Hex Mesh error not multi-surface or multi-curve

Valued Contributor
Valued Contributor

I'm trying to hex mesh a fitting.   I had it working, but at some point it became part of my mid-surface, non-manifold add geometry.   I copied the surfaces over, but then it gives me this error:

 

Skipping Solid 1059. Only true solids can be meshed, not multi-surface or multi-curve solids.

 

I have tried recreating the solids, reslicing, solid stitching, exploding/restitching.   Any other ideas what I can try?  Not sure I understand the error.

 

Thanks

5 REPLIES 5

Re: Hex Mesh error not multi-surface or multi-curve

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear AllTrans,

The error tells you that only genuine solids can be HEX meshed, do not try to HEX mesh nonManifold bodies or a body that seems to be a solid but is a collection of surfaces, skin surfaces, OK?.

You can use command GEOMETRY > SOLID > STITCH and select all the skin surfaces and if all surfaces are perfectly closed forming a closed volume (not GAPS exist, use default tolerance) then FEMAP will join all surfaces together and will create a genuine solid body for sure!!.

If not success please post your FEMAP model and we will take a look to it!.

Best regards,
Blas.

 

PD

I trick to understand if you have a solid genuine body, or a body that is a collections of surfaces (ie, a SHEET BODY) or or a nonmanifold body (ie, GENERAL BODY ADD) is to take a look to the icon of every entity under GEOMETRY in the MODEL INFO tree, see:

GENERAL-BODY-ADD.png

 

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Hex Mesh error not multi-surface or multi-curve

Siemens Phenom Siemens Phenom
Siemens Phenom

Sounds like you did a Non-Manifold Add of all geometry, and got your mid-surfaces added back into their original solids.  To recover the real solid portions, use Geometry - Surface - Recover Manifold Geometry, you should get back the original solids, which you will be able to size for Hex Meshing, and then Hex Mesh.

 

Mark.

Re: Hex Mesh error not multi-surface or multi-curve

Valued Contributor
Valued Contributor

I managed to recreate the geometry from scratch and the mesh worked.   That is unhelpful if I have anything really complex.   The nice thing about Femap is there is usually a work around.   However, I would still like to understand the issue and if there is a better way to go about it to save time.

 

I attached a portion of the model where you can see where it worked and where it does not.  I have played with the stitching and the recover manifold geometry, but neither one seems to do anything.  

 

Thanks

Highlighted

Re: Hex Mesh error not multi-surface or multi-curve

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello!,

The MODEL INFO TREE tells you the type of entities you have, you need to learn to differentiate between pure solids an surfaces. To create a solid you can use the command STITCH, but is critical not to have "repeated" surfaces, in this case the command simply joint a collection of surfaces, but not create a pure solid.

Use MODIFY > COLOR > SOLID > RANDOM, this way you can understand the type of geometry you have in your model.

surfaces.png

 

I am able to create a genuine solid after performing the following sequence of commands:

  1. GEOMETRY > SOLID > EXPLODE
  2. GEOMETRY > SOLID > CLEANUP
  3. and finally GEOMETRY > SOLID > STITCH using the default tolerance

This is the final result with a body:

surfaces2.png

Best regards,
Blas.

 

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Hex Mesh error not multi-surface or multi-curve

Valued Contributor
Valued Contributor

Thanks Blas!  Good explanation.   I always thought Femap treated solids and surfaces as bodies, but did not notice how it knew it was a solid.

 

At one point I did a manifold add where the solid was lost and it added the duplicate surfaces.   It is slightly irritating that I have to re-split the solid to get it to work, but it does work.

 

Thanks again.