We've built an extension called Preflight and we're looking for experienced SketchUp users to beta test it.

It's for models you've inherited rather than built: files pieced together by several people, by a team of juniors, or handed over by a client. Preflight scans the whole model, shows you what's wrong, and then applies modeling best practices to clean it up.

The video below walks through one full run on a real client model, a 3,700-definition site model with 33 scenes. The cleanup took just under an hour, and the saved file came out at about half its original size.

What it fixes

Materials

• merges duplicate materials, but never materials whose render settings differ, so V-Ray materials that only look alike in SketchUp stay separate
• moves container materials onto the faces that actually show them
• strips container materials nothing inherits
• paints visible back faces to match their fronts
• clears opaque back materials facing into closed solids, and fills the bare back of a transparent face with its front material
• removes materials painted onto edges
• converts placed images into textured faces, so they can be resampled, exported and picked up by a renderer
• purges materials nothing uses

Textures

• resamples oversized textures and re-encodes them to cut file bloat, keeping transparency where an image has it
• finds materials whose images look the same and gives them all the best version of the picture, while each keeps its own size and render settings
• can export every texture to one folder and relink the model to it

Geometry

• merges coplanar faces, but only where the material, tag and texture mapping match on both sides
• removes stray and zero-length edges
• removes faces sitting exactly on another face
• turns reversed faces the right way round, including solids that are inside out
• can soften and smooth shallow edges
• can erase hidden faces and groups (never hidden edges, which usually hold a surface together)

Structure

• deletes empty groups and components
• collapses wrapper groups that hold a single child, handing their tag down to it
• purges unused definitions
• folds identical groups into one shared component, keeping each copy's own scale and material, or only folding copies that match if you prefer
• bakes instance scale into the geometry and squares up flipped or swapped axes

Tags

• clears tags on geometry that repeat the tag of the container it sits in
• moves a tag shared by everything in a container up onto the container
• purges tags nothing uses
• can move loose edges and faces onto one tag, Untagged by default

Styles

• removes styles no scene uses
• merges styles with identical settings

How it works

1. Choose what runs in the settings window. Any fix that can change how the model renders is marked, and each one can be unticked.
2. Scan. This reads the model and changes nothing.
3. Review the results, grouped by kind. You can step through each problem on screen, one object at a time.
4. Apply. It repeats until a pass finds nothing left to do.
5. Read the summary and the before-and-after report, which is saved beside the model.

Anything that needs a human decision is listed in the report rather than changed, and you can walk through those items the same way.

Preflight never saves your model. If you don't like the result, close without saving and the file is exactly as it was.

There are also two quick fixes, Merge coplanar faces and Erase stray edges, that work on the selection or the group you're editing. You can bind them to keys in Preferences > Shortcuts.

It runs on Mac and Windows, in SketchUp 2021 and later.

You can request a beta license here:
https://www.terminalagency.com/preflight

We'd most like to hear how it does on your messiest models: what it got right, what it missed, and anything it did that you didn't expect. Feedback here or by email are both welcome.

preflight-screencapture.mp4