Why does blending surfaces sometimes create surfaces 3D and not 3D solids?

kimokimo Member
edited August 2020 in 3D Design

Hello Ansys Community,

Sometimes when I blend surfaces together the resulting 3D structure is a surface and not a solid (see picture below)

The blend on the left is solid and is automatically merged with the extruded surface, but the blend on the right is still a surface and is not merged with the rest of the solid. The right side blend also had it's caps removed (first and third curve surfaces)

I tried re-splitting the faces and adjusting the blend control points (the white ones) but it did not change anything. I can't seem to understand when a surface or solid will be produced!

Any advice on what's causing this behavior would be appreciated

Thank you!


Best Answer


  • Unless you can get a fully close a surface from all the sides, you will not be able to generate a 3D solid. If there are small gaps between surfaces, then you will not be able to obtain a solid geometry.

    Are you able to copy the second surface separately into a new SCDM session and are you able to close the capped surfaces? Please let me know if you are able to get the 3D body.



  • kimokimo Member

    Hi Karthik,

    It seems that you are correct, I copy pasted the surface and tried to cap the ends with the fill tool but one of the ends isn't fitting correctly

    How do you suggest I proceed?

    Thank you

  • kimokimo Member

    So after a little bit of investigation I found that sometimes I can solve the problem by extruding the face to be blended a short distance

    The key seems to be that the blended surface does not align with one of the faces (see below)

    But this doesn't fix all cases that occur

    Sometimes the blend produces a solid but it does not align with the starting blend face (see below)

    I can merge these two solids but the interface becomes a series of small lines which are then a nightmare to mesh later on

    Is this a common problem with blending? Is there any way to avoid it?

    Thank you!

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