Stl models I make are always sliced weird

So I've been using Blender to just make some little doodads to get used to the whole process, but I'm noticing that whenever I go to print slic3r always complains about "overlapping or self-intersecting facets" and the G-code is all wrong. I'm not making anything too complex, I think: I made a circle, extruded it, then extruded it again to make a plastic washer for the end of my spool spindle, and the lines it makes don't even try to resemble a circle.
I've been uploading them to netfabb cloud to be fixed, so it's not like there isn't a workaround, I was just wondering if anyone knew if this was an issue with Blender and exporting with something else might work better, or a general issue with any modelling software, or if there might be something I'm missing that would actually solve the problem once and for all.

 

Print3D plugin to blender is your friend (File -> User Preferences -> Addons tab -> Mesh category then click the Checkbox next to Mesh: 3D Print Toolbox). Sadly, it is the type of friend that doesn't really tell you in plain English you are screwing up. Just dumps technobabble at you assuming you know what it means.

http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Modeling/PrintToolbox

After enabling Print3d you should be able to go into edit mode, hit "T" to get to the mesh tools set (normally on the left side) scroll down to Print3D, ensure in the window with your mesh you hit "A" to select the model. And hit "Check all" then scroll down you'll see "Intersecting Faces" button you can click, and it will go into Faces mode and will show you what faces it thinks is wrong. Most of the time it is either two faces that are jammed together to tightly (which normally isn't an issue). Or extra bad geometry inside the model that is causing the slicer not to know which face to slice on.

It is kinda hit-and-miss as to what of the output items will cause you major grief, and what is just whiny. I've found the thinner the part and more critical the warnings are. And the more likely you should respect them.

You may want to skim: http://forums.robo3dprinter.com/index.php?threads/blender-object-size-vs-repetier-object-size.988/ where I talk about what the correct settings are in Blender for making the model the right size on export as well.

Other things that cause issues on export:
- unapplied object modifiers
- inside-out normals (you can use "Recalculate" in the mesh tool set)
- Unapplied scaling/rotation (Ctrl-A will bring up the menu to apply them)

Blender is a wonderful tool, but it's sharp enough to take limbs off if your not use to it. =(

 

I will keep these in mind. Debian has an old copy of Blender in the repo without the 3D Print tools. I'm upgrading to Arch soon, so I'll give that a try.
I'm out of filament anyway. Not going to have more for a couple weeks.
Thanks for the tips!

 

There are options in CURA to deal with that kind of problem
This is because who ever made the model wasnt thinking about printing issues.
Open Expert settings in CURA and check/uncheck boxes under Fix Horrible.
See layer viewport update instantly with results.

Sometimes i have to go there to print my own things.

This takes place because:
2 boxes 10x10 are put together making 10x20. Now you have walls touching each other creating problems.
Solution: Remove touching walls and weld points together to make it one object.
You cannot merge them onto 1 object and call it good, wall is still there even if its merged (depending on the way you merge)

 

Might wanna upload your blender file somewhere so we can take a look at it. I've recently started learning blender myself and self-intersecting faces usually means a face going through another face without having vertices on the face its going through.

 

Please dont send blend files, they are incapable with anything other then blender.
Export universal OBJ
OBJ is not STL and does not get screwed up like STL does

 

I use a program called Cinema 4D.

It recommends to reverse normals when exporting to STL

When modelling try to use primitive and extrude to shape. Try not to edit single points since overlapping cans occurred creating an impossible face, let alone a face that will confuse the software.

If it doesn't slice, try different orientations in the software. Also try scaling it up or down and see if it slices.

If your still having problems then I suggest remodelling or try a different software that it a true 3D program for animations.


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CURA does not care if normals are reversed or not. When you export to STL, model is broken down into faces, so it does not care about which way its facing as long as its not an empty space it gets treated as a boundary of something.

When you import STL file into your 3d program, 1st thing u want to do is to weld all vertices at lowest possible threshold to avoid welding small pieces together.

3DSmax pops dialog to weld, but its a bad idea to weld during IMPORT, do it only when model is already imported.

 

Watch this. Hope this helps

 

So reversing normals is important. Since most 3d programs have the faces looking inward, you must make them facing outward.

He also covered the vertex overlapping issues. Good video.


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