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I'm pretty new in the 3D printing world, and there are some doubts that have come my way and I've not been able to find anywhere.

Usually, I'm going to try to print pieces bigger than the bed of my Elegoo Mars Pro (which is 115 x 65 x 150 mm, so it's pretty small). Everywhere I try to look at this they are talking about Fused Filament Fabrication (FFF) printers, and I guess that material will make the answer to these questions to be different, that's why I'm asking here. All of these questions are focused on SLA printers.

Is there any kind of technique / slicer software to be able to print those pieces by parts?

I've read about slicers, but there seem to be a bunch of them, and some of them work best with some printers than others, and have different features but I haven't seen any that helps in this matter.

Also, I've seen the typical plane cut, but this doesn't make it easy later on to "fit" pieces. I would need some kind of female - male joint. Is there any (free) slicer that helps in that, and makes those joints to be accurate and solid?

Thank you!


I removed the "shrink size" part in the question and published it as a separate question. Also moved to a different question "gluing separate pieces" part.*

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  • $\begingroup$ @Trish yes, you're totally right! I've already done that! Thank you for your suggestion! $\endgroup$ – Unapedra Aug 19 '20 at 11:26
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With so many questions, I'll provide a suggestion for your first one, the alignment option. There's a 12 minute YouTube video showing how to use Meshmixer (free, multi-platform) to create alignment pins and holes while segmenting a model for printing large items.

Meshmixer screen capture

The process involves making the cut, keeping both sections. A pin is created and sized, then placed in one of the faces, while the other segment visibility is turned off. The pin is then triplicated, with one pin moved away for printing.

One of the two remaining pins (overlapped) is selected and is used for a Boolean subtract operation, creating a hole that is matching in size and location.

The first segment visibility is turned off, the second segment is turned on and the pin is selected again. The sequence is duplicated, creating a second, matching hole.

I didn't watch the entire video, but if it is not suggested, one should reduce the third pin size, at least the diameter, sufficiently to allow it to fit the holes created by the above process.

Note that the video has some inconsistencies from my experience. Some terms are changed from the video to the program, but should not cause problems.

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  • $\begingroup$ Thank you so much for your answer. I've already published the shrinking part into another question to keep it clearer (see edit). And that's more or less what I was looking for. I guess that the short answer is that is not possible to make parts that are very precise in terms of joints, as you run the risk of making unable to snap at all? $\endgroup$ – Unapedra Aug 19 '20 at 11:28
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    $\begingroup$ If you use a Square or hexagonal pin instead of a round one, the method described also makes the pin work as a quite effective alignment tool. Another option would be to use 2 pins. I suggest to scale the "peg" down about 0.3 mm in diameter for FDM, but on an SLA/DLP you might get away with a 0.1 mm thinner one. $\endgroup$ – Trish Aug 19 '20 at 16:50
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    $\begingroup$ The video does suggest a square or non-cylindrical peg and I've used a pair, well, a pair of pairs to ensure alignment. $\endgroup$ – fred_dot_u Aug 19 '20 at 17:36
  • $\begingroup$ Ok! I see! Yes, it seems that the square is best if you don't want the pieces to move, because even if it's shrinked or smaller (or not very precise with the joints), it will prevent it from rotating because of its squared shape. That's a good thing to know! $\endgroup$ – Unapedra Aug 19 '20 at 20:41
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I actually found it easier to export my model as a single STL file, and then to open up 3D builder. It has a tool that let's you create a flat plane, and then slice a model into pieces using it.

So long as you have a large enough surface area to glue, it shouldn't be a problem.

I tried using booleans and the peg\hole method in Blender, but it simply wasn't stable enough with complex models.

Where I have used pegs and hole I used round pegs or the simple reason that they are easier to sand down to the right size if they deform and are too tight a fit.

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  • $\begingroup$ Yeah! I actually discovered 3d Builder a few weeks ago, and since its last update it works pretty well. The only thing is that it's just splitting it (not adding any joints), so you better make sure that your print comes out 100% flat and without issues or it's going to be fun trying to make that fit! $\endgroup$ – Unapedra Jul 1 at 13:50
  • $\begingroup$ I try to place the slice plan along natural ridges on a model, for example the waist of a statue to cut it in half so that I can print the top and bottom at the same time. $\endgroup$ – Aaargh Zombies Jul 2 at 14:27

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