I'm new to 3D Printing. I've created this star from Blender3d. As far as I know, most printers require a flat bottom.

As you can see (blue line is Z-axis, red line is X-axis, green line Y-axis), the star doesn't have any flat sides or points.

enter image description here

There's a hole in the middle of the star. enter image description here

Is there a printer (brand/model) that can print this object that doesn't have any flat bottom or sides having a hole that goes through in the middle? Any workarounds to print this object?


2 Answers 2


Typical FDM desktop 3D printers might struggle with this model as it requires you to either print large overhangs and use support structure (when printed laying down), or lacks a natural flat bottom surface to get good print adhesion (when printed upright). A couple of suggestions:

  1. Some FDM printers are great at printing support, and some even allow you to print dissolvable support structure. If you find one of these, you are home safe.

  2. You could split the model in two, print those parts separately, and then glue them together afterwards. This is quite common for complex models, and allows you to print your model on even basic FDM printers. Tom's answer illustrates this well.

There are naturally other 3D printer technologies too (SLA, resin etc.), but I have no practical experience with these myself, and leave it up to others to give you a good answer regarding these.

  • 1
    $\begingroup$ If you don't like the idea of cutting the star in two, the support material is a good route. Even non-dissolvable supports will work, but would leave attach "dots" on the model. I have a dual extruder printer which uses PVA support material and the surface contact isn't flawless, but it's superior to attempting bridging out to the ends. I think most slicers will create a flat spot of some size, perhaps not as small desired. $\endgroup$
    – fred_dot_u
    Jun 13, 2016 at 0:03
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    $\begingroup$ It seems that, for this particular 'star' model, that splitting the star in half (to create a flat bottom and remove any overhangs) will be the best solution, and especially because the top and bottom will be identical. $\endgroup$ Jun 13, 2016 at 4:16
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    $\begingroup$ I would suggest to experiment with Meshmixer application and its function to auto calculate position and support pointes. This app is really great with that (while it's not perfect for sure). What is the most important - it can propose orentation which human wouldn't even think of :) Just give it a try. $\endgroup$ Jun 13, 2016 at 17:01
  • $\begingroup$ @darthpixel, that is good advice! Perhaps this model could be printed upright with some decent support pillars? $\endgroup$ Jun 13, 2016 at 18:10

The existing answer seems to suggest printing the model in the orientation as shown (e.g. with the Z-axis of the part corresponding to the Z-axis to the printer) with either support or splitting it in half.

Using supports in this way is a bad idea, because it will leave a very rough surface finish due to the geometry (and be very hard to remove, unless you want to deal with troublesome support material). The model also will have no contact with the build plate at all, making it very likely that it will detach (even when you're using support, you want a reasonable amount of surface area making contact with the build plate). You'd have to drill out the hole in the middle (since support can not be removed there).

The approach of splitting it in half and printing in this orientation isn't ideal either, because the surface finish will again be very rough due to the very gentle curves of the star. The hole in the middle will also turn out a bit deformed and flattened and require support.

Instead, for this model, a much better approach is to split it like this:

The model is split by a line passing through two "points" of the star.

The top half has no overhang at all, and the bottom half only has gentle overhangs that are easy to print without support. The surface finish will be much better compared to printing in the other orientation. Moreover, the hole can also be printed in the XY plane leaving it cleaner as well.

  • $\begingroup$ On a side note, slicing the model along this axis will also reduce the chance of the first layer lifting thereby avoiding a "seam" when you glue it together afterwards. $\endgroup$ Jun 13, 2016 at 5:08
  • $\begingroup$ Great suggestion Tom. My question is, how did you 'come to understand' this line of symmetry? Was there some type of software or just plain and simple intuition and experience? Thanks in advance. $\endgroup$ Jun 13, 2016 at 22:52
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    $\begingroup$ Just intuition. $\endgroup$ Jun 14, 2016 at 13:58
  • $\begingroup$ The split can be done easily in OpenScad. import the existing model and subtract out a large cube where the top is. rotate the other piece so the cut side is down on the print bed. Save it. Then do another one where you subtract a large box from the big side. Rotate it and save it. $\endgroup$
    – EvilTeach
    Sep 19, 2016 at 20:30

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