Having trouble with being able to slice a 3d scan into a printable stl file.

[agoodnight 0]

Modeling a grate, from a 3d scan. I popped it into Blender to clean it up, but then when I put it into Ultimaker the walls are not there when I slice the model.

 

Ornate_AirGrate.stl

Edited May 2, 2023 by agoodnight

[gr5 2,210]

Your model is pretty bad.  Sorry to say.  When you scanned it you needed to scan the underside as well.

 

As far as I can tell the walls are infinitely thin in most places.  So Cura is like - oh - infinitely thin - okay that just means zero plastic.  Done.

 

So the model needs a lot more work in blender or other software.  Blender is designed for computer graphics where you can have infinitely thing objects and they look pretty good as long as you don't go around to the back side.  In 3d printing the models have to be solid.

 

So some CAD software like design spark mechanical, autodesk, and hundreds of others only let you create "real" 3d objects.

 

Other CAD software like blender and sketchup are geared towards computer graphics and will let you create non printable 3d scenes that may look great but aren't printable.

 

There are lots of guides on youtube for how to fix your blender file to be printable.

 

 

[agoodnight 0]

11 hours ago, gr5 said:

Your model is pretty bad.  Sorry to say.  When you scanned it you needed to scan the underside as well.

 

As far as I can tell the walls are infinitely thin in most places.  So Cura is like - oh - infinitely thin - okay that just means zero plastic.  Done.

 

So the model needs a lot more work in blender or other software.  Blender is designed for computer graphics where you can have infinitely thing objects and they look pretty good as long as you don't go around to the back side.  In 3d printing the models have to be solid.

 

So some CAD software like design spark mechanical, autodesk, and hundreds of others only let you create "real" 3d objects.

 

Other CAD software like blender and sketchup are geared towards computer graphics and will let you create non printable 3d scenes that may look great but aren't printable.

 

There are lots of guides on youtube for how to fix your blender file to be printable.

 

Is there any way to fix my model without having to model the entire thing by hand, it is a 3d scan of an object that needs to be accurate.

[gr5 2,210]

Your scan can't be very accurate at least out at the edges as the actual grate is much thicker than a sheet of paper, right?  Whereas your scan appears to be mostly thinner than a sheet of paper.

 

Did you scan the bottom of the grate as well?

 

I have only used blender a tiny bit but I seem to remember there is a function to thicken everything.  But that will change your accuracy. 

 

Maybe @GregValiant has some ideas?  He's pretty good at fixing models but if he doesn't know which dimensions need to be accurate he'll have to guess.  I mean is the top scan accurate but the bottom surfaces are all just a guess?  That's what it looks like to me.  It looks like maybe you only scanned the top of the part and the scan software just assumed it *was* infinitely thin.

[GregValiant 1,330]

Hello from sunny Florida.

Scanning can lead to very accurate results but the point cloud must be interpreted correctly in the translation software.  20 years ago the forensic engineering firm I worked for used Rhino3D.  It was not cheap but did provide excellent results.  We were scanning wrecked cars so there was no printing involved but the scans were amazingly accurate.

 

As @gr5 mentions this scan has serious issues as far as printing goes.  After repairing the model in MS 3D Builder I can still see right inside the shell.  Open seams like that make it impossible for Cura to slice it as Cura can't tell the inside from the outside of the model.  What you end up with is a shell that is infinitely thin and does not enclose a volume.  I tried some things to fix this but I didn't have any luck.  This seems like a translation software issue when going from the point cloud to a model.

 

Your STL file can be translated into a DXF file and then can be modeled around that in CAD.  It's basicly a rectangle with a flange and with some fancy stuff inside.

The rectangle would take a couple of minutes.  The other parts would take a while longer but there are really only 4 pieces to model.  The rest would be copies.  There are the 4 corner pieces, 4 mid pieces, the center piece, and the 4 knots that join the mid pieces to the center ring.

 

I'll attach a DXF file here.  I don't know if it will be any use to you but I made it up so here it is.  It is at least a start for modeling in CAD as all the dimensions are going to be really close to your prototype part.  Time wise it's probably faster to just model it up than fooling around forever trying to get the scan to work.

 

Sorry I couldn't be more helpful, but that's what I see here.

 

 

MS3DB_Repaired_AirGrate.zip