Dimension Errors

I had a very embarrassing encounter this morning in which one of my drawings came back with an error pointed out to me: the radius’ of the pieces drawn did not align (and unfortunately, had already been manufactured).

When I referred to the Rhino file to find the error, I discovered that despite the fact that the two vectors did not in fact align, they still showed the same radius when dimensioned! Hence why it wasn’t clearly apparent the first time.

Is this a bug or is my brain still on vacation? This isn’t the first time I’ve had issues with dimensions / vectors being inaccurate in Rhino 6 (did not have this issue with v5).

The first photo shows the two pieces to be manufactured separately and dimensioned; the second, one piece over the other w/ dims again to illustrate the issue.

Hello - what does the radius command say about these? Are they in parallel planes? And if so are the planes parallel to the CPlane as the dimensions are added?

Can you post or send us the file at tech@mcneel.com? Please include a link back to this conversation in your comments.


The radius command gives the same number. The curves are all planar. Here’s the line work.

dim error.3dm (636.0 KB)

Hello - the curves have the same radius but are oriented differently - here is one moved on top of the other, end point to end point.

The lower part, in your image, the wider one, is not tangent, at the center, with it’s opposite.


Hm. I can see they are not tangent, but I don’t understand why. If they are the same radius, shouldn’t they overlap completely still?

Hi Chris - one is tipped, slightly, compared to the other. If you rotate it on its end point at the middle by that difference, they correspond as you expect.


In which axis? I can’t seem to see it.

Okay, I seem to have identified the discrepancy. Now to retrace my steps and figure out how I got to this point.
Thank you, Pascal, for your help and quick responses!

Also, just to be clear on the solution: the lines were not disoriented or out of axis; rather, since they are both mirrored objects, the one had somehow been shortened before being mirrored (so that if you zoomed in closely, you could see the shorter of the two pairs actually made a bit of a ‘V’). This explains why radius’ were the same.