syntax for references to external equations??

Kind of new to solidworks and I've been designing an assembly that
consists of about a couple of dozen parts arranged into half a dozen
subassemblies. My experience has raised a couple problems that I can't
figure out.

1) A couple of the parts have features that drive many of the
remaining parts' shapes and it seems reasonable to use an equation or
a design table to put these dimensions in one place for all the parts
to reference as needed.

Is there a way in an assembly to reference an item in the equations of
one of the *other* parts??

Say Part1 has an equation "od"=42.0, I have tried creating an equation
in the assembly and I've tried things like: "D1@Sketch1"="od@Part1"
and various other syntaxes but I just can't make it work. It seems
that equations are only local, that is, you cannot reference equations
that are not in the equations of the current part.

SolidWorks "Help" talks about global variables, but I'm a computer
scientist and these don't look "global" at all, just static variables,
i.e. something you set and which isn't driven by a reference to a
dimension or other object. Needless to say that difference in
connotation has made me spend quite a few hours trying to "force" them
to act globally.

2) Why can't I have relative paths in external references? What a
pain, I can't move files to a different parent directory even if I
keep the SolidWorks "subtree" the same? Makes reorganization of
filesystems a tragedy. Just plain dumb.

Thanks!

 

I believe that when two parts are in an assembly you can reference the
dimensions of one in the other in the usual way. Perhaps I am just
thinking of this from part to assembly.

There are examples of driving dimensions from excel or access in the
API help and I think on the SW subscription site.

TOP

 

Yes but you can only reference dimensions. You cannot reference
equations or design table elements. At least not that I can figure
out.)

What I want is to create an equation table in a part that has an
outside
diameter that I can vary. This OD winds up driving the sizes of about
six other parts in the assembly. I've got some circles that I want to
be
smaller than this OD, like "ID"="OD"-.01.

Great, let's do that with dimension references... First you need to
create an assembly that includes the OD part. (Which you might not
actually want to do because this might be part of a subassembly that
gets assembled prior to mating with the OD part but as you can see
it's dimensions are still dependent on the OD part.) Anyways,
Create a circle in the other part. now constrain it concentric. Now
constrain it .01 smaller than OD... Oh wait... you can't; no such
constraint is possible. OK let's create another concentric AND equal
construction circle but lets create a dimension between this circle
and
our desired circle and set that to .01. Fantastic... Problem is there
are
two solutions. One circle that is smaller by .01 the way we want...
and
one that's bigger. So you resize your part and then everything goes to
hell because the part can't rebuild because SW prefers the closer or
less convenient solution or your wonderful interference fit just
became
a loose, sloppy fit.

The best solution would be to be able to say "D1@Sketch1" =
"OD@Sketch4@Part1" +0.001 which you can do however there are
a few variables that drive so many parts and assemblies that it
doesn't make sense to force them to be included as components.
And it would be better to say "D1@Sketch1" = "OD@Global".

For instance, I'm press-fitting a bunch of delrin parts into stainless
parts, Let's say I know that my press-fit is .0015 per inch of
diameter
over but I might want to change this value if I change to aluminum
or polycarbonate for instance. Right now I have to create a
phantom "part" with a .0015 dimensioned circle in it AND the
crappy thing is I have to include this "part" into an assembly with
the desired part so that the desired part can reference the
phantom part. Just plain stupid. There should be a "Project"
and you should be allowed to have variables, or equations, set
in the Project that any part or assembly can reference without
phantom parts or such silliness. There is a need for abstract
values or "dimensions" that are not associated with a part, an
assembly or the inclusion of such yet still affect all the components
of your model. (Coatings are another I can think of, are you going
to chrome all those pieces? that changes the fit of everything.)

I'd even be ok with a lack of project concept and just have one
giant super equation table that EVERY part in SW has the same
access to the same variables. Even if one part is from a missle
while another designed for a milking machine. But then again
I don't have a lot of projects.