When you do a boolean operation, there are no new surface points added, instead "trimming curves" get added to the surface. There is some explanation of that here which may help illustrate it better.

Right now MoI is not generally focused so much on surface control point manipulation... Although there is some basic functionality to do it, there isn't currently a way in MoI to insert new points right in the middle of the surface.

But there are a variety of other strategies that can be used instead - the initial surface can be created with control points in the areas you need right from the beginning, using Extrude with the "Set path" option (see http://moi3d.com/forum/index.php?webtag=MOI&msg=817.4 for an example).

Or a more typical method would be to create several curves that have the shape you are looking for and use a surface creation command like Loft or Sweep to build the surface you want directly, instead of trying to squish some other surface into the surface you want.

Also it tends to be more common to add in smaller details by booleaning in a small assembly in the area you want to add detail in, rather than trying to manipulate one single big surface to have detail in a small area. You can use the Fillet command to round off the corners of where your new module meets the larger surface to give it a smooth appearance.


It is hard to give you much more specific advice, because I just can't quite tell what type of thing you are trying to build from your current description and screenshot, sorry! If you can post a sketch or something that would explain it more, that would be a big help. I especially don't understand how you want the slits on the surface to be arranged.

You can't generally cut a surface with a single line that is totally inside the surface, to boolean an object with a line, the line needs to divide the surface into 2 pieces.

If you want to cut a small opening into a surface, to use a boolean you would normally create a closed curve to use as the cutting object. It can be squished down to be pretty thin and narrow, but it still should form a closed loop instead of a completely collapsed slit like a single line.

- Michael