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Radio button “Face” or “Volume” specifies which type of entity to select  for reorientation.

To illustrate its work for “Volume” follow the scenario:

 (deleted for brevity) 

Regards,

 

Grigory

 


Hello Grigory,

Wonderful explanation!  Thank you.  Now I understand clearly the difference between the two.  Very much appreciate your help...

Regards,
JMB
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How to orient normals outward or inward

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  • How to orient normals outward or inward

    Posted by JMB at January 06. 2007
    Hello,

    How can one orient the normals of a 2D/3D mesh all in one direction?  I see the Modifications -> Orientation -> Face/Volume, but I see no option to specify the direction.  Which way will they be oriented if I click the "Ok" button?

    JMB
    • Re: How to orient normals outward or inward

      Posted by Grigory Zhivotovsky at January 15. 2007
      JMB wrote:
      Hello,

      How can one orient the normals of a 2D/3D mesh all in one direction?  I see the Modifications -> Orientation -> Face/Volume, but I see no option to specify the direction.  Which way will they be oriented if I click the "Ok" button?

      JMB

      Hello,

      It is very important to have the same orientation of elements. Different orientation can result in errors when you apply distributed load depending on normal direction.  To check orientation in GUI look at faces color.  Colors of front face and back face are defined in preferences Mesh – Mesh.

       

      To change orientation use the following scenario:

       

      1. Click menu  Modifications -> Orientation.

         

      2. Activate radio button Face or Volume depending on type of elements you want to modify.

         

      3. Select entities you want to modify.

         

      4. Click Add button (list of selected entities appears in dialog box)
      5. Click OK or Apply  button (orientation and correspondingly color will be changed)
      Best Regards, 

      Grigory


      • Re: How to orient normals outward or inward

        Posted by JMB at January 15. 2007
        Grigory Zhivotovsky wrote:
        JMB wrote:
        Hello,

        How can one orient the normals of a 2D/3D mesh all in one direction?  I see the Modifications -> Orientation -> Face/Volume, but I see no option to specify the direction.  Which way will they be oriented if I click the "Ok" button?

        JMB

        Hello,

        It is very important to have the same orientation of elements. Different orientation can result in errors when you apply distributed load depending on normal direction.  To check orientation in GUI look at faces color.  Colors of front face and back face are defined in preferences Mesh – Mesh.

         
        To change orientation use the following scenario:

        1.  Click menu  Modifications -> Orientation.
        2. Activate radio button Face or Volume depending on type of elements you want to modify. 
        3. Select entities you want to modify.
        4. Click Add button (list of selected entities appears in dialog box)
        5. Click OK or Apply  button (orientation and correspondingly color will be changed)
        Best Regards, 

        Grigory



        Hello Grigory,

        Thank you for your detailed reply and explanation.  I was aware of the importance of uniform orientation of elements, however I have another question.  In the Modifications -> Modifications of orientation, there is a choice for Face or for Volume.  What does the volume option do?  I tried it on a tetrahedral mesh and it seems to make no difference to the color of the faces.  So far I am not aware of an FEA pre-processor changing the inward or outward pointing of normals for any 3D elements.  I have known them to always point outwards.  Am I mis-understanding or not understanding what Salome 3.2.2 does?

        Regards
        JMB
        • Re: How to orient normals outward or inward

          Posted by Grigory Zhivotovsky at January 15. 2007

          Hello,

          Radio button “Face” or “Volume” specifies which type of entity to select for reorientation.

           

          To illustrate its work for “Volume” follow the scenario:

           

          1. create box in GEOM

             

          2. create mesh in SMESH to mesh box with algorithms Wire discretization, Quadrangle mapping, Hexahedron (i,j,k) and hypothesis Quadrangle preferences, Nb segments=1 to have mesh containing 1 hexa and 6 faces.

             

          3. select mesh – popup in VTK viewer – Display entity – Face to hide faces

             

          4.   Modifications -> Orientation.

             

          5.  Activate radio button  Volume.

             

          6. Select Volume 19  Click Add button

             

          7.   Click OK 

             

          The colors of hexa faces are changed

           

           

          1. select mesh – popup in VTK viewer – Display entity – Face to show faces

             

          2. select mesh – popup in VTK viewer – Display mode – Shrink

             

           

          You will see that faces and hexa faces have different color.

           

          In TUI we have

           

          def ChangeOrientation(theShape)

           

          the shape can be face or volume

           

          Regards,

          Grigory

          • Re: How to orient normals outward or inward

            Posted by JMB at January 15. 2007
            Grigory Zhivotovsky wrote:
> <p>Hello,<