Input Mesh is self-intersected

Altair Forum User

Dear all,

 

I am a beginner in Hypermesh and I wish to convert a 2d surface mesh to a 3d solid mesh. My model consists of a small part of the mandible and is complicated. I have tried to refine the meshes and solved the free-edges problem which appear to be the first problem I faced when I tried to convert the surface mesh to a solid 3d mesh. But now, I faced another error : 'Input Mesh is self-intersected'. 'Boundary recovery: failed sub grid recovery...'. 

 

I chose the option:

1) Smooth Pyramid

2) Fix comp boundaries

3) update input shells

4) mesh to current comp

 

I have spent months trying to mesh this model. It would be great if someone can lend a helping hand to me!!! Thanks in advance.

 

Cheers,

Mushi

tinh

hi,

Check Tools/Intersection 

Check F10/ connectivity-duplicate

if boundary (2d elems) is complex, you should check quality also to ensure that 2d mesh has no problem before generating solid elems

Altair Forum User

Hi Tinh,

 

Thanks a lot for your help. Really appreciate it!!!

 

1) Tools/Intersection. I am sorry but I cannot find the option (Intersection) under Tools menu. Is it under Tool > Penetration > Check elements? If that is correct, I did that and it stated no intersections.

 

2) Check Elements > Connectivity-duplicate. I did that and it stated 0 elements were found with connectivity problem and 0 duplicate elements

 

3) How can I check the quality to ensure that 2d mesh has no problem? I always go to Mesh > Check > Elements > Quality Index. Is that correct? When you said 2d mesh has no problem, did you mean by 0% failed? Because I did the Quality Index step, and it stated 13,3% failed. /emoticons/default_sad.png' alt=':(' srcset='/emoticons/sad@2x.png 2x' width='20' height='20'>

 

Best,

Mushi

tinh

hi,

you are right.

i mean 2d mesh should have no strange elements (bad aspect, skew, angle), not need to 0% failed

did you activate 'self intersection' in penetration panel?

choose 'intersection and penetration'

and set uniform thickness 1.0 or more (depend on meshsize) to detect thin feature

sometimes if 2d elems too closed to each other (like a thin wall), tetra mesh will have problem (please check it with pyramid)

Altair Forum User

Hi Tinh,

 

Thanks a lot for your help again.

 

1) I activated the 'self intersection' option and set the uniform thickness 2.0 and found a few areas which have penetration. After I confirmed I do not have intersection, penetration and free edges, I tried to tetra-meshed them using the pyramid option but still it showed input mesh is self-intersected.

 

2) Next, I remeshed the whole part as tria elements then tetra-meshed the part again. It worked this time. Now my 2D surface mesh has turned into a 3d solid mesh. Do you have any idea why it does not worked for mix elements but worked for tria elements?

 

Thanks again and hope you have a nice day.

 

Best,

Mushi

tinh

Hi Mushi

I've not ever experienced by this issue because i do not use pyramid elems

my models just need tetra, hexa/penta

i don't know how meshing progress, but certainly that tria elems are more flexible than quad/mix when generate 3d mesh 

Altair Forum User

Hi Tinh,

 

Thanks again for your reply. You helped me a lot!!! I really appreciate your help!!

 

Cheers,

Mushi