# Meshing areas, complex geometry

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• Last Post 02 August 2018
• Topic Is Solved
joepa_2017 posted this 31 July 2018

I have run into the following error:

"Unable to mesh area 1 because of shape problems.  It may help to change element size on edges of area."

I would like to know if there is a way in APDL to change element size on edges of area.  I assume this would mean that the mesh would be much more fine at the edge of an area while interior elements may not be so refined.  However, I don't know how to implement this, aside from refining the mesh along lines after creating an initial mesh.

SandeepMedikonda posted this 31 July 2018

Hello,

Mesh Sizing on the command line or input file includes the following commands:

• Use ESIZE to define default global mesh size applicable to regions where local mesh size controls have not been defined
• Use KESIZE, LESIZE, AESIZE to assign local element size at keypoints, on lines and areas, respectively
• Use EREFINE, NREFINE, KREFINE, LREFINE, AREFINE to refine existing meshes at elements, nodes, keypoints, lines, and areas respectively
• Use KCLEAR, LCLEAR, ACLEAR, VCLEAR to clear existing meshes at keypoints, lines, areas, and volumes

So, let's say you want to gradual size transition on let's say area 6 in your model:

`ESIZE,0.4 ! GLOBAL MESH SIZE = 0.4ASEL,S,AREA,,6 ! SELECT AREA #6ALLSEL,BELOW,AREA ! SELECT ALL ENTITIES USED BY AREA #6KESIZE,ALL,0.1 ! AREA #6 CORNER KEYPOINT MESH SIZE = 0.1AESIZE,6,0.1 ! AREA #4 MESH SIZE = 0.1VMES,ALL ! MESH ALL CURRENTLY SELECTED VOLUMES`

You can find some more examples here.

Hope this helps?

Regards,

Sandeep

joepa_2017 posted this 01 August 2018

Will this make all elements on Area 6 have equal size?  That is, will all of the elements in Area 6 have a maximum size of 0.1?  I would like to have a very fine mesh at one boundary of the area, for example, and then let the mesh become more coarse moving away from that boundary.

SandeepMedikonda posted this 01 August 2018

Yes, this would make the elements on area 6 have a smaller size i.e, 0.1 and gradually grow to 0.4 as we move away. You can always do this with lines if you need just the boundary.

joepa_2017 posted this 02 August 2018

Cool, I see that this process works for gradually changing the mesh size, thank you!