'Display Only Axis Aligned' is Misleading

The recently added feature Display Only Axis Aligned on ‘Image’ objects is rather misleading. Enabling this boolean does not disable the image from perspective and orthographic views (as the term ‘only’ would imply), but simply enables it in that view.

  • Add new object of type Image (or drag image from file browser into 3D viewport)
  • In the properties menu, click on the image properties tab, as seen below:

Rename Display Only Axis Aligned to Display Axis Aligned, and update tooltip to remove the word “Only”.

EDIT 9/18/2019
This suggestion was based on a misunderstanding of the feature. As per the discussion in the comments below, my revised solution would be to rename Display Only Axis Aligned to Display Only View Axis Aligned to aleviate confusion from the fact that the nondescript term “axis” often refers to a world axis throughout the UI.

Hi @bblanimation,

the feature is hiding an image if the view ( doesn’t matter if ortho or perspective) is not axis aligned. Does it in your case behave differently?

Ah, I see the behavior is different than I thought. My confusion was due to the fact that when “Display Only Axis Aligned” is checked immediately after adding the image, the display is not updated until the viewport is moved. Take the following steps to see what I mean:

  • from the 3D viewport of freshly opened default file, create a new Image object, and select any PNG image from your files (the file extension may not matter, but for consistency sake this is the extension I used).
  • Do not rotate or change the 3D viewport perspective in any way (as this would trigger an update and nullify the issue)
  • Open the image properties, and check ‘Display Only Axis Aligned’.

You should see that the image does not disappear, despite the viewport perspective not being aligned. This behavior may confuse users (as it did me) and I believe it should be fixed before release.

Do you have the rotation values of your image axis aligned? If you add a new image its aligned to the current viewplane. And then it will not fade. I could not reproduce it otherwise.

It is checking against the axis of the viewplane !!! Maybe that’s why you find it confusing

I’ve recorded my screen below as I follow the described steps; perhaps you can tell me if I’m misunderstanding something:

Yes that is no bug. It’s intended. Two things happen here.

  1. If you add that image it is aligned to the current view direction.
  2. When your “display only axis align” checkbox is activated blender decides if the image shall be drawn based on a comparison of the alignment of the two orientation axis, the viewplane axis and the image axis.

So in the moment after creation both things come together. You added it aligned to the view axes
And as because of that view axes and image axes are aligned, the comparison described in the second statement above is true.

It could have been also programmed to compare the view axes with the world axes. That way images would just be drawn if the camera is aligned to the world axes. That might be the case you’d expect.

The current implementation is more flexible, as it generally allows to have other orientation axes than the world axes as reference orientation, but without snapping to such an orientation system just hard to get visible again.

Anyhow in the common case this system is used for images that are aligned to the world axes. So you would have your image rotation e.g. have set to 90degree on x and the rest to zero degree.

Here is an example, why it’s more flexible. You can align the camera to an arbitrary rotation of your choice. In my case 45 degree on all three axes. You just have to set the image to that angle and it would work.

But when I say its more flexible. It does not mean that its really that useful to be able to do that. At least for me. Some may disagree.

Thank you for your help @Debuk! This makes much more sense now. I assumed, when I saw “axis aligned”, that it was referring to the world axes. Perhaps it would be helpful to change the bool name to Display Only View Axis Aligned? I see now that the tooltip clarifies view axis, but I think this should be clearer from a glance.

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