Something doesn't compute with follow me?

I am creating a bowl. I am using an arc from another model. It is welded one piece.
I create a base circle and attach the arc to it.
I create a form to do a follow me (the sail).
I copy the sail and scale a mirror image.
I attach it to the other end of the circle diameter.
result =

notice the top distance = 133600.000000mm
I delete the 2nd sail and do a follow me and get this.

notice the diameter of the top = 133600.000153mm

Why is the follow me result not 133600.000000mm???

Attach the model.

Having tested you sizes I see no issues that aren’t user related.
As you haven’t specified how many segments in your circle I’m guessing it is quite a few. So have you actually attached your dimension to the corresponding vertex.
Here’s a quick image showing 6 decimal places on a follow me.

1 Like

As Box said, attach the model. As SketchUp circles are not geometrically correct but consist of segments, the result varies according to the points you measure across. There would be a difference between measuring between two vertices or between two edges…

BTW, why does it matter? The error is way smaller than any manufacturing tolerances (1.5 /10 000 of a millimeter in a circle 133.6 METERS across)

1 Like

I don’t know what good it will do you as the issue isn’t apparent in the final model unless you have the progression to it. But have at it. The object next to the follow me is the previous part that didn’t have the right size. I copied the arc from it.

The final result I am after is a bowl that has a top outside diameter of 136000 and top inside diameter of 133600. The inside must be exact to mate with the top. The outsides of the top and bottom will overlap when assembled so hopefully an intersect will connect them. I tried to get them exact but that didn’t work. I am also having an issue with the intersect - when I do it to the whole model, parts of it don’t get the message. The proverbial 10%.

Bottom inside.skp (1.9 MB)

I measured on the green axis so I wouldn’t have that issue.
there are 120 segments.
Your model has straight sides. mine are curved.
Apparently it matters when I try to connect the top and bottom, I am getting a lot of broken piece. It isn’t a tolerance issue. I am trying to print this whole thing in one piece, not post assemble them. The slicer is having the issue. I did manage to get the previous one printed, so I have no idea why this one is having an issue as I used the same top and bottom.

I ran it with a circle and an arc program gened and got the same dimensions, so there is something strange with the parts I am using. I guess.
Maybe I have been struggling with this tooooo long.
need some eye work.
back to research

THANK YOU ALL - I managed to figure it out with your help.
It was all in the bottom. I actually built it totally different.
I redid it using 4 circles, 2 lines, 2x 2 point arcs, 2 more lines and some erasure, and a follow me and more erasures. perfect purple.
then married it to the top.
and got this

All that cyan will make it print hollow.
Now all I have to do is to marry in the internal structure.
That will be tedious.

This topic was automatically closed 91 days after the last reply. New replies are no longer allowed.