Solid cant be created due to naked edges

I am trying to create a solid from a drawing of a series of ribs for an architectural model and renders. I can successfully create two network surfaces and cap the planar holes but I cannot create a solid due to naked edges. Here are some screenshots and the file in question:

Roof Model - 66m18m.3dm (335.8 KB)

Ive managed to make it work by joining the edges, however I understand this isn’t a proper fix for this issue, for technical drawings etc

This isn’t a proper fix, period. I never understood what happens internally when you force the edges to join, but you may face a lot of issues due to this “fix”. I suggest you work more accurately make sure the number of control points of the surfaces match in the problematic area and that your surfaces have the same degree.

I understand it isnt a solution. To run a 3D print for a concept model it shouldnt be an issue though. The control points do not match in the problematic area. What is the best way to fix this? I tried to build the model as accurately as possible, especially as it is symmetrical. So not sure why the control points arent symmetrical across the model

Hello - - MatchSrf for Position only, the surfaces along each long edge. Set ‘Match by closest points’ and ‘Average surface’, then Join and Cap.

Any luck?


There is a certain type of discipline to the workflow that helps a lot with downstream joining, etc. for a model like this. Here’s what I would do:

  1. Set Construction Plane in Top view to Z=0 if it’s not there already. You said it would be symmetrical about the x-y plane, so draw a curve for the boundary on one side. Use as few control points as possible to get the curve you want. Make sure the Y and Z coordinates of the ends are all zero.

  2. Set Cons Plane to y=0 in the Front view if not already there. Draw your upper and lower boundary curves as in step 1. Locate the beginning and end of each curve by end-snapping to the curve from step 1.

  3. I’m assuming you know which x value each of your section curves will lay upon and that they are planar and perpendicular to the X-axis. Create a layer for each section. Build a “stack” of actual rectangular planes in the Right view: one for each section. To do this, draw the first one at the first location in a sublayer of the first section’s layer, bigger in Y and Z than the widest dimensions of your model. Then array it along X-axis for the number of sections required at the spacing required. Move each rectangle to it’s own sublayer of it’s section layer. Then intersect all the rectangles with the 3 boundary curves. This will give you points to snap to for the ends of each section curve. Put each sublayer’s set of 3 on a sublayer of each section rectangle’s layer. This kind of layer structure is helpful in managing the construction of each section by allowing you to turn their visibility on and off individually.

  4. Starting with the widest section, turn on it’s sublayer with the others off, position your Right view Cons Plane from the section rectangle and build your half-sections by snapping to the sub plane end points created in step 3. Use as few control points as necessary to get the shape you want. Turn on the adjacent section sublayer and do the same thing, using the first section as a guide and using the same number of control points as the first section. Work your way through the rest of the sections in the same way, turning off section sublayers that get in your way.

  5. When you have all the sections, use network surface, loft or 2-rail sweep to create your surface. Experiment with each method’s options to determine what gives the best results. Mirror it about the x-y plane using the end points of the curves to define the mirror plane. Then join the two halves.

  6. The procedure I described above is the general one. Now try a different approach: Use 2-rail sweep with just the boundary curves and the middle-section curves. I think that with the right 2-rail sweep settings you will find that your form will be generated without any of the other section curves. If you were modeling a form where the section curves were not simply re-scalings of one another you would need more of them.

I hope this gives you some ideas.


Cheers for the advice. Followed all the steps for a later version of the model and it worked perfectly first time. Will follow that practice from now on.