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pclahane1-Visitor
1-Visitor
March 3, 2017
Question

Help with large assemblies and structures

  • March 3, 2017
  • 3 replies
  • 6986 views

My organization performs modifications to vehicles, and I would like to know how to better structure our assemblies to decrease load times and increase computer performance. At the moment we have a very bottom up approach to assemblies, where the parts are modeled, then placed in assemblies, which are then placed in installation models. These installation models typically contain a model of local vehicle structure which we will be using to attach our parts and assemblies. Finally all installation models are rolled up into a general arrangement model, which contains a full layout of the vehicle. This approach has worked out well enough for us in the past on smaller projects with only a few installations. However, this approach is not ideal on large projects with many (15+) installations, containing thousands of parts (hardware, designed parts, and reference structure), especially when multiple installations reference the same structure (this means the same structure would appear multiple times in the general arrangement assembly).

What I would like to know is if its possible to take a top down approach; where, the complete vehicle structure is found in the highest level (general arrangement) assembly, and each installation (next lower level assembly) can reference its necessary structure? I know skeleton models can work in a similar manner to what I have described above; however, I do not know if its possible for this reference structure to appear in the installation level drawings. Any help would be appreciated, thanks.

3 replies

Chris3
Chris321-Topaz I
21-Topaz I
March 3, 2017

There is no one thing that will help significantly. You are going to need a combination of things. Unfortunately there aren't a lot of really good specific examples out there.

Reading Material:

Steven LaPha's presentation here is one of the better I have seen: Bringing Large Assemblies Down to Size‌

Tips (in no particular order):

  1. Look into interchange assembly substitutions. This is an often overlooked feature that can help a lot.
    Creo Parametric Help Center
  2. Do not use assembly level cuts. Assembly level cuts create behind the sceens family tables and can drastically effect performance. If you have to create them make sure to uncheck the automatic update box and manually pick the components you want instead.
  3. Use simplified Reps. Creo 4 does a better job of dynamically turning these on and off for you automatically as needed.
  4. I know Caterpillar has used collapsed geometry in order to speed up regen times. You might want to look at that. Features can be moved with flexible modeling afterwards if needed.
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BrianTaylor8-Gravel
8-Gravel
March 17, 2017

What are you doing for Match drilled parts where you assemble a part in place with Cleco's match drill all holes and install say a hi-loc or other permanent fastener.  The better option is to explicitly set what tow hole you intersect with the assembly cut then to say no assembly cuts.

Chris3
Chris321-Topaz I
21-Topaz I
March 20, 2017

You can put the hole in the piece parts and then turn it off with a simplified rep at the piece part level. Yes as I stated in my original post if you have to create them then it is best to explicitly state which components are being intersected.

The criticality of assembly level cuts depends on the size of assemblies you are working on.

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23-Emerald III
BenLoosli23-Emerald III
23-Emerald III
March 3, 2017

Search the community for Large Assembly and follow some of those tips.

Here is one that deals with large assemblies: Bringing Large Assemblies Down to Size

Learn how to use and manipulate simplified reps as they help reduce the load when working with the top assemblies.

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MtnDog10-Marble
10-Marble
November 14, 2017

He says in the presentation on page 24 "You can use the out of the box symbolic rep on lower level components or you can have it show sketched lines or datum curves, even those used for things like AFX frames, piping, and cabling as shown here."

 

Does anyone know how "you can have it show sketched lines" in a symblolics rep?  Simp Reps don't allow features to be shown or not.  Combined States have layer's, but you can't make a next higher level combined state with lower combined states. 

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BrianTaylor8-Gravel
8-Gravel
April 4, 2017

My single biggest suggestion to you is to utilize envelopes for any and all assemblies.  View, Envelope Manager, Create, pick all the parts, drops you into a creation prompt in my experience surface creation is the fastest and lightest weight.   After you are done creating it, create an Next higer assembly rep  NHA or what ever and then substitute in the envelope into that new rep.   We then create drawing reps and then substitute in those lower level NHA reps....

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