Rebuilding... Over & over &over &over...

Does anyone know what would cause an assembly to keep rebuilding over
& over after every move I make? After every mate, axis inserted, or
sketch editied, it rebuilds & rebuilds ten to fifteen times for one or
two minutes. It took me ten minutes to position three parts in a
small assembly of a mold. It seems to be rebuilding the same part over
& over.

This mold has three main parts & about ten pieces of hardware (pins,
bushings, etc...), so it should not take more than a couple of seconds
to rebuild.

Could a circular reference cause this? If so, how would I find it?
Maybe it is something completely different. I'm using 2004 sp2.1.

Because of this I am being paid to watch an hour glass & bang my head,
and be completely non-productive. If anyone has a suggestion as to
what could cause this, please let me know. Thanks in advance.

 

(oredock13) wrote in @posting.google.com:

Yeah, circular references are easy to create. The only way to find a
circular reference that I know of is to RMB on each part in the assembly
and "List External Reference". Then write down the part that is doing the
referencing in one column and the part being referenced in another column.
If you go through all of the parts and find parts that are in both columns,
and can see a loop like A-B-C-A, you've got yourself a circular reference,

There are a couple ways to avoid circular references. One is to use an
assembly layout sketch and only reference that with other parts. Another
way is to keep your references going up the assembly tree. You'll need to
put the most driving parts in at the top of the tree to do this. If you
avoid making references going down the tree, then you'll avoid circular
refs.

good luck,

matt

 

Sounds like in your options you have backup set to every one rebuild.
Because adding a mate, or any of those things you mentioned are done it
rebuilds which in turn would make it rebuild

Neil
www.solidworktips.com

 

Having Animator Screen Capture on would do this.

 

cadML tools (www.cadml.org) can document your model with graphs that show
all mates, references and even equations. It should help you a lot to find
circular refs.

 

I found it, it was indeed a circular reference. After alot of right
clicking , rebuilding, and waiting, all of a sudden some 5 or six
errors appeared. That made it pretty obvious where my problem was. I
wish the errors would have appeared sooner.

Thanks to all who posted. Now I have a few more tricks up my sleeve
next time this happens.

I downloaded cadML, looks looks like a usefull tool. I'll check it
out as soon as I get a little time.

 

Sounds to me like we should all send in an Enchancement Request to add
another dialog pop-up (DOH!) to warn you that you are adding a circular
reference. Or maybe a simple symbol, sorta like how the lightweight feather
appears in the feature manager and on screen, to identify which parts or
assemblies have a circular reference.

 

Good idea (I had it before ;-) but quite hard to implement because:
1) not only references between parts, but also feature dependencies and
equations, and even mates might cause circular dependencies
2) cycle detection in graphs isn't trivial. It's simpler if you have the
graph stored in memory as a "minimum spanning graph", which is not useful
for other purposes (or perhaps to optimize multi processor usage in
rebuilds...) But if you have to rebuild the graph every time you add a
feature, it will take too long.
3) sometimes you'd want circular references. See the nice models from Mike J
Wilson which animate at each rebuild...

Check www.cadml.org for tools that let you display dependencies graphs of
your SW models. You're free to add a cycle detection algorithm (or to pay me
to do it ;-)

 

I haven't downloaded the app yet, but it sounds like what I've been asking
for. It takes me at least an hour to do an analysis on a 30-40 part
assembly to find all the relations.

Would it be any faster if you just stored the information in text format
instead of graphically? I mean all you need is the name of the part or
assembly level feature being referenced.

I submitted an enhancement request to SW for this last year when I had to
prove to a customer that he had created his own problem. By deleting a
couple relationships we took his rebuild time from 20 minutes to 30
seconds.

matt

 

get cadML. It's (still) free. Tell me how you like it, I'm still working
hard on it.

Actually cadML is a text (XML) format. The graph is an automatic
representation of ALL the dependencies (not only external references)
because "a drawing is worth a thousand words".
Consider that circular references might be "indirect" through feature
references, equations and even mates!
But if you want the references to be listed somewhere, it's a matter of
seconds to modify the cadHTML.xslt sheet to do that.

Wow!
Yes, it would be great to have a circular ref detection tool, but it's
definitely not easy. I'd be happy to get subcontracted by SW on this topic
;-)

 

On Tue, 24 Feb 2004 07:10:46 +0100, "Philippe Guglielmetti"

A circular referance warning would have been great but if it is hard
to implement, what do people think of the following: - A toggle
'button' icon that is apparent when people are working with assemblies
and have a part open ('pinked') for editing.


Using this button would restrict you to only selecting edges, faces
mates etc of the current 'editable' part in the assembly. This would
really be useful and would possibly reduce the amount of times I have
inadvertantly selected edges,etc belonging to other parts in an
assembly.

I expect someone is going to say that this can already be done! or
there is a hotkey for this. I do hope so, but I have lost my track of
all the new stuff they keeping putting into SW!! I am still getting
to grips with the new 'User manual' . I'm using SW2004 sp2.1




Regards


Jonathan Stedman