How to make a hollow box with thin walls (Shell) in SolidWorks?

Short Answer

Yes — in SolidWorks, the fastest and most common way to make a hollow box with thin walls is to model a solid box first, then apply the Shell feature to remove one face and define a uniform wall thickness. This works best on clean, simple geometry. Very thin values can fail on small fillets or tight corners.

What You Need to Know Before

Warning: Shell often fails when the requested wall thickness is larger than nearby internal radii, small faces, or narrow gaps in the model. A box with fillets, drafted faces, or extra cuts can shell unpredictably if the thickness creates self-intersecting geometry.

How to Make a Hollow Box with Thin Walls in SolidWorks

• Command: Shell

• Shortcut: No default keyboard shortcut

• Quick Steps:

  1. Create a solid box first, typically with Features > Extruded Boss/Base from a rectangular sketch.
  2. Go to the Features tab on the CommandManager and click Shell.
  3. In the Shell PropertyManager, select the face to remove, enter the wall Thickness, optionally enable Shell outward, then click OK.

Variables & Settings

• Key Setting: Thickness

• Expert Setting: Thickness controls the wall offset from the original solid faces. For most box models, keep the thickness smaller than any small detail radius or edge condition. Use Shell outward only when the external size must grow instead of reducing the internal cavity.

Why it Fails

• Cause 1 (Geometry): The wall thickness is too large for the model’s corners, fillets, or narrow regions, causing offset faces to intersect.
• Cause 2 (layers/Locks): The selected face may belong to imported or problematic geometry with bad faces, gaps, or corrupted topology, especially in non-native files.
• Cause 3 (Command/Logic): Shell was applied after complex features like fillets, cuts, ribs, or drafts, making the offset operation less stable than shelling the simpler base solid first.

Quick Fix & Best Practice

• Quick Fix: Suppress fillets or small detail features, apply Shell to the simple box first, then rebuild and add fillets afterward.
• Manager’s Verdict: Use Shell for standard plastic enclosures, covers, and simple hollow parts. Avoid relying on it late in the feature tree when the model already contains small details or complex geometry.

FAQ

Can I shell a box without removing a face?
Yes, leave all faces unselected in the Shell command to create a closed hollow body.

Should I shell before or after fillets?
Before fillets is usually more reliable and easier to rebuild.

Can I make different wall thicknesses with Shell?
Yes, by using the Multi-thickness Faces option when needed.

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