CAD/CAM discussion forum > 3D CAD/CAM > What limits' sketcher in solving?

What limits' sketcher in solving?

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Paul

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posts: 326

Registered: 2011-9-17

Message 1 of 8

 What limits' sketcher in solving?
23-08-2010 04:50 . am | View his/her posts only
I am doing some sketches with lots of elements, fully constrained. I have reference curve that are splines and arcs and circles tangent to the ref curves amongst other stuff. Also some equations and variables are used. Definitely not you average sketches.
After a while Things seem to slow down a bit as I add elements which seems fair enough.
I reach point where adding a dimension or constraint fails and yet I cannot find anything over constrained when I Inquire.
I have discovered that deleted dimensions that used an equation do not clean out of the equation list whish seems and odd thing. They certainly don't help and having clear out can make a difference

So I am wondering what sort of limits are there as to what the solver will handle?
Are there (if so what are they?)conditions that are more demanding than others?
Chugg , chugg ...
I think it is doing a great job all considered (V14.4)

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Dave

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posts: 11

Registered: 2011-11-23

Message 2 of 8

23-08-2010 11:55 . am | View his/her posts only
Good Day Paul,

This probably isn't going to help, but have you tried freeing up memory ($$free).

I think I have also seen the equation editor leave deleted equations, but I'm not sure as I don't pay a lot of attention because on my relatively simple parts I don't see any impact.

Regards, Dave

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Paul

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posts: 326

Registered: 2011-9-17

Message 3 of 8

23-08-2010 03:27 . pm | View his/her posts only
Hi Daved,
maybe that is an issue but I run a memory manager anyway and it does a great job of keeping it free. I am not sure if the VX command cleans dirty VX memory or it is a generic OS command?

As a matter of interest I have made some discoveries about spline to arc tangency related to slowness - chugging.

In the pic attached, I am using the circles to set up the points for the curve. This is to create a relief cavity in the fillet of a press die. The media curve and the parallel curves do not deliver in this case. It is also being set up so that the beginning and end can be controlled by changing the offset dimension in an equation set to save entering the sketches. This will allow the client ot make their own decision as the where they want they feature.
The underlying geometry is not quite symmetrical and tweaks have to be made to match the curves at each corner set (14 all up) hence the long road.

So I set up the LHS circles easily with 3 point and tangency (you have to drift around a bit until the tangency indication shows up). (Seems odd to me that non tangent conditions would be accepted after setting tangency pick, but thats what happens) then mirrored to the RHS and deleted the sym constraint as the circles all missed the spline inside the top, outside the bottom, added the horz. dimensions The difficulty then arises trying to set up the new tangency cons. Some/most work some don't.

So heres the TIP.
Use RMB/Drag which will pick the circ/arc centre, RMB/Smart Pick Off/RMB Absolute (I really wish pick choices would at least endure for the sketch or until changed again) and adjust until the circle edge is just inside the spline close to where you want it.
Then when you add the tangency, it should work. I think this requirement is specific to splines due to the constant changing radius of curvature?
If you do not get the arc close enough to the spline it may error when infact a tangency can occur. Would be nice if the error suggested dragging the geometry closer...

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Dave

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posts: 11

Registered: 2011-11-23

Message 4 of 8

24-08-2010 09:36 . pm | View his/her posts only
Good day Paul,

This is so not what I do (it's great to be a simple meat and potatoes prismatic designer) that I hesitate to comment, so pardon me if I'm totally off the wall, but could precision be coming into play impacting the generation of the tangencies? Is the tolerance in preferences (edit pull down menu) suitable for mathematical requirements to create the tangency? I understand with surfaces (which this is not), if the math isn't deep enough, that gaps between the geometry will be too great. I don't know how many significant decimal places VX utilizing in its calculations.

I understand the construction method you are utilizing which is a very reasonable method. I'm wondering if the slow down has to do with the amount of math being crunched

Wish I could be more help, but I'm learning new things about the software from you all the time.

