Fill a hole in a mesh of the size of a single triangle

Good morning all,

I have a mesh (triangular type : STL file) which has a hole of the size of a single triangle.
I filled this hole with the pencil tool. This works perfectly as i can’t see no longer behind the triangle
but the outline of this triangle still appears even when I apply shading on all the model.

How to proceed to no longer see this triangle?
Thank you in advance.

Marc

you can hide the lines, a short cut method is to use the eraser with shift

If the triangle is part of a continuous surface, smoothing (erase+ctrl) is better

I have selectionned the triangle with right clic > Hide but nothing happens.

How to do for have the triangle as part of the rest of the model ?

Attach the model so we can give real advice.

Impossible to attach the model as too big : > 1.000.000 triangles …

The new triangular face is reversed.
Select it > context-menu > Reverse…
Erase+Ctrl to smooth its edges…

Thank you.
I have a look.
As my model is very big, this take time (> 1.000.000 triangles …).
Regards,
Marc