Mechanical geometry "tolerance"

[ThorA]

Hi,
We have many large circular components that we import from Siemens NX. No Ansys geometry modeller.

In some cases it becomes very difficult to select graphics and is quite an annoyance that the geometry is very coarse. The circular edges are not circular at all but an n-sided polygon, where n is too low.

Is there a setting/procedure that makes these polygons to be finer?

I have changed the options Mechanical:Graphics:Number of circular cross section divisions to 256. But this is obviously something else...

Thanks in advance for any tips.

NX10
Ansys 16.2
HP Z820 / Quadro4000

 

[Dave442]

Hi,

Are you sure the geometry is actually polygonal and the pre-processor is not just set to coarse curve refinement (which is the default in other FE pre-processors like Abaqus)? The meshed circular components in the lower image are much more circular than the geometry shown in the first image.

Good Luck,
Dave

 

[ThorA]

Hi,

If you mean pre-processor as NX, it is not polygonal, it is circular in NX before I import it. As far as I know there are no controls in the geometry Interface of NX-Ansys.

Geometry in NX is still graphically polygonal, but much nicer:

Ansys understands that this is circular in the meshing.

But I was able to experiment a little bit. It turns out it's NX that decides how this is shown in Mechanical.

If I changed Visualization Preferences:Resolution:Standard to fine or ultra fine it became much nicer:

So it is now solved!

Thanks for the pointer!


NX10
Ansys 16.2
HP Z820 / Quadro4000

 

[Dave442]

This is exactly what I meant.

In many CAD-based packages curve resolution/refinement is set to coarse/low by default for optimal performance. As you saw when you meshed your "polygonal" part, however, the underlying geometry is still correct.

Dave

 

[omidomidi]

Yes, I have encountered to such problem in solidworks, solidworks has an option "tessellation" that is you decrease it then you will see the curves like a polygon and it's something only graphically you see but in reality it is a curve and when you mesh it in an FE software you see that it is a curve.

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