Help with modeling a guide

I would like to generate a brass guide that would go on a hinged box top. I have included an image of what I am trying to do. I started by creating two concentric circles and then put two circles inside that those for the ends. I then joined all of the curves together and then removed all of the vertices that were outside my object. Once that was completed I did a similar operation to make the middle hole (but it is not a hole yet). I have all of the verticies joined into a single object. I can not figure out how to cut out these holes from the larger object. Can somebody give me a hand and point me in the correct direction? I have also included a blend file with my progress so far.

I am using Blender 2.66.1 (r55078) on Win 7 x64.


Guide.blend (496 KB)

No need to complicate things that much. It’s hard to work with that many vertices.
2D curve would be very nice to work with, adding another spline inside one makes a hole. But you could do that with mesh too

Starting from top:

  • A plane
  • Right edge selected, 3D cursor moved up, alt+R to spin. Angle -90°, 9 steps. You could also use proportional editing tool (hotkey O) to make the shape asymmetrical if needed before continuing.
  • Added loop cuts (ctrl+R)
  • Selected inner faces and inset (I) those
  • Deleted inner faces, added subdivision surfaces modifier with level 2 subdivisions (ctrl+2). Also added solidify modifier to create thickness but that should be on top of the subsurf modifier and not at the bottom like in the screenshot.

Thanks for the reply. I followed your example to generate the arced component of the guide and it worked great so far. I wanted to add a curved end to both ends so I just created a fan filled circle mesh and positioned it at the appropriate spot. I then selected both meshes and joined them with Alt+J. I then entered “Edit Mode” and deleted all of the vertices of the new circle mesh that were overlapping the arced component. I really want this to be clean. I notice two problems right now…

1: When viewing in object mode there is some sort of a boarder visible between the half circle and then arc component. I assume that is because there is an edge there but the other edges are not visible… Why is this? (I do have wireframe turned on for the object, when I turn that off the line disappears)

2: I thought that “Remesh” would be very helpful here, but, when I select it as a modifier, the object just disappears. Why is this?

I am sure that all of these things are happening because I am having a basic lack of understanding in mesh editing. I learned a lot from your response above and I look forward to learning and understanding more. I have included images here of what is going on. I have also included the blend file for reference. Thanks for any further help.

untitled.blend (456 KB)

It’s because that added circle is not connected. You would have to add edge loops to your circle to get more vertices and merge those with the main mesh.

If that dotted (active) face in your screenshot were connected, it would be an ngon (a face with more than 4 vertices - 5 in this case) and that’s a no no.

The thing is, with subdivision surface modifier (subsurf for short) you don’t need to use that much geometry which can be a pain to work with. Sure, if you know you need to keep the polygon (face) count at minimum, working without subsurf could be justified.
Subdivision surface modifier subdivides faces that you edit, creating new geometry based on that. The advantage being that you don’t have to deal with a lot of geometry, making things faster, and you can decide how much detail is needed just by adjusting the subdivision level or remove it altogether. Smooth shading takes care of the rest.

Top: mesh you are editing
Bottom: subdivision surface modifier result after level 2 subdivisions.

With subsurf, total number of faces = face_count4^level, for quad faces. So if you are dealing with 1 quad face (a plane primitive), subsurf makes it 16 for you with level 2 subdivisions (14^2 = 16), while you only deal with one.

I can not figure out how to cut out these holes from the larger object.

The method you were using is fine to make a hole. But hole will be made so long as curve is set to 2D. Don’t turn it in to mesh before having the hole there.

I make the guide this way though. Just create circle with hole, place it at the both ends, manipulate the vertices to profile, and then use [Ctrl] mouse select to string out the guide between them. Add loop as needed: