Intersection Check

Finds and shows every place where solid groups and components overlap. Overlaps can be very expensive if you only find them in production.

Group: Inspect
Works on: Solids in your selection, or in the whole model if nothing is selected, including nested ones. Groups that aren't solid are skipped.
Changes the model?: No. It only marks the overlaps on screen.
Needs: SketchUp Pro (it uses SketchUp's Solid Tools). Full version.

How to use it

Make the parts solid first: only solids are checked.
Click Intersection Check. On large models this takes a while; SketchUp's status bar (bottom left) shows the progress.
Read the counter: Solids Intersections (overlaps found), Solids (how many were checked) and Open Edges (edges that stop other groups from being solid).
To see the overlapping parts better, turn on Hide Non Intersecting Solids.
To leave the view, choose another tool, for example Select.

Before and after

The table and chairs, all magenta, with 49 solids and no problems left in Analyse — **Before:** 49 solids, all repaired.

Intersection Check on the same model: red marks at the chair joints; the counter shows 16 intersections, 49 solids and 0 open edges — **After:** 16 intersections, marked in red where the chair parts overlap.

Close-up of overlapping rods with the intersecting volumes marked in red; the counter shows 17 intersections — A close-up: each overlap is outlined in red.

Limitations and intentional geometry

Non-solid groups are ignored, not reported as overlaps. Check the Open Edges number: if it isn't 0, some groups weren't checked. Run Analyse to find them.
Parts that only touch are not overlaps.
Some overlaps are intended, for example a pin pressed into a hole, or parts you will join into one. Decide for each one; SuSolid only shows them.

Check the result

After you move or trim the overlapping parts (SketchUp Pro's Tools › Solid Tools can subtract one from the other), run Intersection Check again. The Solids Intersections count should be 0, or only the overlaps you meant to keep.