Surface has area of zero

Coreform Cubit
#1

Hello,

I have 2 surfaces in my model that are the exact same surface. One has a surface area of 0.05 and the other has an area of 0. This is before merging. When i imprint/merge these two surfaces they create one surface shared between the 2 volumes. However, the area of this resulting surface is 0. This is not helpful when using the meshing python script below.

Here is the output of the command measure surface # of the problematic surface.
Summary of Surface Measure Info*

Measured 1 surfaces: Average Area: 0.000000

Minimum Surface Area is: 0.000000 on surface 4198

Maximum Surface Area is: 0.000000 on surface 4198

Minimum Hydraulic Radius (Area/Perimeter) is: 0.000000 on surface 4198

Minimum Curve Length is: 0.090000 for curve 3644 on surface 4198

Maximum Ratio of Adjacent Curve Lengths is: 6.748601 on surface 4198

Minimum Distance Between a Single Loop is: 0.037242 on surface 4198

Minimum Interior Angle Between Curves is: 90.000000 Degrees on surface 4198

Maximum Interior Angle Between Curves is: 0.000000 Degrees on surface 4198

Centroid of Surface 4198 located at: ( 0.362100 , 0.479630 , -0.276913 )

*End of Summary

Here is before merging
Summary of Surface Measure Info*

Measured 2 surfaces: Average Area: 0.027332

Minimum Surface Area is: 0.000000 on surface 4198

Maximum Surface Area is: 0.054664 on surface 4254

Minimum Hydraulic Radius (Area/Perimeter) is: 0.000000 on surface 4198

Minimum Curve Length is: 0.090000 for curve 3644 on surface 4198

Maximum Ratio of Adjacent Curve Lengths is: 6.748601 on surface 4198

Minimum Distance Between a Single Loop is: 0.037242 on surface 4198

Minimum Interior Angle Between Curves is: 90.000000 Degrees on surface 4198

Maximum Interior Angle Between Curves is: 90.000000 Degrees on surface 4254

Centroid of Composite surface located at: ( 0.362100 , 0.479605 , -0.276899 )

*End of Summary

Here is the meshing python script
custom_mesh_size.py (1.6 KB)

#2

Hi @thallam,
could you please provide the geometry where the script works on too.

#3

Here is the geometry file. It is surface 4196 4197 and 4198. These are the 3 surfaces in the model that have a zero area

#4

Hello @thallam,
i am sorry to say that i don’t have solution for you yet.
The surfaces with zero area are spline surfaces. They get merged with cone surfaces in your model, but unfortunately i can’t change the merge order so that the cone surface will persist.

There are quite a few bad surfaces that you can get when you do

draw surface all with area < .001
list volume in surface with area < .001 ids

grafik
grafik526×576 20.7 KB

I can get rid of the spline surfaces with

regularize volume all

or rebuilding the containing volumes. But then i get in trouble with imprinting and merging them as cubit crashes. A dev will take a look at those crashes.

Is it possible that you rebuild the problematic surfaces in your cad software?

The other thing you can do is to hardcode the surface ids into your python script to filter them out, so that your script doesn’t fail when doing the numpy.log10(surf_area).