Fill a hollow solid

[saeppi]

Hello,
I've got a GL32 screw cap which is open on both ends. I need to fill the space in between so I can use the new solid in a Boolean operation (cutting another solid with this filled screw cap). Is there way to do this in FreeCAD?


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OS: macOS 10.14
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16117 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.2)
Hash: dbb4cc6415bac848a294f03b80f65e888d531742
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

[openBrain]

There are many ways. But basically depend on where your object comes from. STEP file, mesh, Part or PartDesign, ...
Could you please attach the model as it is currently ?

[saeppi]

Hi openBrain,
of course: GL fill.FCStd

[chrisb]

I performed a checkGeometry with BOPCheck enabled and I'm afraid you will not get very far with this: It took very long at 100% CPU and finally came up with lots of errors (BOPAlgo_GeomAbs_C0, and BOPAlgo_InvalidCurveOnSurface).

[openBrain]

OK, as the G32 shape looks like a "skin" (an open shell actually), here is what I did to get a solid.

1. Using Defeaturing Workbench, create the 2 missing faces by selecting the appropriate edges
2. Select the original shape + the 2 created faces and use Draft Upgrade to get a shell
3. Use Draft Upgrade a second time on the shell to get a solid

I performed a checkGeometry with BOPCheck enabled and I'm afraid you will not get very far with this: It took very long at 100% CPU and finally came up with lots of errors (BOPAlgo_GeomAbs_C0, and BOPAlgo_InvalidCurveOnSurface).

Also see the check was highly loading the CPU, and finally canceled it. However I checked the above method making a boolean cut in the obtained solid, end everything seems OK.

[chrisb]

I was successful as well by using the shell to slice a cylinder of appropriate size Radius=20, Height=17,9.
I cannot upload it here, because the file grows to 1.7 MB.

[openBrain]

File light enough to be forum compatible. Find attached.

[chrisb]

If I make a simple copy from the slice the filesize drops to 88KB too. Here the price for keeping it parametric is approximately doubling the size.

[TheMarkster]

One issue you might run into when you make an internal thread by cutting a solid using the external thread as a cutting tool is you won't have any tolerance. They'll both be the same size, making for a really tight fit, perhaps too tight. Consider scaling the cutting tool to some slightly larger size, but only in x and y directions.

[saeppi]

Thanks all, that did the job very well!
(Had to create a simple copy in order to use it in a Boolean operation, though)