How to Determine the Angle of a Line Relative to the SU Axis

Is there a way to determine the angle of a line / edge relative to one of the SU axis. I need that function to check some bad geometry in my model

Hello, in the style panel you can color your edges by axis in the edit tab. It’s not quite what you are looking for but it will allow you to spot edges that aren’t along desired axis

You can also use the protractor tool to measure the angle.

To determine the angle you need a protractor and a plane for the protractor.

Simple method:

  • drag a guide from axis towards edge’s endpoint (the one that needs to be measured)

  • draw an edge on top of that guide

  • close in a triangular face between the two edges to obtain a face.

  • with the protractor inference “On Face” you can now measure the exact angle between both edges, thus the angle between edge and axis.

(See pink perimeter around the face.)


Thanks for the suggestions so far. However, I forgot to mention that the angle of difference is sub degree/millimetre.

You might need to change the display precision for angles in Model Info>Units.
Screenshot - 7_23_2022 , 8_39_18 AM

If you know it’s very slightly off, it might be easiest to rotate it farther off axis and then rotate it back to on axis.

Thanks Dave
I will do what you suggested Ie rotate then rotate to the correct angle. That is why I am trying to find out which elements are just out of alignment with the axis.
All of my models are to do with buildings and I have the display precision set to the highest level possible. I am assuming that is the correct setting?
Also I read, a long time ago, that Colour by Axis, is not real precise Ie picking up items that are just out of alignment?

Usually SketchUp makes it easier to see/feel inaccurate lines than software like AutoCAD. If two edges aren’t perpendicular push-pull won’t work as it should, if two edges don’t connect it won’t generate faces, stray edges might do the same effect. It’s accurate enough that you don’t need to bother with such a precision. I have mine set to the tenth of the millimeter and in architecture that’s more accurate than what can actually be built. Why would you want more?

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Thanks for your input.
I hear what you say about construction accuracies. The only reason that I set SU precision is to pick up alignment problems.

The precision settings are only about what is displayed, it has no affect on the actual precision of the model. The main reason to set precision to a finer setting is to help spot errors. When it is coarser sketchup shows rounded figures which may hide small errors. It’s not unknown for people to come with a model where two obviously different sizes are showing the same amount, this is due to rounding from a too coarse setting.
For example.
And yes you are correct, the colour by axis is out enough that it misses tiny errors, errors often introduced by having Length Snapping enabled in units, turn that off for all your templates. Also watch for a tilde in your dimensions, another sign something is amiss.

Thank you Box
Your information is very helpful.
I guess that I need to model a bit slower and be more careful.