Modify and print an stl file  

RE: Modify and print an stl file

I tried to attach the stl but was too big.    Here's a zipped version.

RE: Modify and print an stl file

Without seeing the model then we can't know for certain.  However from similar requests here in the past with geo models then I'd say no.  A model to be sliced needs to be a solid manifold mesh.  The vast majority of those types of things aren't, and from your description it doesn't sound like it is.

I suggest you go back to learning how to make a part solid in cad.  Both those programs you mention should be quite capable of that, although the only one I'm familiar with is Blender as that is my primary design tool.

If you want to attach a file for people to examine then you need to first ZIP it up.  If you don't the forum will silently just not attach it.  Also when posting its best to check if it actually was attached immediately afterwards as the forum has a VERY short post edit window.

RE: Modify and print an stl file

Heres your solidified stl.

RE: Modify and print an stl file

And here is the blend file with it in.  I took it into Blender, filed in the sides and the bottom to make it solid then extruded a little thickness. You can either cut it or sink it down to make it thinner.  It was also a VERY small size on import into blender so you might need to scale it to whatever you need to print at.  I just sort of enlarged it in blender to see what I was working with.

RE: Modify and print an stl file

Thanks for doing this.  I know about the size problem.  When I try to open your file my Blender crashes.  I will look into updating it and try again.

RE: Modify and print an stl file

I updated Blender and it works!  Your file looks good.  I will try later to export and print it with PrusaSlicer.

Thanks again.

RE: Modify and print an stl file

Neophyl,

I am new to Blender. Could you please outline the steps you used to fix this file? If this print is acceptable then, as a reward, I will probably receive more, similar files to print. If so, I would like to pass along the process to them to make my printing easier. 

RE: Modify and print an stl file

Hiya Phil from another one 🙂  Yeah far better to learn how to do something yourself.  Always encourage that.

Attaching pics on the the forum is a pain in the rear but I'll try and do a text step by step.  I'm currently running 4.1.1 on Blender.  I keep meaning to update but just haven't gotten around to it yet.  Bear that in mind as Im not sure if anything has changed between versions.  Blender is under continuous development which is both a good thing and a bad thing.

Ok first thing I did was import the stl into a new blend file - duh.  Then I scaled it up to something more reasonable to the viewport.  About 100x its size. I suspect this is because my Blender is set to work in millimetres which matches the scale that Prusa Slicer expects and the original model is in metres or centimetres.   I going to assume you know how to scale 🙂  If not then YouTube is full of various tutorials for Blender.  Another plus point for it I think.

Next was to Select edit mode on the stl and change to vertex mode so that all the individual vertices are visible.  Its a pretty dense mesh so there are a lot of verts.  
Next was to go to one of the corners and select the very corner most vertices from the bottom.  I then used extrude constrained to the Z axis to extrude another vertices downwards.  Exact distance doesnt matter at this stage, just want an extra one down and linked to the corner.  I then repeated that on all 4 corners.  This gives you 4 vertices below the original mesh but connected to the mesh at the corners.  

I then selected all 4 of them and use Fill.  That added lines between then and also adds a face to the bottom.  Now the face is not flat as the 4 vertices are not all at the same height.  Thats easy to fix though.  With th 4 verts still selected (which in effetc means the entire bottom face/rectangle is selected) you can simply type on your keyboard S>Z>0.  Thats S for scale, followed by Z for the axis you want to scale followed by 0(Zero) which is the amount you want to scale by.  This has the effect of making the z positions of the vertices the same and averages them out between all the selected.  Its the quick and easy way of flattening something in Blender.  Great for meshes you download that dont have a flat bottom too.

So now we have a flat bottom with a filled in face connected to you original mesh by 4 edges at the corners.  Unfortunately the mesh isnt manifold as the 'sides' are open.  So the slicer wont like it at all.  
Also easily fixed though as you can change to wireframe view so all the vertices are visible, orient your view along one axis by using the number 1 on your keypad.  You then drag select a selection box  carefully over the verts on one side of the object.  The idea is to select all the vertices around the open 'hole'.  Then you can use Fill to fill in the hole with a face.  Each side should have an open 'hole', so there 4 to select and 4 to use the Fill command on (Shortcut is F for Fill on a default install). 

You can then use a little Addon called the 3D-Print tool to check if the object is manifold.  If you didnt miss any verts when closing the holes it should be manifold.  The tool can also sometime fix non manifold issues but its entirely dependent on how broken the model is.  The 3d-Print tool will also analyse for other issues. 
For example your mesh reports 524288 zero faces, 12 thin faces when I scanned it after making it manifold as outlined above.  Generally though zero faces dont cause an issue when slicing, non manifold models are the biggest issue.  I suspect though that if you tried to use Prusa Slicers paint tools to colour this or even mark areas for support etc that it would have trouble.  The brush doesn't generally have access to folded faces and zero size ones.  Not a problem in this case though.

At this point if you followed along you have a printable model with a flat bottom so its just a case of changing back to Object mode to view it and then exporting the updated mesh file as a stl. 
Loading it into Prusa Slicer should give you geometry with no yellow warning triangle next to its name.  The little yellow triangle is prusa slicers indication that theres something wrong with the model.  

Now I'm sure that I've glossed over several steps, probably due to doing them without even thinking about them so if you want clarification on anything please ask.  It did only take a very few minutes to do the mesh rework.  Once you get used to HOW to select things in blender and some of the keyboard shortcuts some tasks are trivial to do timewise.  And I'm slow compared to some of the guys doing videos on youtube.  As I've only really learned and remembered the stuff I use most often.  

RE: Modify and print an stl file

Neophyl,

Wow, thanks for the detailed reply. I will try to reproduce  your steps on the original file. Blender is a steep learning curve and I expect I will discover some of those steps you may have omitted as being too obvious to mention. I’ll let you know how it turns out.