Tips? Eliminating Deflate Artifacts when Hollowing model with boolean

[artmaker]

Hi,

To prepare 3d prints I hollow out my models using the Boolean subtract process (thank you 4R8!), but I am having issues with deflating the inner boolean subtract mesh. Lots of artifacts appear when parts of the mesh invert. Extreme example photo attached.

Does anyone have tips to avoid or remove deflation artifacts WITHOUT adding to the volume of the inner subtraction mesh? Or another hollowing workflow?
Ive tried:

• Smoothing the problem areas
• Low-res remeshing Both of these methods can stop or remove the artifacts, but they add volume to the mesh in various places. This creates areas of thinner than nominal wall thickness, which I can’t easily see or fix until after I’ve uploaded it for print (60 mins+).
• Digging out the offending features prior to deflation. Having areas with thicker than nominal walls is fine.
  This works (sort of) with various brushes, but looks really sloppy inside unless I also smooth, which adds thins the resulting walls.
  Am I using the wrong brush or brush setting? Something that digs/removes smoothly or a smooth brush / setting that never adds any mesh “height?”

I’m often 3d printing right at the minimum wall thickness and having print models rejected for thin wall areas is a time consuming process.

Any pointers out there?
I would really appreciate it!

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[marcus_civis]

Instead of using deflate you might consider using a duplicate mesh and scaling it. With DynaMesh and Decimation Master you can simplify the mesh as much as you want, simply cutting off features that would end up too thin, such as the ears. I know that scaling along the different axes is not as good as the deflation method but it does avoid the clean up problems you describe.

If you fill the inner mesh with white, assign a color to the outer mesh and have Transparent on you can easily see which parts need adjustment. Then turn off Transparent so you can see the Live Boolean and use a cube set to subtract to give a cross-section. With the Gizmo you can move the cube to see the thickness at any point on your model, adjusting as necessary.

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[artmaker]

Thanks
Yes, scaling would be a artifact free, but the wall thickness would be too non-uniform.

Any thoughts on a good workflow for for eliminating things like ears, eyelids, sharp corners that will create artifacts with Deflate? Is there a tool that works like a ball end mill? Or a good way to delete the resulting artifacts after deflation and prior to the boolean operation?
Like I mentioned, smoothing and remeshing does the job artifact-wise, but can raise the surface of the inner mesh. I only want to “lower” surfaces. I’m working with really thin walls.

I love your Tip of viewing the model thickness by moving a boolean subtracting cube.

Any ideas are appreciated!

Scaling makes wall thickness non-uniform (back of neck, hair, chin)

Deflate yields uniform wall thickness except where the inner mesh is smoothed or where there are deflation artifacts.

Thanks for the wall thickness previewing tip using a boolean subtraction cube. I will use this.

[MentalFrog]

Use Meshmixer; http://www.meshmixer.com/

There is a way to do it in Zbrush but it takes extra steps and there are still some problem areas with certain models/features. I hope Pixologic puts in a proper hollowing process. 3D printing is a big thing and hollowing models is a major part of the printing process. Until then use Meshmixer. It does a great job and it’s still currently free.

[artmaker]

@MentalFrog – Thanks! I just downloaded Meshmixer. Nice.
The hollowing tool seems pretty good.
Yes, Z brush does needs some better tools for 3d printing.

[artmaker]

After using meshmixer some, unless I am doing something wrong, it’s not going to work.
The hollowing tool / thickness creation feature – at least when making thin walls – is not uniform and can result in zero thickness areas and some weird topology.
And I haven’t figured out how to keep my original model resolution and topology.

Does anyone know if these are just limitations of the free Meshmixer program?

Thank you