Extrude - from?

I was at a workplace where they have SW2005 installed. I still have 2004
SP04, and I noticed an annoying difference: In SW2004, if you do a
boss-extrude and then offset from surface, the extrude starts at that
surface. I'm talking about a doubly curved surfaces here.
Now when I did that in SW2005, there was suddenly a tab "From", that
wasn't there before. I assumed that I had to set that to the surface I
was offsetting from, but that did not give the results I expected: the
sketch had some lines in it that were supposed to mark an area that
should nog extrude (I don't have a better way to explain this, think of
it as a 'hole' inside the sketch). The extrude didn't do this when I
used it in combination with "blind"! It did show holes in the preview,
but the result was a massive extrude (
When I used the "Offset from surface" option, it would either extrude to
the wrong direction (inside), or fail to extrude at all! Since the
surface was shelled, I could not extrude from the sketch and I had to
come up with tricky solutions.

Did anyone experience the same thing?

Ewout

 

SW2005 has a new capability to start an extrude from a surface and end
it on another surface. This means you can start a sketch on a separate
flat plane or face and then have the extrude start and end on a
non-flat surface or face.

You only want to use the from sub-dialog in the PM if you intend to
start your extrude from a face/plane/surface other than the one you are
sketching on.

The use of SW2005's PM for extrudes is not all that different from
SW2004. Just disregard the From sub-dialog unless you intend to use it
and fill in the normal extrude parameters just as you used to.