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Rigoberto131-Visitor
1-Visitor
November 3, 2014
Question

Many rounds on a LARGE part

  • November 3, 2014
  • 4 replies
  • 8305 views

Hi guys,

I'm new to the community and I'm hoping someone might be able to provide some input on an issue I'm having. I'm currently working a very large part with a very large number of features. I'm sure there are bigger parts with more features out there though. This part is at around 7500 features and I'll probably be shy of 8000 when it's done.

I'm trying to put in rounds into corners, as this part will be CNC machined. I've put rounds in about half of the part, but I've reached a point where when I create a round feature, which may contain some 30-40 edges, I have to wait like 10 minutes to generate the feature before I move on the next one.

I can give my machine specs in detail later but It's 16GB ram, 3rd gen i7 and the task manager says I'm using only about 6GB of RAM (including other programs/tasks) and less than 20% of my processor when the round is generating.

The part uses 0.001 absolute accuracy. It was at 0.0001 relative but I have a fair amount of short edges that are unfortunately a necessity for this part.

Anyone have recommendations on speeding up the rounding process? Or know of some limits of the round feature that I'm possibly violating?


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4 replies

J
JonathanHodgson13-Aquamarine
13-Aquamarine
November 3, 2014

Hi Peter,

I'll accept that as a 'large part'!

The low processor usage you're seeing is because regeneration in Creo is essentially a single-thread process, so your 4- or 8- core i7 is sitting up to 75% or 87.5% idle. My only thought there would be to try disabling hyperthreading in the BIOS and see whether it makes any difference - don't be surprised if it doesn't, though.

Other than that, for a complex part such as yours I don't know where the optimum balance is between putting lots of round sets in a few features, or having more round features with just one or two round sets each. Historically Pro/E has preferred many simple features (and complex round features do seem to get slow) but again, a back-to-back test might be interesting if you feel you can spend the time.

Absolute accuracy is usually the way to go so I'd stick with that, unless anyone knows otherwise.

HTH (a little!)

R
Rigoberto131-VisitorAuthor
1-Visitor
November 3, 2014

Thanks for the quick response, Jonathan.

Haven't thought about disabling hyperthreading (frankly I don't know if my BIOS will let me but it's worth trying).

I've played around with creating features that are smaller in set size and it does indeed generate faster. But what I'm seeing (without formally timing it) is that generating 3/4 features of say 30 edges with maybe 10 per set, will generate in about the time one feature 120 edges will take, maybe a bit faster. But at that speed...I'm still not moving very fast.

J
JonathanHodgson13-Aquamarine
13-Aquamarine
November 3, 2014

Other than that... can you perhaps suppress half (or more) of the model at a time (internal vs external features)?

My colleague who mostly works on castings says that his models are only up to 2000-2500 features fully filleted, and he thinks they're slow!

tbraxton
tbraxton22-Sapphire II
22-Sapphire II
November 3, 2014

These suggestions are highly model dependent and I personally have no experience with a part having in excess of 1000 features. I have built part models that require in excess of 1000 features to create but not all in a single model (see #2). There are three things that come to mind which may help. These can be employed independently or in conjunction as required. If your issue is exclusivley one of 100+ edges in a single round feature these will probably not do anything to improve the situation.

1) Set as many features as you can to be read only so that they are not regenerated. Rounds can force regens far upstream from where they are in the history of the model. Be mindful of the ramifications of saving a model with read only setting on features if you use this technique.

2) Use Merge or Inheritance functionality to define a large portion of the model features in a parent model and make the child model independent while creating the rounds. when the design is complete reset the dependency to the parent object.

3) Be considerate about the order in which intersecting rounds are created. Hard to verbalize but this can have an impact on regen of rounds in large models. I think there have been some presentations on using round functionality at Pro/User events and you may be able to find a copy for more of an explanation.

    M
    MauroStefanovic1-Visitor
    1-Visitor
    November 3, 2014

    I really appreciate your suggestions, Thomas.

    R
    Rigoberto131-VisitorAuthor
    1-Visitor
    November 3, 2014

    So on the above comments:

    I've considered doing something "nested". Like using a shrinkwrap to make the bulk of the part, and then doing the rounds separately in a part consisting of said shrinkwrap.

