Extruded 2x4 Has Strange Sliver On Both Ends

I’m making some facia boards and I do this by creating a rectangle and extruding it out to the thickness of 1.5". It’s a 2x4 currently but I’ve seen this on other dimensions too.

The first time I saw this, I nuked the component and started again. This seemed to have worked that time, but now I can’t seem to make this entity without the sliver. What’s odd is that the thin volume is present on one side of the board (left in this picture), but also on the left on the other side of the board. So it’s like the board is a not a perfect rectangular prism (each side has a long wedge).

What am I doing wrong?

Looks like you have modeled it off axis. It would be easier to tell you what’s going on for sure if you share the .skp file.

Dang, apologies… I should have examined the situation more closely. Turns out two of my rafters were very slightly offset. When I drew the rectangle from end rafter to end rafter, the resulting rectangle was not on the plane… if went back slightly so when I extruded it, it wasn’t perfectly square. Not sure how those two rafters got pushed back, but I’m a newb so anything is possible…

After I fixed the two rafters, the facia board is correct. off axis indeed. Thanks again @DaveR.

Still learning best practices here. I’m used to working in Illustrator or diagrams.net, doing mostly 2D, so this 3D stuff is throwing me for a loop. I need to slow down and be more careful.

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One thing to keep in mind is that the bounding box for a component or group will, by default, be aligned with the model axes. So when your geometry is off axis the bounding box won’t fit it tightly. That’s more obvious when geometry is drawn a lot off axis as in the case of my rafter example.

If you need some sort of report of the dimensions of components from your model, the orientation of the bounding boxes will be important. My rafter is 12 feet long but you can see the only dimension that makes any sense is the thickness (shown as Height by the ancient old plugin I used to display those dimensions.)

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