How do I stop parts being filled in that should be open?

[medicalmodeller 5]

I have a model of a boat. In the mid part of the model, there is a recess which is the cockpit where the wheel goes. On the view in Cura, the cockpit is clearly seen (arrowed). I have set Cura to 0% fill but the model comes out with the cockpit covered over with a layer of PLA. I have taken the layer off and the cockpit structure is not there . I have also printed with 20% fill and the end result it the same.

Can someone help me get the print to look like the representation on Cura?

Thanks

MedicalModeller

 

[Dim3nsioneer 557]

Open the expert settings and disable any 'fix horrible' options... you may check the result before printing with the layer view in Cura (icon on the top left). You may also check the integrity of the model with the x-ray view. If anything is shown in red there then the model has a defect.

 

[medicalmodeller 5]

Thanks. You were right that one of the fix horrible options was selected

When I look at the xray view - there is a lot of red. What is a "defect" in this situation? Is it a void that might be intentional?

MM

 

[valcrow 145]

It looks like you have a lot of mesh issues. Paticularly, it looks like you mirrored your model, and didn't flip the faces before welding the center axis.

Or there are duplicate faces. This will usually cause unpredictable slicing patterns in cura & others. "fix horrible A" already fixes some of these issues, but since you need to turn it off, you may get some other unpredictable slices like randomly filled in layers.

I would clean up the model as a solution.

 

[medicalmodeller 5]

I have tried to print without any "fix horrible" checked and the print failed after one hour. The nozzle blocked and the printer was printing air - just like my heel bone that has internal errors.

When you say clean up the model, what is the best way to do this. Back to Meshmixer?

Many thanks

MM

 

[valcrow 145]

You can try mesh mixer, I hear it can fix some of these problems but I don't have experience with it myself.

In Max, (or blender) or whatever modelling program you're using, I would unify the direction of the normals, and see if there are unwelded verticies in the center seam. And check for double faces. (faces that sit exactly ontop of each other occupying the same 'space'.

Then I would boolean the whole model together so that it's one watertight mesh. It looks like the supports inside of it aren't 'combined' together.

 

[medicalmodeller 5]

This model is not something that I have made. It is a model of a real boat and I asked the boat builders for a file with which to make a model. They sent me a file in .3dm format. I have had to convert it to .stl. So these errors have arisen somewhere in the translation

MM

 

[valcrow 145]

I think more likely they didn't build the model for 3D printing in mind.. Most animation software doesn't really care if it's watertight or interpenetrating. These issues only arise when you want to print them.

It doesn't look like a translation error to me because it has telltail signs of mirror and welded halves.

 

[gr5 2,210]

First of all never print anything without checking in layer view first. That would have made it more obvious. Also I recommend setting infill to 20% only if to check how it looks in layer view as that makes it more easy to see what is "inside" and "outside".

All the red areas in xray view are a problem but often you can ignore that and fix the model with one of the 11 possible combinations of "fix horrible" (never check both A and B - that leaves 11 combinations). If not then you can fix it in meshlab (which is free). Here are some hints:

http://meshlabstuff.blogspot.com/2009/04/how-to-remove-internal-faces-with.html

 

xray view shows white or shades of blue if a beam traveling from your eye passes through an even number of faces. If it passes through an odd number it ends up red. That implies either a hole or an extra face.