    I have my graphics settings as low as I can afford to go.

    I'm not too familiar with Merge or Inheritence unfortunately,

    I'm pretty careful with the order I create the rounds. Or at least I think I am, one of those presentations might not hurt.

    I'm also not too familiar with using read-only features. I don't know if I can afford to do that. I haven't really had any issues with rounds causing regens up the tree. The only regens I've seen are the ones I force or knowingly cause by changing something myself up the tree.

    I think the big issue is simply that I have a couple thousand rounds and the software doesn't seem to easily keep up with so many rounds in one part. Creo is better than Pro5 was, I'll admit that, though. I'm sure not a lot of people have used the PTC suite to make parts as large as this one so perhaps PTC hasn't had a lot of reason to look into this issue.

    tbraxton
    tbraxton22-Sapphire II
    22-Sapphire II
    November 3, 2014

    I have not had good luck with the robustness of shrinkwrap for something like this. Merge or inheritance would be better suited to breaking up the model into two or more separate part files IMO.

    Read only setting can be set and cleared, you can set features to be read only and clear that flag at any time you like. It can cut down on the regen time of a model. Since you can turn this off at any time there is no risk to testing it out on your model to see if it helps. Set all of your model features up to the point you create a round to read only and then create one of your round features and observe the regen time. If it is a model issue you will notice, if it is a feature regen time it will make no difference. Pro/E has always been computation intensive for round intersections so I can easily see 100+ edges in a single feature taking a long time to regen. If it is a feature issue then I would use many more features to create the rounds.

    PTC mantra (for Pro/E) is more numerous simple features is preferred to fewer more complex features.

    R
    Rigoberto131-VisitorAuthor
    1-Visitor
    November 3, 2014

    I see Thanks for clarifying read-only.

    Forgive me but I want to make sure you understand the issue.

    My model regeneration time before rounds was bad, but I'd say on par with normal parts modeled with this accuracy. It's just that I have a lot of features.

    I'm concered with the fact that when I hit the check-mark after selecting a group of edges, it takes a fair amount of time to get from check-mark to a point where my screen shows rounds. Further, if I'm regenerating only rounds (say a group of 3 or 5 rounds near a feature of the part) they individually generate slowly.

    I've already broken my tree down to use multple round features with less edges per feature, but the time it takes for 10 features of 10 edges each is about the same as 1 feature with 100 edges, it just convenient for debugging at that point.

    To further clarify, I did set my tree to read-only and then created a round set to verify this, and there is no noticeable change.

    R
    rreifsnyder15-Moonstone
    15-Moonstone
    November 9, 2014

    I might check on adding the rounds as surfaces in chunks of adding material and removing material. The tricky part would be where the adding and subtracting meet. They could be merged in groups and solidified as cuts and material adds. This may or may not be any more work. The concept behind this is that from my conversations with PTC tech people, a lot of time in geometry creation is the checking that has to be done to make sure it creates a valid solid. By grouping that work into fewer solidifies the idea is that it might go faster.

    I would actually think that the whole part could have been made with surfaces. The rounds could be eaisier to deal with because you can have them add or cut just like working in solids. I have done some work with Fisher-Price, and a lot of times they model with surfaces and use symmetry by modeling everything as half the part, with the last 2 features being a mirror and solidify. I know it WAAAAYY to late for this approach and I honestly have never tried modeling the same complex part with both methods, but it seems to make some sense with the idea of how geometry patterns work SO much faster than feature patterns.

    T
    TomD.inPDX17-Peridot
    17-Peridot
    November 9, 2014

    Below is a long discussion we got into and learned the same thing about solids. It seems it does a deductive algorithm to determine the solids, meaning is does one feature at a time, and with a single CPU core, this is simply intolerable. 1 of 10, 2 of 10, 3 of 10... 10 of 10, 2 of 10, 3 of 10... ...9 of 10, 10 of 10, 10 of 10, so to do 10 features, it cycles 55 times during the regeneration. At least, that is what the delays in the linked part seem to be doing. It would regen features over and over again.

    Feature Failure with Repeating Patterns

    In the end, making solids of merged quilts was much faster. Which is totally counter intuitive in what presents itself as a solid parametric modeler. More surprising is that it didn't matter if the "rods" were square or round.

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