Inventor General Discussion

Inventor General Discussion

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Contributor
randym19ca
Posts: 11
Registered: ‎12-01-2006
Message 11 of 44 (322 Views)

Re: speeding up constrain execution

10-23-2012 01:08 PM in reply to: eleblanc

Have you tried disabling "Enable constraint redundancy analysis" and "Enable related constraint failure analysis" in Application Options / Assembly tab?

Distinguished Contributor
eleblanc
Posts: 124
Registered: ‎10-30-2006
Message 12 of 44 (315 Views)

Re: speeding up constrain execution

10-23-2012 01:25 PM in reply to: randym19ca

randym19ca wrote:

Have you tried disabling "Enable constraint redundancy analysis" and "Enable related constraint failure analysis" in Application Options / Assembly tab?


Yes, no change. It really is when i supress constraints that things gets speedy again. I'm sure the Autodesk team is well aware of this.

Employee
steven.dennis
Posts: 132
Registered: ‎10-23-2007
Message 13 of 44 (306 Views)

Re: speeding up constrain execution

10-23-2012 01:43 PM in reply to: eleblanc

Hello guys,

 

 How many constraints at the top level are we talking about?

 Are you using adaptivity?

 Are you using flexible sub assemblies?

 Are you using Positional Variations?

 

To answer the one question directly, no we do not rebuild the parts to validate geometry unless those parts are out of date.

 

Remember that one difference between Inventor and competitors is that Inventor is a variational solver not parametric, so the entire system is resolved every time rather than building one constraint on top of another like you can do in a parametric system.  A variational solve can change in another part of the system with an additional constraint, the solution varies on the entire system of relationships.  i.e. right field changes CAN affect left field.

 

Subassemblies are a good solution, grounding things that are located correctly should help, making sure at least one thing is grounded should help (i.e. a starting point)

 

The solver attempts to remove Degrees of Freedom based on the SET of constraints.

 

I hope this helps.

Questions?

 

WOuld you be able to share your dataset for us to look at?

 

 



Steve Dennis
Sr. Principal Engineer
Inventor
Autodesk, Inc.

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JDMather
Posts: 28,262
Registered: ‎04-20-2006
Message 14 of 44 (302 Views)

Re: speeding up constrain execution

10-23-2012 01:47 PM in reply to: eleblanc

eleblanc wrote:
 It really is when i supress constraints that things gets speedy again.
I'm going to suggest an experiment that you might find a bit of work.
Go to Modeling View.
Expand the Constraints folder.
One-by-one suppress them (only one at a time or only those on a particular part).

Does it suddenly work fine.
In my experience it usually turns out to be (user) an error in logic.
Sometimes it is with a bad part (in fact I can usually zero in on the problem constraint pretty quickly without going through them all as I have seen what typically causes the problem over and over again.
Is anyone looking at your dataset?

 

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JDMather
Posts: 28,262
Registered: ‎04-20-2006
Message 15 of 44 (301 Views)

Re: speeding up constrain execution

10-23-2012 01:49 PM in reply to: stevec781

stevec781 wrote:

.... checked by my VAR's best trainer who found nothing wrong ....


 

 

Time to find another VAR.

 

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Distinguished Contributor
eleblanc
Posts: 124
Registered: ‎10-30-2006
Message 16 of 44 (298 Views)

Re: speeding up constrain execution

10-23-2012 01:55 PM in reply to: JDMather

JDMather wrote:

eleblanc wrote:
 It really is when i supress constraints that things gets speedy again.
I'm going to suggest an experiment that you might find a bit of work.
Go to Modeling View.
Expand the Constraints folder.
One-by-one suppress them (only one at a time or only those on a particular part).

Does it suddenly work fine.
In my experience it usually turns out to be (user) an error in logic.
Sometimes it is with a bad part (in fact I can usually zero in on the problem constraint pretty quickly without going through them all as I have seen what typically causes the problem over and over again.
Is anyone looking at your dataset?

 


JD, i did not go as far as supressing them one by one, but i did so with a increment of about groups of 10-15. And the speed gradually got worse as i unsupress constraints. It wasn't a case of no change then sundenly all slow, like a culprit would be in that last groups of 10-15 i just unsupress.

If i have a chance i will get the whole thing in my private dropbox for you to give it a shot if you want.

