Weird gap in models when trying to print in 2 colors?

[Flockmaster 0]

Hello, I'm using Ultimaker Cura 3.6, and for some reason when I combine two models (after setting them to different print cores), it leaves a big gap in the model that I can't seem to get rid of. I don't really know how to describe it, so hopefully, pictures help. I also included the project file

 

The first one is of the solid view, and what the model _should_ look like, the second is the line view. 

Mothman.3mf

[gr5 2,210]

It's a bad model.

 

I looked at the model and sliced it and see the same gap.  If you look at the model in xray view it has tons of red spots.  That's the problem.  The model is not "manifold".  It is not a single solid model.  Did you make this model?  Lots of cad software can convert models with overlapping volumes into a single solid volume (or 2 volumes in your case - one for the cape).

 

Or you could try fixing the model in netfab.  netfabb free repair service is here (you have to create a free acocunt first):
https://service.netfabb.com/login.php

 

Although I don't know if netfab works on formats other than STL.  You could split your 3mf into 2 STL files and fix each one separately.

 

[Flockmaster 0]

I did make the model myself, and I should clarify that it prints perfectly fine when I have it as a single model in 1 color. It's only when I split it into separate parts in meshmixer to set different print cores that it doesn't work. I could be, and honestly probably am, trying to get it to print in 2 colors completely wrong. From what I understand, to get something to print in 2 colors you have to split the model, load both, set them to different extruders then merge models, right?

[gr5 2,210]

I really don't think it's related to the "2 color" thing.  Did you see all those red dots in xray view?  That's a hint probably.

 

Can you union all the overlapping volumes in meshmixer?  For example if you create 2 spheres and overlap them there should be a way to remove the internal walls of the 2 spheres.  Some kind of union feature or "make manifold" or something.  I don't know meshmixer very well.

 

What happens if you try to slice just one of the two colors.  In other words just load the cape/wings and see if that has the gap.  Then just load the rest of mothman and see if it has a gap.  If it works fine separately but not together then maybe you are right.

[Flockmaster 0]

Ah, thank you, I see what I did wrong. When I split the models, I didnt realize both individually had to be solid objects, I'd figured since they worked before I split them, it would still work when I merged them again in cura. All I had to do was make both objects solid in meshmixer, and that seems to have fixed the issue