18

The shape is now ready to become a smooth sub patch object.

STEP 19

Unfortunately this operation did not produce the ideal shaped cage for the wrinkles. The openings of the wrinkles were too wide. So, point by point, I worked my way along each wrinkle closing them up to get a nice tight seem. Here about half of the wrinkles are done.

The finished model does not look to pretty in polygon mode...

... but looks good as a subpatch object.

continued: PART 3