How to separate disconnected parts?

[zapta]

Anybody knows if Simplify3D can split an STL file into disconnected parts similar to Cura and Slic3r? I want to print only one of the parts from a STL file that contains multiple parts.

I did found a command called Separate Connected Surfaces but it separates the STL into surfaces, not parts. For example with the attached STL file, the two hollow discs are split into 4 surfaces and if I try to delete the two surfaces of one disk and print the other two I get a corrupted object (a solid disc instead of hollow).

I am using S3D 3.1.0 on Mac OSX.

------------

// OpenScad script to generate the hollow discs STL file.
module hollow_disc(x, y) {
translate([x, y, 0]) {
difference() {
cylinder(d=40, h=10, center=true);
cylinder(d=36, h=6, center=true);
}
}
}

hollow_disc(0, 0);
hollow_disk(0, 50);

[dkightley]

for this example.....dead easy

Use the Separate Connected Surfaces as you have already and then either:

In the Models list, select hollow-cylinders and hollow-cylinders(2)..and delete them. Print what is left as normal

or:

In your process settings, click Select Models...and change so only hollow-cylinders and ho;;ow-cylinders(2) are selected. Save and print.

[zapta]

for this example.....dead easy

Use the Separate Connected Surfaces as you have already and then either:

In the Models list, select hollow-cylinders and hollow-cylinders(2)..and delete them. Print what is left as normal

or:

In your process settings, click Select Models...and change so only hollow-cylinders and ho;;ow-cylinders(2) are selected. Save and print.

Thanks dkightley.

Dead easy you say. Does your suggestion actually work for you ( STL is attached to my original post)?

When I try it here, S3D generates a solid disc, not hollow. You can verify it in the slicing preview mode window by moving the sliders.

[JohnOCFII]

for this example.....dead easy

Use the Separate Connected Surfaces as you have already and then either:

In the Models list, select hollow-cylinders and hollow-cylinders(2)..and delete them. Print what is left as normal


Dead easy you say. Does your suggestion actually work for you ( STL is attached to my original post)?

When I try it here, S3D generates a solid disc, not hollow. You can verify it in the slicing preview mode window by moving the sliders.

Weird. You are right. I was just writing up the detailed instructions below to show you that it worked for me, and then I realized that while I was able to successfully remove one of the two cylinders, it now printed with infill!

You can get around that by removing infill in the "Edit Process Settings" and setting infill to 0, but it will also eliminate the few layers of infill in the top and bottom of the cylinder that was in the original model.

I do not know why it behaves this way. I don't know enough about the "Separate Connected Surfaces" feature to know if this is a bug or a feature. I also don't know why it created 4 models, and that you can delete 3 of them, and still be left with what looks like a decent model.

• Import hollow_cylinders
• Select Mesh --> Separate Connected Surfaces (You should now see 4 items in the model list)
• In the Models window in the upper left of screen, select top item "hollow_cylinders" and press 'delete' on keyboard
• In the Models window in the upper left of screen, select top item "hollow_cylinders(2)" and press 'delete' on keyboard
• In the Models window in the upper left of screen, select top item "hollow_cylinders(3)" and press 'delete' on keyboard
• You should now have 1 items remaining in model list, hollow_cylinders(4)
• Press "Prepare to Print!" button, and move the preview sliders to confirm you now have a single cylinder!

You'll see that the remaining cylinder has a bottom, a top, and the cylinder sides, but the inside is

I did this on a Mac as well.

[zapta]

Hi JohnOCFII, thanks for checkin this up.

Proper separation can possibly be done with third party software. With openscad for example, I think it's possible to import the stl model and intersect it with a cube that contains only the desire part. Would be nice to have this working in S3D though, for example, a surface that represents a hole should stay with its parent surface rather than becoming an independent part.

[dorsai3d]

So the problem here is that when you separate connected surfaces, it only keeps things connected that are actually connected. In the case of a fully hollow body like this, there's no connection between the inside and outside surfaces. So when you separate, you get them all separated.

The catch is, now Simplify3D sees them as separate parts, and joins them together properly. You can get around this by selecting both remaining parts, and saving them out as one STL. Now, when you import this, you'll have one model with both surfaces that prints as desired.