What is happening here? Boolean modifier works *almost* So I want to hollow out a spheroid.
I redo the normals, extrude inwards, use p to separate the smaller spheroid copy, extrude its faces only outwards, move it into another layer, then use a boolean to subtract this from the original (big) spheroid. You see the result. It works almost.

Why not completely? What am I doing wrong? The smaller sphere's protrusions definitely go fully beyond the bigger sphere on both sides, inside and outside.

Here is the file for download: http://www.pasteall.org/blend/41696
You can do this with the new (blender 2.76+) intersect (boolean) feature.


Steps to recreate:


Go to edit mode (Tab).
Select all (A).
Extrude inwards (E).
Go to Face select mode (CtrlTab).
Extrude individual (Tools panel-->Add-->Extrude Individual) outwards.
Select entire inner mesh island (CtrlL).
Open dynamic spacebar menu (Space).
Type in "Intersect (Boolean)" and confirm.