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I can't apply contacts between parts due to mesh problems

Carlos Fondevila

Hy all,

I have problems with the contact of a CAM in a 3D model, Motionview gives me the next message:

I try to improve the mesh coarseness to the top (10 value), but the mesh is still poor:

I I recive the same message when I try to run simulation.

There are forms to improve better the mesh of the geometry?

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MotionView/MotionSolve

Accepted answers

All comments

GTT Adam

Hi @Carlos Fondevila,

I'm sorry you're having trouble with your contact settings. Are you trying to model either of these bodies as flexbodies or are they both rigid? Have you considered using 2D rigid to rigid contacts instead?

Can you attach the model here for review?

Hope this helps!

Adam Reid

Carlos Fondevila

Hi @GTT Adam , I think that I'm working with rigid bodies.

Attached you can find the file:

MotionView Model.zip

GTT Adam

Hi @Carlos Fondevila,

Can you please provide the model as a zipped model archive?
(File >> Export >> Model >> Archive Model & Create Zip File)

Otherwise the graphics are not sent as well.

Hope this helps!

Adam Reid

Carlos Fondevila

Yes Adam.

Thanks!

Model 1_archive.zip

GTT Adam

Hi @Carlos Fondevila,

When I run the model, there is no contact issue as you have described. The yellow piston moves the yellow cylinder up as it contacts the cam. The only issue seems to be that one of the pistons (coloured green) is not reacting against anything, so once it encounters the cam it shoots off into space:

I think the only missing entity is a joint between the green piston and the yellow cylinder to complete this model.

Hope this helps!

Adam Reid

Carlos Fondevila

Hi Adam,

In wich version of MotionView did you run the model?

GTT Adam

Hi @Carlos Fondevila,

I am running the most recent release, version 2024.1

Hope this helps!

Adam Reid

Carlos Fondevila

Ok Adam,

We are using the same version but in my computer it doesn't works.

GTT Adam

Hi @Carlos Fondevila,

Please try the following:

Unzip the archive you just made.
Open the model in MotionView.
Reset all of the Global Simulation Settings for Static, Transient, Linear, General, Result, and H3D.
Simulate the model.

Hope this helps!

Adam Reid

Carlos Fondevila

Hi @GTT Adam

If I open the Zip file and run the simulation, at first it runs.

But if I change any value (for example the rotation speed, or any value of the contact like damping or stiffness), the model give me again the same error:

Even when I restart the simulation parameters to default.

But the point is, If I close the program (all this new values are saved) and I open it again and run the simulation, the model runs correctly…

Carlos Fondevila

Yes, the problem occurs when I change any parameter, if I run the model, during exporting geometry, appear the error…

GTT Adam

Hi @Carlos Fondevila,

Unfortunately I am unable to produce the "failed to read triamesh" error with your model.

There were some issues with the model that I would recommend you address:

The Message Window had an error displayed for the "support motor" graphic in that a graphic component was not selected. After selecting the appropriate component, the body is defined.
The pistons looks to start in contact, which is not recommended. I added 5 mm of separation and changed the simulation type to Static + Transient. This way, the model will initialize the contact in a more appropriate way.
The "Pisto" part is deriving its physical properties from graphics, but that produces a body mass of only 0.01 kg. It also does not have any upper limit to displacement, so if a contact force is encountered with its low mass it will shoot off in the +Z axis. The "Pisto 14mm" has the ~1kg mass attached to it which prevents the same thing from happening. Should the "Pisto" have a mass attached to it as well?
The naming of the pisto parts may actually be causing issues, as the "ó" is a special character. I renamed it in the model and do not experience the rerunning issue anymore.

Model_3_archive_archive.zip

Hope this helps!

Adam Reid