Joining two parallel curved surfaces

Hello, I am trying to build a large sphere with a 3D printer so it needs to be broken down into several smaller pieces that fit on the print bed and then will be glued together. I tried several different things with limited success and have finally found a method that has got me further than any other method, but now I have reached a point I cannot seem to figure out. I created two spheres, one inside the other and reversed the face of the inner one. Then I made a bunch of section cuts and exploded them so that I could isolate all the little pieces of the sphere. I will now one by one delete all of the parts to isolate each individual piece. However, once I have done that I now have two parallel curved surfaces that are not connected and I need to create a surface all around connecting the two parallel curved surfaces. Here is a picture of what it looks like.

image

Sounds like a lot of work, but now just join the dots. Turn on hidden geometry and draw edges between the vertices.

Oh my goodness, so embarrassing. Literally 4 lines and that was it, I wasted so much time trying to figure out some fancy method. Thank you so so much!

Definitely it will be tedious to create all of the little panels but connecting the two surfaces is by far the easiest part of the entire process.

2 Likes

Many of the pieces will be identical. Make one of each different piece into a component, then print as many as you need of each piece.

For example, separate but identical pieces for each ‘ring of latitude’ and angles of longitude from the equator?

Will you want pins and holes to register the pieces while you glue them together?

If so, pins on left and top, holes on right and bottom?

And think how you will support each one while it prints. You might be able to support it on one of the flat edge faces without too much overhang.

If you chose the pieces that way, I’d create one component for each latitude ring, then Rotate/Copy it around to create the sphere. When at my computer, I’ll try to draw it that way.

What size and thickness is your sphere, and what’s the maximum size of your print volume?

Here’s an example:

Dome 140mm inside radius, 150mm outside radius. Circles 12 segments per 90°. You can draw these manually, or use the SU Parametric Shapes plugin from SketchUcation plugin store, as I did.

Segmented vertically at halfway, and into 8 octants radially, you get 16 pieces per half dome, or 32 for a full sphere.

Print joining pins to fit in the dome’s bottom holes if you want a full sphere.

Dome 150mm R.skp (138.8 KB)

Two pieces shown oriented for 3D printing with a flat face down, and not too much overhang - these would probably print without support, and the larger one fits inside a print volume approx 106mm x 80mm x 107mm.

You may have to shrink the pins, and/or or enlarge the holes by around 0.5mm diameter, to allow for FDM printers printing pins oversize and holes undersize, by half the nozzle diameter.

2 Likes

You may find Split To Plane useful.

That looks so much better than what I did. The outside diameter of my sphere has to be 20.5", the inner diameter doesn’t matter, I was just adding enough thickness to allow for gluing. I did think about keying the pieces with pins and holes but I was worried it might make the printing more difficult. The max size of the printer bed is 8"x10" so it seemed like my model was going to have to be broken into about 32 pieces (16 per half).

I have never heard of Split To Plane so I just watched a video on it. That looks like it would be perfect for what I am wanting to do but unfortunately it requires Pro, which I do not have.

If you don’t care about the interior of the sphere there is a trick:
print each of the ‘half watermellon slices’ in vase mode with a thick wall setting. This way it will print in no time.
(I am saying this because I’ve done it with a sperical object that I’ve printed)
Depending on your printer it might create small artifacts near the tip but the time and material you will have saved will well worth a little cementing and sanding. (each slice will print in minutes instead of hours)
Also, you will not have to worry about pins and grooves, each slice will have a clean flat surface that you can easily glue to the next one.

Your profile states you have 2017 Pro. If that is not the case, what do you have? Please update your profile with the correct info.

Instead of printing pins and holes you can also just print holes and use little snippets of filament for allignment…
This trick can also be used for hinges.

Yup, looks like I do have 2017 Pro. Using the Parametric Shapes plugin and the Split To Plane worked great. Thank you very much to everybody.