Renderer Bounds

Screenshots

Why?

KSP's craft size calculations use axis aligned bounding boxes around each part. This isn't a problem, since only the axis aligned dimensions are counted.

Except that's not true. The bounding box that counts in world coordinates is around the bounding box of the part in its own local coordinates, so if you rotate a part 45 degrees then its world dimensions will increase by 41% even if the part is a cylinder.

Except that's still not true. The part's bounding box is calculated from the bounds of each mesh, and each mesh can have its own rotation transform. So a cylinder mesh that's been rotated 45 degrees will increase the part's dimension by 41%, then if you rotate the part 45 degrees that compounds another 41%, for a total of +100% to the size of the part.

I created this mod because I was tired of 1.25m tanks making my craft 1.8-2.5m wide, so they wouldn't fit in my 2x2m LC, among many other less straightforward failure modes.

Why else?

An ordinary mesh gets its box from its own vertices, so rotation is its only problem. A skinned mesh with joints and animations does not. Its bounding box is stored in the model file and used as is, regardless of the mesh pose. Some parts measure too small when deployed. Some read too large when undeployed. Some are always wrong, and some of those wildly so.

With Renderer Bounds, a part's dimensions will always match its current pose. Some examples from a survey of a large RP-1 install, unrotated and stowed, largest dimension unless noted:

Some solar panels have baked in bounds tens to thousands of meters too large:

In a few cases, like the extended BFS solar panel, Renderer Bounds accurately reports a larger size than the stock box.