Hey there! I’ve tinkered with this in MeshLab plenty of times, so let me break down the two most straightforward ways to modify your mesh’s bounding box:

Method 1: Precise Scaling via Transform Tool #

This is perfect when you know the exact dimensions you want your bounding box to be:

• Open your mesh in MeshLab, then head to the top menu and click Filters.
• Hover over Normals, Curvatures and Orientation, then select Transform: Scale.
• In the pop-up dialog, you’ll see your mesh’s current bounding box dimensions listed at the top. Enter your desired X, Y, and Z values in the Target BBox fields below.

  Here’s a snapshot of this dialog for reference:
  

• If you want your mesh to stay centered within the new bounding box, make sure the Center on BBox checkbox is ticked.
• Click Apply—your mesh will resize automatically to fit the new bounding box.

Method 2: Direct Bounding Box Resize Filter #

This purpose-built filter offers more alignment flexibility:

• Go to Filters > Mesh Filtering > Bounding Box Resize.
• The filter panel will appear on the right side of the screen. Here, you can:
  • Enter exact Width, Height, and Depth values for your target bounding box.
  • Use the Scale Factor to proportionally resize the box (e.g., a factor of 1.5 will increase all dimensions by 50%).
  • Choose how your mesh aligns with the new box using the Alignment dropdown—options include centering, aligning to the bottom-left corner, and more.
• Once you’ve set your preferences, click Apply to update the bounding box.

Quick Pro Tip #

If you only need to adjust one axis (like making the Z-axis taller without changing X/Y), just enter the original X and Y values into the target fields, plus your desired Z value. This keeps the other dimensions unchanged while resizing the one you need.

内容的提问来源于stack exchange，提问作者Ab17