Hi bartosh, for the face in your example there I'd rebuild it by first selecting this edge shown in red here:



Then run the Extrude command and snap the point to extrude to onto this endpoint here:



That will make a surface covering an area like this:



In order to incorporate the notches you'd then use the Edit > Trim command to trim the extruded surface by these edges here:



Now you'll have a trimmed surface that matches the hole and you can use Edit > Join to join it in and make the object a solid again.

There is some more information about techniques like this in the object repair tutorial here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17

But often times problems in a particular face can be in the trimming boundaries and the underlying surface is actually ok. So instead of deleting that face like you show above it would be good to first extract that face and untrim it because that will give you the full surface and you won't have to remake that part. Then you can retrim it. That process of extract, untrim, and retrim is covered in that object repair tutorial.

At any rate, anytime you have a boundary with more than 4 edges, the technique for filling it is going to be to initially build an extended 4 sided surface and then use trims or booleans to trim away areas of it.

Hope that helps - if you have another example that you have a question about please also post the 3DM file so I can use your file to help illustrate what to do.

- Michael

Thanks, Michael.

I`ve already done it (by network with using 4 edges patches) but your last method is a lot faster :)

So process of rebuilding flat faces based on boundary edges is:

3 or 4 edges - select edges and click network button
more than 4 edges (flat) - select edges, click planar button, fire script: "ShrinkTrimmedSrf" (why there is no button for that?)
more than 4 edges (curved edges - flat face) - select longest curved edge and extrude it, trim rest and cut out

Thank you very much.

Hi bartosh,

re:
> 3 or 4 edges - select edges and click network button
> more than 4 edges (flat) - select edges, click planar button, fire script: "ShrinkTrimmedSrf" (why there is no button for that?)
> more than 4 edges (curved edges - flat face) - select longest curved edge and extrude it, trim rest and cut out

It's usually best to focus more on the shape of the surface than the number of edges. If it's all on a single plane it's better to use Construct > Planar on that for all numbers of edges, including for 1,2,3, or 4 edges. That makes a simple plane for the underlying surface which can then get special case handling for intersection calculations.

Network is more of a last resort method, if nothing like Planar, Extrude, Revolve are a match. If you use Network on flat curves it will make a surface there but it won't be a simple 4 corner point plane and so it won't be able to get special case intersections with it.

re: ShrinkTrimmedSrf, there isn't any button set up for that because it's not generally very useful, if you have a flat area just use Construct > Planar and don't use ShrinkTrimmedSrf afterwards unless you have some special situation like you want to modify the surface control points. It's normal for an underlying surface to extend out a ways, it's not something you would normally need to try and avoid.

- Michael

Hello,

This model can be constructed very quickly using Extrude and Boolean tools. Unless I'm missing something there should be no need for Network commands. Can you share the model or dimensions?