« on: February 24, 2015, 09:08:13 AM »
Thanks for reporting. I found one crash bug, which I have fixed, but still there are problems in this particular example.
The holes are created with our Mesh Booleans, which are not perfect. The biggest issue is when the mesh has very different resolutions. So, in the screenshot, the hollow shell has much lower resolution than the outer shell. This causes the Boolean to fail. Although in future it will not crash, it will sometimes still produce the behavior where the hole is not actually added (this is what happens when the boolean fails w/o crashing). To get better results, turn up the resolution for the interior mesh (or reduce the exterior, although that still might not work because the hole cylinders are poking all the way through the object...)
For making holes manually, you might try the Add Tube tool. Use Linear mode, Normal or Y direction. Then you can position & boolean a cylinder in the same way.