Center of a square/rectangle face

Sorry for this offensively simple question :stuck_out_tongue: , but I seem to be unable to find the center point of squares and rectangles faces. Note that Im doing this solely with the move tool, I could use Tape tool somehow but it interferes with me moving the objects, anyhow.
Circles are fine, the mouse snaps to the center face just like I would expect it to.
So in short, why isn’t my mouse snapping to square or rectangle centers?

I googled and couldnt find my question asked. Most seem to be about square in a square or how to draw the rectangle from a center point.

The inference engine remembers the last few points you focus on. Hover over the midpoint of one edge (blue circle). Then move to hover over the midpoint of an adjacent edge. Then move to the center of the rectangle, the two inference lines will appear referencing the previous midpoints and snap to the object center.

I can find the both lines from the edges blue points, red and green lines in this case. But there is no exact center point to grab on to.
So what Im about to do is put a larger square on top of a smaller square, with both being centers aligned so to say.

You might try using four sided polygons, at least for squares.

Yes that works. A bit fiddly to work with since I have to rotate and reshape the polygon to match the expected rectangle dimensions, and it doesnt solve rectangle. But it’s something

Modifier key with rectangle tool draws from center.

The center of the large square has to have the same center as the tiny square

You can also use two construction lines drawn from corner to opposite corner. The meeting point will be the centre.

Or you can use the Midpoint extension. I use it all the time.

Yeah I know about the diagonal Tape lines, it requires a little more work for me but its doable.
Slower, I mean compared to just finding the center point how I hoped Sketchup would do it.

I found a midpoint extension that I managed to install.
Now I can work with my rectangles and squares just with the freedom I need.


You might consider just using the offset tool for this. You select the square, and then offset it to create a larger square around it. Perfectly centered.

I guess there may be a small argument in favour of having a tool or extension that finds the centroid of a “closed” element. By that I mean either a 2D object that has one surface and no edges other than the bounding ones, or a 3D object that Solid Inspector would call solid.

In my today’s knowledge I can see, it is not well coded at all and implementation is a bit awkward :blush:… But there is such a thing as an alternative Line tool:

Maybe one day I’ll rewrite …

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Here’s one way that doesn’t need extra lines or guides to be drawn.

It would be nice if there was a center of mass inference point. Here’s a page that shows the arithmetic involved (this includes irregular polygons, not just rectangles):

I wrote a Center-of-Gravity [CofG] extension some time ago - it works on ‘solids’ and assumes the same density for each ‘part’…
There’s also a separate CofG ‘reporter’…

Note - you can also combine different density materials’ CofGs to get a combined CofG result…

I must be confused about the goal, this sounds easy with native inferencing, no guides or center points necessary? Drawing a rectangle centered on another, use rectangle tool and press modifier toggle key to draw rectangle from center, inference midpoint of two adjacent sides, snap to center, draw.

Or to move one rectangle into another, grab by the center with inference and move to center with inference.


There are lots of solutions here but if one rereads the OP, the main question is why there is no centrepoint to a square/rectangle like there is with a circle. I seem to remember that there used not to be one for circles either but it was added a few years ago (and very necessary it was too!).

I guess the answer is that you can’t expect to have a default centrepoint for every polygonal shape. It exists for a circle because it is a common shape and there is no other quick and easy way to determine it.

:wink: :innocent:
Just for fun…
Non square rect with center.skp (10.7 KB)

How have you done that? I don’t get a tooltip that reads Center, though I can find the centre with offsets from line centres.