How to « put a wall » on side of an open shape

[claudefrancois]

I tried on left part of the picture to « close » the left side of the shape with a « form » I made in 2D - this Is not satisfying and not pro.

How could I do to achieve this nicely ?

Thank you very much

[KPeter]

Hi, I would offset the inner edge with let’s say half of the wall thickness closer to the outer edge to make sure the extruded body will intersect perfectly with the existing body. Then give it a thickness and Union them together.

[claudefrancois]

I am not sure I understand - but I will try thanks

[KPeter]

Something like this

[Vencac]

That is a beautifully elegant solution!