Oddities in dimensioning and inferencing in SU2017



I’ve found a couple of oddities in the way Dimensioning works in SU.
1 The location of Diameter dimensions jump in a recent model.
To dimension a hole diameter, one has to be in the context of the hole. I dimension the circle at the top of the hole, pull it out a bit from the circle, and click to position it away from the circle.

When I close the component, which is nested two deep, the dimension text jumps back to the very edge of the hole. Like this:
Component open to place dimension:

Close the component:

It’s doing in on all the circle/hole diameters in this model, both old and new ones.
Cam lock jig dimensioned.skp (199.1 KB).

It doesn’t do this in a simple new drawing, at least not in architectural units, and not even when nested two deep as in this model.

Also, a copy of this model with the dimensions deleted, and textures added, when imported into another model, seems to have something I can’t detect that is showing the component bounding box much larger than the actual sub components it contains - and all the axes are at corners in the model or subcomponents.

Sample cam lock joint.skp (160.1 KB)
When I change scenes in the dimensioned model, the model goes very small, then snaps back to the right size when the animation stops. I wonder if this is a variant of the weird behaviour I experienced with text and reported a couple of days ago? I wonder if there may be an unattached dimension somewhere, invisible and not selectable?

2 Linear dimensions won’t inference to a node in a circle.
i can hover the mouse over any part of the circle, and can’t start a dimension there.
This may be by design - it WILL inference to the circle centre. But seems odd.


Scale the component definition and the dimensions will correct themselves.

If you are changing the size of a component using the scale tool, either open it for editing and scale the geometry within or use Scale Definition in the Context menu. Failure to correct the definition’s scale also has an impact on the appearance of textures.


I’ll try that when I get home later this afternoon.

I don’t recall scaling any of the main components, though I did mirror some of the holes.

It’s behaving the same on mirrored and unmirrored holes.


Perhaps you started modeling it in meters? The definition comes into SketchUp at 200 metres long. You can see that forself if you drag in a copy of the component from the Components window.


Ah, that must be it - I did for some other models I’ve just been working on, but not, I thought, this one. Faulty recollection, if this one comes in so big!

I’ll use Scale definition, and see if that fixes it.

LATER: yes, it does.

Why does this cause that behaviour?


I can duplicate the problem by adding a diameter dimension within a component and then scaling that component. The dimension jumps way out depending on whether the component is open for edit or not. I suspect that the offset vector for the dimension is being scaled as if it is in model coordinates not local coordinates of the ComponentDefinition. Seems like a bug!


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