offsetting splines /sketch properties interogation

Hi
I'm having a problem with offsetting splines. I'm using a plane / surface
intersection to create a reference spline in one part (PART 1). In another
part (PART 2), I offset this spline first, then convert entities on the
original spline to create a sketch that can be extruded. The idea was that I
could change the surface profile if required and the internal framework
would follow suit.
When I modify the surface, the spline in part 1 updates no problem, but the
splines in part 2 lose the relationship (relationship marker is olive).
Delete the relationship between the surface/plane interface and the problem
goes away - the splines in part 2 follow any changes made in part 1, but of
course, the spline in part 1 is no longer driven by changes to the
surface.....
Any ideas on intersection curves and offsetting - the whole area seems a
little murky and solutions look like workarounds, rather than part of a
design philosophy by SW.
Does SW create a new spline when it updates intersection data, deleting the
original one? Hence why it looks like the intersection spline has updated,
but explains why the splines in part 2 haven't - they are tied to a spline
that no longer exists?

Is there any kind of way to see the property name of sketch elements (other
than using a design table to get the name). A design tree for the sketch
components would be nice, to make certain the splines in part 2 are still
referenced to the intersection in part 1.

Does anyone know of a simple volume calculator for SW? - Trying to work out
the approximate volume of several odd shaped tanks in the keel of a boat, a
simple "click on the bounding points of the volume" and calculate the volume
would be handy and faster than having to either carve a block to shape or
work out the X-section areas and do some maths.
Thanks
Deri
PS - many thanks to Dynabits for their spline measurement tool - incredibly
handy for doing bills of materials for stringers on yachts!

 

Deri,

You could try creating a part called water and fill the tank with it. This
will allow you to select the part and get volume, surface area, etc. plus
you can change the desity to reflect the tanks contents as required, plus
fill to the required percentage (usually 95% for maximum fill) to get an
accurate weight of your vessel in it's various trims.

Another advantage - you can slice sections off the top of the 'fluid' part
and determine the capacity at varous sounding depths.

Merry (an old Sea Dog)

 

Thanks Merry!
This is today's job (as well as creating a heap of assembly drawings for the
boat - Airfix have nothing on me!). I hadn't thought of the soundings
idea - this would be a neat extra to give the customer and having had one of
the guys spend ages figuring it out on another (non SW) boat we did, it
would go down well.
Thanks
Deri