Regards, Dave

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Paul

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posts: 326

Registered: 2011-9-17

Message 5 of 8

30-08-2010 12:51 . am | View his/her posts only
Hi Daved,
learning all the time..... absolutely. Figure on being dead if you are not.

Re the slow sketch. The reason eluded but I no longer think it is complexity.
I copied and pasted the sketch contents for the other side of the die into another 'clean' sketch.
I had to move the elements and re constrain to a fresh set of reference lines.
Now the curious thing is that the second sketch is as complex as the first one but was not slow at all.
All the tangency's popped in perfectly regardless of location.

So my guess is that there was some rogue geometry hiding in the sketch somewhere. Just which and where will likely remain a mystery as I don't wish to go back there unless someone is paying!
Customer has machined and is happy.

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cutter

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posts: 56

Registered: 2011-11-23

Message 6 of 8

30-08-2010 08:44 . am | View his/her posts only
Hi Paul,
There have been times where I have had problems with creating geometry especially when there were numerous edits. I have had times where parts would get so slow that it was hopeless. While I never found out the problem my eventual solution was one of two. First was to export and bring the file back in as a VX part and next as an iges if the VX part did not work. Something about the round trip cleared up the problem most times. The second is starting over. I found wrestling with a problem where the cause could not be identified by Mike or myself took so much time that it was not worth it and begining over was much quicker. I just had to spend the time to get to the point where I decided it was not salvageable.

Sometimes on my setup I have found that other programs idling in the backround caused quirky behavior. This past week SE would just freeze up and it turns out that the culprit was a screen capture program. When I shut down all uneeded applications through task manager the problem went away--- after way to much time was spent trying to figure out why. I don't remember the specifics but I have had these conflicts with VX to in the past year also.

I am also coming to the conclusion that as my hard drive ages and sectors drop out or files are corrupted for whatever reason that even though my programs still work they do not do so as well. The things lost in files or from the bad sector may not be show stoppers but I wonder if they contribute to mystery problems. I am seriously considering the idea that those who reinstall their OS on a wiped hard drive when strange behavior appears that is not from malware may have the right answer to those strange problems that pop up and no one seems to have the answer as to exactly why.

Last and maybe not least is buggy software which has also been a big problem. Good luck on it and keep us posted on what you find out.
Dave

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Paul

Moderator

posts: 326

Registered: 2011-9-17

Message 7 of 8

30-08-2010 02:10 . pm | View his/her posts only
Hi Dave,
there is absolutely no question the leaner the PC setup the better CAD software runs.
I have mentioned my SWx mate here before, who, reboots his machine at least once a day and defrags everyday just to keep things ticking along.
Accumulated background programs are a big pain. Most stuff you use occasionally but it runs a little app in the background all the time. You need a good start up manager to kill them off and a good registry cleaner.
The only tip re sketches that come gluggy after 'lots of editing' is to blank all the elements you can see, then do a large selection and see if it picks any you cannot see. Older versions where good at zero length lines. V14 doesn't seem to do that.
Cheers

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Dave

Newbie

posts: 11

Registered: 2011-11-23

Message 8 of 8

30-08-2010 03:32 . pm | View his/her posts only
Hi Paul,

Your SWx Mate probably already knows about it, but I used to use Ecosqueeze (www.ecocom.com) for cleaning up Soldiworks files. It worked very well.

I don't know if the "$$free" utility inside of VX works on the VX file, but I think so. At least the message I get when I use it seems to indicate it is cleaning the VX file. If so, great, if not, it would be nice to have a product like Ecosqueeze for VX as it defrags the specific file.

When I first started with VX, I noticed the files appeared larger than comparable designs in Solidworks or Alibre. If it is storing surface data rather than solids, this is to be expected. I noticed significant slow downs. I have not been bothered by that as of late. Whether it is smaller files, the compaction utility, improvements in my disk defragmentor or what I don't know.

Regards, Daved
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