FAQ and Troubleshooting

FAQ & Troubleshooting

Common questions and fixes. If your issue isn't here, please open an issue.

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Installation & launch

The app doesn't open on Windows

Almost always a missing native DLL. Windows self-contained WPF apps do not bundle their native DLLs into the .exe; the following must sit in the same folder as it:

wpfgfx_cor3.dll   PresentationNative_cor3.dll   D3DCompiler_47_cor3.dll
PenImc_cor3.dll   vcruntime140_cor3.dll         assimp.dll

Symptom: the process appears as Suspended in Task Manager, no window opens, and the Windows Event Log shows a DllNotFoundException.

Fix: re-extract the full portable ZIP (don't move the .exe out on its own), or use the installer, which places every file correctly.

macOS says "the developer cannot be verified"

Alpha builds are ad-hoc signed, not notarized. Right-click the app → Open → Open to tell Gatekeeper to trust it. You only do this once per download. (Double-clicking will keep showing the warning — you must use right-click → Open the first time.)

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Importing models

My .obj loads but has no texture / wrong colors

The .obj references its material and images via a .mtl file. Make sure the .mtl and the texture image files are next to the .obj and named as the .obj/.mtl expect. Missing textures fall back to a flat color.

A .pdo won't import

Only Pepakura Designer v3 files are supported. Files from other/newer Pepakura versions, or password-locked .pdo files, may fail to parse.

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Unfolding

Some pieces are red / flagged as overlapping

Red means two faces of a piece overlap in 2D, so it can't be cut as one flat piece. To fix:

1. Run Auto-Arrange, which also tries to reduce overlaps by repositioning.
2. Cut an edge inside the offending piece to split it into two smaller pieces.
3. Manually drag pieces apart into empty page space.

Highly curved or closed shapes will always need several cuts — that's expected for papercraft.

The unfolded model is way too big or too small

Set the real-world target size in the Setup dialog shown right after you press Unfold (e.g. target height in mm). You can re-unfold to apply a new size.

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Export & printing

My printed model is the wrong size

Print at 100% / "Actual size", never "Fit to page" or "Scale to fit" — those resize the pattern and break the millimetre scale. In the print dialog, set scale to 100% and disable any auto-fit option. Print one test page and measure a known edge against the on-screen dimension to confirm before printing the whole model.

SVG vs PDF — which should I use?

• PDF — print directly; page-accurate. Best for home printing.
• SVG — vector; best if you'll edit in Illustrator/Inkscape or feed a cutting machine (Cricut, Silhouette, laser cutter).

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Projects

Can I open a Windows .4hu on macOS (or vice-versa)?

Yes. The .4hu bundle (mesh + textures + overrides + piece positions + groups) is cross-platform between the Windows and macOS builds.