Hi Lanren,

> how to do it in MOI?

Do you mean how to fill in that open spot? The Network command in MoI does not currently have any options for continuity along the edges, so it's not usually good to build things in a "patch by patch" method like you show there.

Probably the easiest way to finish that particular model though would be to trim the side surfaces so that you had an entire long strip of open space instead of just a small area, and then you can use Construct > Blend to fill that in with a smooth connecting surface.

The main tools currently for continuity in MoI are Fillet, Blend, and there is also a new N-Sided command in the current v3 beta, but that tends to bulge out a bit in a case like that where some sides are longer than the other sides.

If you check out some of the previous links that I posted those give some other techniques using Filleting as well.

- Michael