Which of these mesh are better for same part?

[blonjuan44 1]

Which of these mesh are better for same part? My printer told me "poor mesh" but I do not know what is good or bad, isn't a smooth surface better - but that requires less triangles, isn't more triangles more detailed but take longer to print?  I am not a 3d printer myself - I have no idea, I know basics like the 45 degree rule, I cannot ask them -  because have asked too much already, this is the last issue to solve, which is better of these two - this is a simple funnel wall part.  Do printers get a choice of how many triangles?  Couldn't the printer just change the infill type or is that locked in the .stl I give him.  I used a 3rd party designer and a 3rd party printer, I cannot just let them work it out, that is my part. Its hard to google due to other mesh definitions.

simple funnel part t01 pdf.pdf

[gr5 2,265]

So they make you slice the model and they print it?  I never heard of that before.   Usually you send them the STL and they slice it.

 

When cad exports, fewer triangles is certainly better.  So the left one is definitely better.  It will slice faster as well. Typically there is an option in the CAD that lets you set things that define how many lines to use on a curve.  Maybe it's called resolution.  I don't know what's best but I'd go no smaller than 0.1mm.

[blonjuan44 1]

14 minutes ago, gr5 said:

So they make you slice the model and they print it?  I never heard of that before.   Usually you send them the STL and they slice it.

 

When cad exports, fewer triangles is certainly better.  So the left one is definitely better.  It will slice faster as well. Typically there is an option in the CAD that lets you set things that define how many lines to use on a curve.  Maybe it's called resolution.  I don't know what's best but I'd go no smaller than 0.1mm.

Thanks.  I was told my model had "bad mesh" - but they did not explain what that means.  The attached examples were given to me by someone explaining what it is, but do not know why mine was bad - maybe I had too many rounded surfaces instead of polygonal because that makes too many smaller triangles?

[gr5 2,265]

Oh.  Your part is not manifold.  You can google that word.  non-manifold parts don't properly define something in 3d space - typically the skin has holes or there are skin passing through skin or other impossibilities to exist in real life (but possible in STL files).

 

Cad software for mechanical engineers typically are not even capable of making non-manifold models.

 

The two most common cad programs that easily make non-manifold parts is blender and sketchup.  Did you use one of those?  If so, there are fantastic tutorials on youtube of how to make your part manifold.  If you did not design the part, there are free services on the web to try to repair manifold parts.

 

There are also tricks in CURA to test if your part is manifold.  There are probably over 100 programs that can tell you if your STL is manifold.  Google about this. e.g. "how to make part manifold in blender", "web sites that repair STL mesh", "how to see if my part is manifold using cura".

[blonjuan44 1]

Thank you, I had heard of the 45 degree rule, but I never heard the concept of Manifold before, I googled and watched videos on it.