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Parts Disappear on Show Mesh, Reappear on Hide Mesh

Question asked by John Willett on Apr 9, 2017
Latest reply on Jan 10, 2018 by Aaron Hayden

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Solidworks Premium 2017 SP2.0 under Windows 7 SP1 -- In a linear static study two display anomalies started suddenly, and I can't get rid of them:

1) When I mesh the model, several parts disappear, only to re-appear when I hide the mesh. Here is a pair of images where the only change is between showing and hiding the mesh:

2) Six of the parts are set to "Exclude from Study" (see above). Only three of them disappear from the simulation window, although the other three are shown but gray, until the mesh is shown:

Neither of these issues showed up until several meshing adjustments were made. Then they suddenly appeared together. Closing and re-opening SW has no effect. Neither does logging off and back on. In case it matters, I'm using curvature-based meshing with several mesh controls, all done before.

Anyone seen anything like this? Know how to fix it? -- John Willett

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Ryan Dark Apr 10, 2017 3:34 PM
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Hi John,
From the description you have here it would seem like the mesher is failing to mesh certain bodies in your model. The mesh can't show a body that was not successfully meshed. It should, however, report that there has been a mesh failure to certain bodies. Failing that though, the body list in the study boundary tree should show the failing bodies with a red hatch on the icon (instead of the green hatch you are now seeing).

In any case, you may want to try editing the definition of your Global Bonded contact and set it to be an "Incompatible Mesh" and see if things don't get better in the mesh.
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- John Willett @ Ryan Dark on Apr 12, 2017 5:37 PM
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  Ryan -- Good suggestions, but it turned out to be even weirder. First I had a hidden part that was free to move and not excluded from analysis, hence solver failure. After I fixed that, I could see the mesh and run a study, but when I tried to save all, it told me some of my assemblies were corrupt and could not be saved. The eventual solution (so far) was to re-build the model from older versions, but without some of the parts that were to be excluded anyhow, and start again... -- John Willett
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- John Willett @ Ryan Dark on May 2, 2017 8:54 PM
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  >>From the description you have here it would seem like the mesher is failing to mesh certain bodies in your model... It should, however, report that there has been a mesh failure to certain bodies. Failing that though, the body list in the study boundary tree should show the failing bodies with a red hatch on the icon (instead of the green hatch you are now seeing). ...you may want to try editing the definition of your Global Bonded contact and set it to be an "Incompatible Mesh" and see if things don't get better in the mesh.<<
  
  Ryan (and others) -- Here we go again with a more complex but closely related model showing a nearly identical problem:
  I seem to have fixed the problem in the previous model, but here the same five parts ("cell ring," "cell base", and three copies of "screw block") are invisible in the mesh display:
  There are no red "flags" on any of the parts (the previously troublesome one that is just a template for copies, "pad-1" has been excluded from analysis), nor were any mesh-failure messages displayed. I've tried compatible, incompatible, standard, and curvature-based meshes, all with the same result.
  
  For what it's worth, here are the mesh details:
  Only one idea so far: What happens if there are too many elements in the study (as there are for the Intel Direct Sparse solver on my 32GB machine, although it doesn't complain until it's "Establishing element connectivity" with 4,293,066 DOF)? Could that cause meshing problems?
  
  I will try forcing the number of elements down, but that will be difficult given the essential details in the model... -- John Willett
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  - Ryan Dark @ John Willett on May 2, 2017 10:22 PM
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    Hi John,
    I am honestly not sure what is happening with your mesh at this point. The images would lead me to believe that the program thinks the bodies have been excluded, hidden, or failed to mesh. None of these seem to be the case though. At this point I would normally ask to do more testing on my end but I don't know that this is possible for your company. If you can, I'd be happy to take a look.
    
    Other than that, I don't think that the solver type would have anything to do with this. There could be an issue in the mesher though. I would expect 32 GB of RAM to be enough to not run out as I have meshed models this size with less RAM before.
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Andrew Cuttle Nov 16, 2017 3:52 AM
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I am getting the same issue with a shell model.

No error messages either but there are various bodies that don't seem to want to mesh? Looking at it again fresh this morning I discovered it had lost the shell thickness for these parts and rather than producing an error message, as is normal it would, it automatically excluding these items from the analysis.

Re-applying the thicknesses fixed some of the disappearing bodies, looking further I found that some other bodies had individual missing faces which had to be fixed by redefining them as shell members.

The fact that this all happens without any error messages and is very time-consuming to fix I find very frustrating. It certainly means I'd never use simulation by choice as it stands currently.

I'd suggest the common issue in both our cases is the model failing to mesh bodies whilst producing no warnings that it has done so and looking in the tree the excluded bodies aren't highlighted, I only saw them in the shell-manager.
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Colt Carson Dec 4, 2017 5:38 PM
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I was having the same issue in 2017 sp4.01.

What worked for me was to go to the model tab and create a new dummy configuration and make sure it is active.
Next go back to your simulation tab. Everything should be grayed out because the proper configuration is not active.
Then right click on the study and select 'activate sw configuration'. This seemed to do a fresh update of all the components and their meshes became visible again.
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- John Willett @ Colt Carson on Dec 4, 2017 9:15 PM
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  Interesting... Your observation prompted me to post this not-so-new information from a SW Corp. tech. through my VAR. Maybe one of these suggestions will work for you too:
  
  "The best "quick" workaround that I found in my testing which does not require modifying the geometry or assembly structure is to use a Force Rebuild All (Control+Shift+Q)."
  
  The other work-around that the tech suggested is much more brutal. Having documented my problem as SPR 1029132 - "Cut extrude features on subassembly that are not propagated to part level prevent proper mesh display - component meshed but hidden/missing in mesh view," he suggested:
  
  "enable the 'Propagate feature to parts' option for both Cut Extrude features."
  
  Good luck! -- John Willett
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  - Colt Carson @ John Willett on Dec 5, 2017 9:43 AM
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    Thanks for the tip, that is much easier!
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- Aaron Hayden @ Colt Carson on Jan 10, 2018 5:21 PM
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  I too have had issues with meshes suddenly disappearing with 2017 SP 4.1. Creating a new study and copying fixtures, loads, and connectors from the original study would temporarily fix the problem but it eventually would just come back. Just today I had a case where the assembly would mesh with no issues, the study would run fine, and report results accordingly. However, when I saved the assembly, closed, and re-opened some of the meshed components would disappear. The results also changed and would no longer report anything on the components that disappeared. No amount of adjustment to the mesh would fix it nor were any meshing errors thrown. The icons in the parts group drop down showed that they were meshed, yet they were not. Long story short, switching between configs brought it back to reality. I saved after switching configs (don't know if that mattered). Once I switched back to the correct config all meshes appeared and the results reported as they did orginally. I did not have to remesh nor rerun the study, just flip flop configs.
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Parts Disappear on Show Mesh, Reappear on Hide Mesh

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