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JDMather
Posts: 28,262
Registered: ‎04-20-2006
Message 17 of 44 (288 Views)

Re: speeding up constrain execution

10-23-2012 04:29 PM in reply to: eleblanc

eleblanc wrote:
If i have a chance i will get the whole thing in my private dropbox for you to give it a shot if you want.


Somewhere up above Autodesk also requested the dataset - I assume the Desker has more time for this sort of trouble shooting than I have.  I would only be able to give it a few minutes. (but maybe that is all it would take - sometimes it just takes another set of eyes to see the obvious)

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Valued Mentor
stevec781
Posts: 691
Registered: ‎05-29-2009
Message 18 of 44 (268 Views)

Re: speeding up constrain execution

10-24-2012 06:29 AM in reply to: steven.dennis

steven.dennis wrote:

 How many constraints at the top level are we talking about?

 Are you using adaptivity?

 Are you using flexible sub assemblies?

 Are you using Positional Variations?

  


Thanks Steven, can you elaborate more about how Inventor thinks. 

 

To answer your questions above, not many, rarely, no, no.  I try to ground and use derived component wherever practical.

As an example my very top level asm has 381 occurances and 378 open in session, so not large.  I have a sub assem called cabin which is grounded at 0,0,0, It then has a dash sub assem (grounded at 0,0,0),  which has a dash part (grounded at 0,0,0).  The dash part has one adaptive sketch with 1 edge referenced.  The dash face has a hole in it.  To make a quick drawing I dropped a steering wheel in at the very top level and used an insert mate to mate the base of the wheel to the hole in the dash.  After a complete rebuild and save I rotate the wheel by dragging it.  Inventor thinks for about 4 seconds.  When I then press save I get as below.

 

save box.jpg

 

I cant understand why a simple drag has caused so many updates, and even more confusing is why the fuel tank is one of them.  My VAR spent 3 hours trying to figure out what is going on with no luck (I cant find a new one as they are the only ones here), so that was a waste of 3 hours of my time.

 

Maybe if you can explain more about how Inventor thinks I can figure out what is going on here.

 

Another maybe related question, why does the productivity tool ground and root component also add mates to all the planes?  Does inventor still require mates even when a part is grounded?

Employee
steven.dennis
Posts: 132
Registered: ‎10-23-2007
Message 19 of 44 (261 Views)

Re: speeding up constrain execution

10-24-2012 06:46 AM in reply to: stevec781

Steve,  you're not the original poster right?  I'm just a bit confused.

 

Explaining how Inventor "thinks" would take more than i'm willing to type and is specific to each solve set.  My original explanation of variational vs. parametric will have to suffice for now w/o specific data.

 

You said "not many" constraints, how many is that?  How many do YOU think is not many?  Our idea might be different.

The adaptive sketch will impact solve time.  HOw much is not clear w/o data.

 

You said after a complete rebuild?  What exactly does that mean? You used the rebuild all command?

 

If you did of course that will dirty sub assemblies and parts.  I doubt the drag caused the dirtying.

 

If you can supply the dataset we can discuss specifics but trying to explain all the cases here would be fruitless I'm afraid.

 

The productivity tools were not written at autodesk, they were "consumed" by us and published I think.  I have no idea why ground and root does what it does.

 

 



Steve Dennis
Sr. Principal Engineer
Inventor
Autodesk, Inc.

Valued Mentor
stevec781
Posts: 691
Registered: ‎05-29-2009
Message 20 of 44 (244 Views)

Re: speeding up constrain execution

10-24-2012 09:28 AM in reply to: steven.dennis

Hi Steve

No not the OP, I posted 3rd.  But still on topic of slow performance caused by mates.

 

I didnt want to open and count the constraints, but at a guess 20% of parts/assem are placed with constraints, about 80% grounded with no constraints.  About 10% with adaptive sketch, 90% using derived workflow.  Total occurances in project less than 400.

 

I understand that associaive sketches will impact rebuild time when parts are edited, I just dont get why dragging parts and adding mates are causing rebuilds in unrelated parts.

 

Complete rebuild means rebuild all, then save, then save again just be sure 100% sure everything is up to date and saved.  Then rotate the wheel and press save to get supplied screen shot.  The rotate is affecting the other parts.

 

You can see the steps here http://screencast.com/t/tNhBkVlmw

 

 

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