STL Hollow Tool — Hollow Out Models & Save Resin Community
Questions, answers and tips from people who use the STL Hollow Tool — Hollow Out Models & Save Resin. Hollow an STL with a set wall thickness and a drain hole, see resin saved.
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This page shows only real posts from real people, so it starts empty. The guide below has the questions people most often have about the STL Hollow Tool — Hollow Out Models & Save Resin. Pick one to start a thread, or write your own.
From the tool guide: common questions about STL Hollow Tool — Hollow Out Models & Save Resin
The items below are not posts by community members. They come from the written guide for this tool and are here to get a conversation started. Use “Ask a follow-up” to open a thread about any of them.
Is the cavity wall thickness exact?
It is exact on flat faces and at convex corners; on very sharp concave details the offset can overlap, which the check reports.
From the tool guide Ask a follow-upDo I still need a drain hole in my slicer?
If you tick the drain hole here no, otherwise yes. Resin slicers also have hole tools.
From the tool guide Ask a follow-upWhat happens to the original file?
Nothing — your file is not modified or uploaded; you download a new file.
From the tool guide Ask a follow-upDoes it work for FDM?
It works, but FDM slicers hollow with infill, which is usually better.
From the tool guide Ask a follow-upWhat this tool does
Resin is expensive, and a solid miniature or bust wastes most of it in the interior. Hollowing creates an inner cavity so only a shell of your chosen thickness is printed. This tool builds the cavity by offsetting the surface inwards: each vertex moves along a normal computed from its neighbouring faces so that corners keep a uniform wall thickness, and the cavity is added as an inside-out inner shell. You choose the wall thickness (0.4–8 mm) and see volume and resin cost before and after.
How to use it, step by step
- Drop in a watertight STL.
- Choose wall thickness and drain-hole size.
- Press Hollow and inspect with the section tool.
- Download the hollow STL and slice it.
Tips from the guide
- Use 1.5–2.5 mm walls for miniatures, 2–4 mm for functional parts.
- Always add at least one drain hole; add a second small vent at the top to avoid suction.
- Features thinner than twice the wall thickness cannot be hollowed — the check will flag them.
- FDM slicers hollow with infill settings; this tool is for closed-cavity resin prints.
Common mistakes to avoid
- Printing a hollow part without a drain hole.
- Choosing a wall thicker than thin features.
- Hollowing a non-watertight mesh.
Who uses it
- Resin printer owners. Save resin on miniatures and busts.
- Anyone printing large solid blocks. Reduce weight and print time.
- Educators. Demonstrate shell vs solid volume.
How to ask a question people can answer
A good thread on the STL Hollow Tool — Hollow Out Models & Save Resin saves everyone time. Start with a title that names the exact problem, such as the input you used, the result you expected and the result you got. A title like “Not working” is hard to answer, while a title with the specifics gets replies quickly.
- Say what you tried. List the steps you followed and any settings you changed, so replies do not repeat what you already did.
- Share a small example. A short sample input and the output you saw is worth more than a long description. Remove anything private first.
- Mention your setup. Your device, browser and whether you are on a phone or a computer can explain many odd results.
- One question per thread. Separate topics get clearer answers and are easier to find later with the search box above.
- Come back and reply. If a suggestion worked, say so and upvote it, and if you found the fix yourself, post it for the next person.
Community rules
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