Help with CURA Problem!

[Choclit99 0]

I am attaching an STL file that is basically a solid 3D rectangular object with a cavity from the top.  When I slice it, it completely ignores the cavity and fills the entire rectangular object.  I can't figure out why CURA is doing this or how to fix it.

Opening Test 2.stl

[gr5 2,170]

It would be nice to see a screen shot.  

1) What Cad software did you use?

2) Is it manifold?  Are there surfaces on the outside and also on the inside spaced at least 1mm apart?

 

It's probably the normals which specify which is inside and which is outside of every surface.  There are 3 different ways to fix this depending on which CAD you used.

 

Alternatively you can try this:

In the upper right corner of Cura click "marketplace" and make sure you are on the "plugins" tab and install "Mesh Tools".  Then restart Cura.  Now right click on your model, choose "mesh tools" and first choose
"check mesh", then "fix model normals"

[kmanstudios 1,120]

This model cannot be fixed in its current 'object' structure. Hopefully I can explain this, so bear with me.

 

I opened the model in my 3DSMAX and ran an 'STL Check'. This is a very simple toll that can analyze the structure for many defects. This is what I found upon just starting the process:

Turquoise boxes show the errors. The blue arrow shows the top part that cannot connect to the cylindrical object. This is because the inner cylinder is a manifold object itself.

 

As you can see here, the box is proper walls with a single edge that Cura is capping trying to make it a manifold object. The obliterates the interior cylinder. The blue arrow points to the void and the purple arrow shows the separate manifold object.

 

 

The slightly shaded area is the manifold 'double wall' floating inside the box area.

 

I made a very quick model that shows how it should have been done.

I started with a box. Then made a separate chamfered cylinder and subtracted that from the box. I came out with single walls that are manifold across the entire structure. Contrasting the original model with the double walled cylinder.  This has a single wall that caps all positive surfaces and leaves the negative void to do its job (whatever that design feature is for)

 

Here I removed the top part of the box to show the contrast between the original model and the proper model.

The red edges are the open surfaces that can connect from a single wall to another single wall. The original model had a separate manifold object inside the non-manifold box.

 

This shows what the same area of close up from the side looks like in a proper set of walls: it is not a double wall....

 

So, the upshot is that the original model cannot be printed or fixed in its current shape. I do not know what package you used, but I cannot imagine any program that will not allow you to subtract one object (say the cylinder) from another (in this case the box). These are simple boolean operations that allow for this specific type of construction.

 

Feel free to ding me if I have not made anything clear. I can follow it, but that is not saying much 😆 I will be happy to try and confuse you some more 🙂 

[GregValiant 1,250]

I will take it upon myself to be the resident translator here.  After carefully going through @kmanstudios explanation, the translation is:

 

Dat model be broke.

[kmanstudios 1,120]

15 minutes ago, GregValiant said:

Dat model be broke.

🤣

[gr5 2,170]

The bearded guys have spoken.  🙂