Where is "list external refs" ?

[Pierrec]

Hello everybody, I have a small problem with SW 2008:

I have an assembly with all the parts that depend on each others. Each part has dimensions that depends on dimensions in other parts using strictly equations, such as "D1@sketch1" = "D2@sketch5@some_other_part.part". It's a bit tedious, but the way the parts are constructed is special enough that I can't use any other in-context mechanism to achieve my goal reliably.

Anyway, my assembly has 150 parts and is now complete and working good. Now I want to lock all external references in the parts, but surprise, I can't find the "list external refs" menu item when I right-click on the topmost entry in the FeatureManager. Can someone tell me what I might doing wrong here? or where I can find this feature?

Thanks everybody!

 

[Paul Zwaan]

My reply has 3 parts...


first of all I think you will be able to do what you want one component at a time by opening each component and right clicking at the top of the tree to find "list external references" etc... tedious I know, but I don't think you can do it any other way.


I also don't recall trying to break links caused by equations before. Perhaps there issomething you can do via the equations tab in the Feature menu? I have not tested this.


Regarding things you can try from the assembly itself...There are some external reference functions you can change for the assembly, but I doubt they are of much use because they are system related rather than document related here:


Right click assembly at top of tree, select "document properties" then "system options" then "external references"...

 

[Pierrec]

My reply has 3 parts...


first of all I think you will be able to do what you want one component at a time by opening each component and right clicking at the top of the tree to find "list external references" etc... tedious I know, but I don't think you can do it any other way.

Actually that's what I was trying/hoping to do. The problem is that, apparently, SW doesn't consider an equation referencing a dimension in another part file an external reference. Since none of my parts have anything but cross-part equations, the option to list external
references isn't there at all.

I also don't recall trying to break links caused by equations before. Perhaps there issomething you can do via the equations tab in the Feature menu? I have not tested this.

I'm more trying to "freeze" equation values that are evaluated from other parts. What happens is, my assy and its parts are complicated enough to require a PC with 8 gigs of ram, but my colleague who's supposed to do some post-processing on the parts I drew has a PC with "only" 4 gigs. So I was hoping to get him to work on the individual part files without the rest of the assembly, and be able to rebuild the part without getting a huge list of unresolved equations each time.

Regarding things you can try from the assembly itself...There are some external reference functions you can change for the assembly, but I doubt they are of much use because they are system related rather than document related here:

Right, I would like an option that's part-dependent. I did look around in the assembly options but didn't find anything useful.
Oh well, looks like I'm SOL with this.
Many thanks for your reply!

 

[Paul Zwaan]

I am not sure if this will help, but if you were starting again, I would advise to put as much of the geometry as possible into overview sketches in a dummy part and then link to that from all the other parts. This has some distinct advantages:


1. You can edit that overlay part on its own which takes very little system resources


2. It gives you a preview of what the assembly looks like before rebuilding... often this saves you time if it is not quite what you want first or second time(saves unwanted rebuilds)


3. It avoids nasty circular references... if you have ever struck this you know what I mean


4. You can break links to the dummy part easily


5. If you like using equations, confine them all to the dummy part if you can. This fences them off so to speak to overcome the problem you have now


6. I would probably use a design table with equations in it rather than the method you have used.And use Excel to edit the table. Again, this makes it easy to preview the equations and make sure they solve before rebuilding.


I still have a hunch there is some functionality inequations that you may not be using. A simple example is tosuppress the dimensions which areequation driven before handing over thepartto someone else. I needmore time to think of better suggestions(but I am pretty confident I could find some... just a bit too busy right now. how long have you got??)


P

 

[Pierrec]

The mechanisms I design with SW are a bit particular: almost all the parts depend on many others, often in subtle ways, and many parts are arranged in ways that are mechanically unsound or impossible, that just happen to work in real-life because steel is flexible and the guys who adjust them are good with files and hammers. I wish I could show you a screenshot of the sort of thing I design, but I'm under strict NDA. Believe me though, it's clockwork gone mad, enough so that I can crash SW in no time just by turning on half of the constraints between the parts and moving them a bit. Yet I have to come up with a model as close to the real thing as possible because precision of the machined parts are of the essence.

For example, one of the main part rotates inside another, and at 4 precise angles (defined in a sketch from various product requirements), other parts, pushed by various cams, must lock, eject and do other things. The shape of the cam that controls everything has to take into account the positions of all the parts at the 4 different configurations at the 4 angles of the main part, etc etc... In my assembly, it's not uncommon to have the shape of one part determined by a chain of positions of 5 or 6 other parts, themselves dependent on the geometries of other parts, that ultimately depend somehow on the geometry of the first part.

I have not found anything easier for that particular project than to redraw bits of parts inside another, set in certain positions, using dimensions that refer to the particular geometry of the refered parts with equations. By logically describing how individual parts interact with others this way, I was able to complete the model. I am aware of the danger of circular references and I took extra care not to introduce any. The result is however that almost all the sketches in all the parts have dimensions driven by other dimensions in other parts, because that's just how it must be.

Anyway, now I have a perfectly working set of 150 parts full of external references, only they are all concentrated in the "Equation" entry of each part instead of spread out across the entire tree. Solidworks knows there are external references in "Equations" because it appends a "->" sign on that line, and it knows the part itself depends on other parts as a result, because the topmost line also has a "->" sign, but somehow it refuses to treat cross-part equations as external references. I only get the option of listing them if I have at least one "true" in-context reference, in the traditional sense (i.e. editing inside the assy), and even then, it still refuses to list the equations as external references.

I've looked around all the options and I couldn't find anything. If you know of something, I'll be glad to hear about it of course. I'm not in any particular hurry however, I can get my colleague to work on other due-yesterday projects while I do the extra work on the complex part with my 8 gig machine, so if you don't have the time to take a peek, don't worry about it.

Thanks again for your advices!

 

[Paul Zwaan]

This thing about SolidWorks not allowing you to break references made through equations sounds like something SolidWorks should be made aware of.


I suggest you do the SPR thing with them (did I get the acronym right? It's been a while since I did one myself)


Cheers


P