Aligning dimensions to rotationally off axis objects

I am working on a project in Sketchup 15 (16 still won’t work with El Capitan properly). The interior I am working on is in a building where no two walls are parallel and corners are rarely right angled. So huge quantities of the drawing are ‘off axis’ rotationally.

Once you leave the main drawing axes Sketchup can get quite difficult especially for referencing and snapping. I have developed strategies for this, but now I have reached the final dimensioning stage, I am running into difficulties.

I will try to explain my problem with a very over simplified example. The top figure in the attached screen shots show a 100 x 50 x 30 mm block. It is rotated off axis. When you use the dimension tool two possibilities occur. The tool snaps to the drawing axes or the tool snaps to the model’s axes. The danger being that the former produces dimensions that do not reflect true side lengths. In a model this simple with the axes visible the problem is trivial and easy to see and correct. However when the rotation relative to drawing axes is very small and the axes themselves are not necessarily visible in that portion of the drawing it is easy to get caught out and find you have inaccurate dimensions by reason of misalignment.

Another problem is shown in the second screenshot. In this case the vertical dimension is off axis relative to the rear horizontal edge of the model. Try as I may I cannot get this dimension to snap to anything except the drawing axis. It is nonetheless accurate because the verticals in the object are on axis so the problem is less severe. But it would be much more readable and clear if the vertical dimension aligned to the models rear horizontal edge so that its arrowhead touched the arrowhead of the width dimension. Once again it’s clear enough in a simple drawing like this but on more complex objects with lots of dimensions this misalignment can get very scruffy and confusing.

So the simple question at the end of this long winded preamble is quite simply:

In cases where the model axes and drawing axes are very close but not identical, is there any way to force Sketchup to align its dimensions to the model and ignore the drawing axes?

It’s always the simple things that are the most frustrating ……………:confused:

Here’s one way: Make the object you want to dimension into a Component. Open the Component for edit, right-click on a face, and choose “Align Axes”. This will set the drawing axes parallel to the face while the component is open for edit. Now draw the dimensions inside the open component. They will naturally align with the current (temporary) drawing axes. You can either leave them inside the component or cut, close the component, and paste-in-place if you’d like them outside.

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To be more precise, if you use the 2 point method, it creates dimensions that by default are aligned with the axis of the current editing context.

So if you are inside a rotated group or component, the dimension will be aligned with the local axis.

BUT,… pay attention to the status bar help text whilst in tools.

You can instead use a selection method, ie hover over the edge to be dimensioned, and the dimension will be be aligned with the edge, even if the edge is rotated. (But you may need to be within the same entities context to use the selection method built into the DimensionTool.)

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You need to try be patient, and let the inference engine catch up to your mouse movements.

If you pull the dimension away from the edge and it snaps to one of the axis, just move it in a arc until it snaps away and the inference engine should then try the closest alignment to one of the object’s edges.

EDIT: Actually, I do see that the axis snaps seem to be much more powerful, if the origin is one of the dimension line anchors. Ie, the closer to the origin the more powerful the axis snaps.

Also the inference engine will also snap to other dimension’s extension lines, if both dimensions are in the same edit context, But again I experience the same reluctance to align off axis close to the origin.

BTW, a dimension object like most others, can be rotated after creation.

  1. Preselect the vertical dimension.

  2. Activate the RotateTool.

  3. Hover over the bottom vertex of the vertical edge that is being dimensioned.

  4. Press and drag the cursor up along the blue (Z) axis so you get a Blue rotate around Z axis inference lock. (Release the mouse pick button when the protractor locks to the blue axis.)

  5. Move the cursor out along the green axis until you get an “On Green Axis” inference, and click. This is the base of the angle of rotation.

  6. Move the cursor over onto the horizontal edge that you wish the dimension to aligned to, until you get an “On Edge” inference, and then click to complete the rotation.

Admirably clear thanks. I like this it’s very simple and easy to apply.

Well … I hope so … it looks it writing … I’ll need to wait till tomorrow to find out. Late here now. :slight_smile:

In answer to this first reply. I got the first part completely … the second I need to try hands on tomorrow to fully understand.

Re. your second answer: Rotation of existing dimensions had never occurred to me. I had no idea it was possible. A great ‘fix’ if I don’t get on with your first suggestions … Thanks again Dan.

Another tidbit, I had the style set to X-Ray mode, so I could click the green axis inside the solid, and then the far horizontal edge, still inside the object.

Hi Slbaumgartner and Dan.

Problem definitely solved. Making a group or component and then opening it to dimension it in the context of the model works a treat and has the great advantage of being wonderfully simple. I don’t even bother to move the dimensions outside. I just assign them their own layer so I can view with or without as needed.

X Ray mode is a really neat trick. Not just in this case but in other cases as well. Dimensioning often needs hidden points to be accessed causing a mass of awkward orbiting to see them. X Ray avoids all that!

Thank you both.

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I have the 2018 Sketchup. I have the same problem when dimensioning the model that is askew of the axis. I’ve tried making the model a group or component. I don’t have a “Align Axes”. Dimensions are not perpendicular to model and not accurate. Thanks, Bob

Can you upload and example file that gives you trouble?

You will only see that on the context-click (right-click) menu when the component is open for edit and you right-click on one of its faces. Yet another way is to temporarily place the “drawing axes” aligned with the way you want the dimensions to align. Remember to reset the axes after you finish.



The file seems to large to send even when sent in a zip file. Bob

Maybe copy out the element that you’re having problems with and paste it into a new file that you can upload.


I tried to load a partial model, but the file is always too large. This is a snapshot of the model. The main model feature is drawn to the standard axis. This part of the model is off angle. I’ve tried making it a group, component and resetting the axis to this part of the model, but the dimension lines continue to move off the true angle and measurement. The measurement on the left side, for some reason, kept to a straight line. Thanks, Bob

Try purging unused stuff from Window>Model Info>Statistics and try the upload again.

Sketchup Model Island Test (93.5 KB)

Thanks for the tip on the purge. It seemed to work. Bob

OK. I see what you’re getting. One way to deal with it is to open the component for editing and then add the dimensions.

An alternative would be to draw lines outside the component for the lengths you need to dimension and select those edges. Personally I’d do the dimensions in LayOut instead.

Out of curiosity, why are the component axes inverted and positioned where they are?

I tried dimensions while editing the component and that didn’t work. The
inverted axis is a mistake. Thanks,

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