Box with rounded corners (inside and out)


Hi –

I am creating a box with rounded corners. I’ve found the RoundCorner plugin and it’s been very helpful creating the outside corners of my box. The challenge I’m having is maintaining the desired wall width with the desired radius on the corners.

I have a box 40x40x40 (the actual size does not matter) with 2mm width walls and bottom (top is open). I need an 8mm radius on all bottom and side edges of the box.

When using RoundCorner, I would need to have walls over 6mm wide in order to accommodate rounded outside corners due to square inside corners. Is there a way to get rounded corners on the inside of the box that run parallel to the outside faces to maintain the desired corner radius and wall width?


Instead of using Round Corner, why not just draw the cross section and use Follow Me?


I haven’t used Follow Me before (yet?). I’ve seen and read about it and I think I get the concept. How would it handle the compound corners where the bottom edges and side edges meet?


Give it a try. Draw a square and round the corners with the 2-Point Arc tool and draw the profile as I showed. Select the path, get the follow Me tool, click the profile.


Success! Thanks for that pointer.

However…I am getting ‘holes’ (inside and out) in the bottom corners where the bottom edges meet the sides.


Work at a larger scale or use The Dave Method. You could just model with units set to meters while you think in millimeters.


Thanks, I’ll give that a try.


Success…really this time! I think I had a harder time finding the model after scaling it from m to mm than I did learning Follow Me.

Thanks for the input and guidance.


Good. Now you need to reverse the faces. White faces out, blue back faces to the inside. If that’s for 3D printing you don’t need to scale it down to millimeters after you’re done. Just export the STL and when you import it into the slicer set the units as mm.


You can mark Dave’s first post as the answer so that others can find it more quickly.


Interesting…I guess I wasn’t aware of the faces. I’m a novice with Sketchup…primarily creating simple, square models…so this function has not really come into play.

I am developing models for 3D printing. Using this example, I did correct the faces and did sample prints. In this case, there didn’t seem to be any differences in export or output. I have installed and will start using the Solid Inspector extension to make use I don’t have any issues going forward.

Thanks again for the assistance and guidance.


The thing about face orientation, at least with most slicer software, is that it tells the printer which side of the face the materials is on and which side should be air.