How to make my hull solid??

I would like to create a solid object (similar to a torus, but tweaked) out of several closed nurbs curves.
I took the surface->nurbs circles as a starting point. Then joined them and pressed “F” to create the surface/hull. Screenshot attached

I need it to be a completely full solid now (solidifying the hull is not good enough, because I guess there will always be a non-solid interior (inner hole) left, which is a problem with 3D printing. I attached a screenshot showing this.), to be able to perform a few (simple) solid operations on it, like putting cylindrical holes into the body (the cylindrical holes fulfill a mechanical task - an additional reason for needing the full solid: otherwise the holes are not strong enough). How can I close (“cap”) the ends of my “torus” now, in a way so solid operations can be performed on it?

Many thanks for your help!


torus2.blend (377 KB)

try to convert the nurbs in polygons with ALT + C then go in edit mode and select the edge that you want to fill and use ALT+F this close the cap, with this you lost the curve information but you can close the torus.

Many thanks! Capping the ends worked wonderfully with your info!! (screenshot attached).
(I selected all end-vertices and aplied Alt+F,which filled the hole).

BUT, no success applying a boolean difference between “torus” and cylinder so far (I want to cut the cylinder out of the “torus”). Sample blender file attached…
(Blender seems to still not define the “torus” as a complete closed volume…).


torus5.blend (376 KB)

at the moment i can’t dowload i’ll check the blend file this afternoon.

what kind of operation you have to do? intersection, difference or adding??

Id like to apply a boolean “difference”, cutting the cylinder shape out of the “torus”.
I guess my “torus” is still not considered “solid” by Blender.

Going the other way round, applying the “torus” to the cylinder works…I can “difference” and “intersect” it from the cylinder.

In your blend you haven’t given the torus a boolean modifier to cut out the cylinder. Try the different boolean methods to give the effect you want, then apply it. You can then delete the cylinder.

Here is a screenshot showing what happens. When I look inside the “torus”, you can see that there is a union between the 2. (I applied “difference”), and Blender seems to define the torus still as surface, not solid.

(What I want is cutting out the cylinder of the “torus”).


I found out I could do this by inserting and modifying a NURBS torus.
But it is a bout 100 times more work, if not almost impossible to do
than first defining the shapes with NURBS curves and then joining/skinning(/making them solid). (Dragging the NURBS torus vertices to where I want them is extremely much and annoying work).

I found out what the problem was: all face normals were pointing inwards. After flipping them it works perfectly :slight_smile: