# Fiducial markers hidden when cropping ROI disabled, and shown when cropping ROI enabled

**URL:** <https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665>\
**Category:** Support\
**Tags:** gui, roi\
**Created:** [March 24, 2022, 5:13am UTC](https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665 "2022-03-24T05:13:31Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![DIV](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/div/32/12816_2.png) [@DIV](https://discourse.slicer.org/u/DIV)\
**Post date:** [March 24, 2022, 5:13am UTC](https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665/1 "2022-03-24T05:13:31Z")

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I created a fiducial maker that was located just outside a cropping ROI.

- When cropping ROI is enabled and displayed, the external fiducial marker isn’t shown (_this is logical_).
- When cropping ROI is enabled but not displayed, the external fiducial marker is shown (_this is **not** logical_).
- When cropping ROI is not enabled and not displayed, the external fiducial marker is shown (_this is logical_).
- When cropping ROI is not enabled but is displayed, the external fiducial marker isn’t shown (_this is **not** logical_).

This occurs in version 4.13.0-2022-01-19 of Slicer.  
Display of the 3D volume is tied to enabling of the cropping ROI, not display of the cropping ROI (_that is logical_).

—DIV

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/c/b/cb8b719135e2467f50b6e58058b5bbc5727fa334.png)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/5/759c251945c71a15684491392c019a67484f944c.png)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/8/68d08ca841ce4af0828f795709d5ae46f5c83e17.png)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/b/d/bd00b1eb09575dcb7c88bad546a218ce884a792b.png)

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<div class="post-metadata">

**Author:** ![DIV](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/div/32/12816_2.png) [@DIV](https://discourse.slicer.org/u/DIV)\
**Post date:** [March 24, 2022, 5:19am UTC](https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665/2 "2022-03-24T05:19:46Z")

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Sorry, I have mischaracterised the problem.  
It is not due to external location of the marker. When the marker is far outside, it can be seen always.  
Rather, it seems to be due to unfortunate conflict between the marker and the light-grey handles at the corners of the cropping ROI, or (similarly) the coloured handles in the centre of the faces of the cropping ROI.  
So, it’s still unexpected/undesirable behaviour, although the actual behaviour/mechanism is different to how I initially interpreted it.  
—DIV

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/1/81fa48f774c4971ae5128de02c11adf295108664.png)

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [March 24, 2022, 1:03pm UTC](https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665/3 "2022-03-24T13:03:53Z")

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Markups control point labels are only displayed for visible points. Visibility is determined only for the centerpoint position, not for the entire point glyph, therefore, as you noted, a line can occlude a point. It would be computationally too expensive to check visibility of all (or many) points of a glyph, so it is not likely that we will change this behavior.

If you must always see the labels then you can enable `Occluded visibility` (in Markups module → Display → Advanced → 3D display section).

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<div class="post-metadata">

**Author:** ![DIV](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/div/32/12816_2.png) [@DIV](https://discourse.slicer.org/u/DIV)\
**Post date:** [March 24, 2022, 1:20pm UTC](https://discourse.slicer.org/t/fiducial-markers-hidden-when-cropping-roi-disabled-and-shown-when-cropping-roi-enabled/22665/4 "2022-03-24T13:20:38Z")

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Thanks. Actually, I didn’t notice the ROI box line occluding the markups, only the ‘handles’ on the ROI box.

As you guessed, retaining the label would be sufficient to avoid the main cause of confusion for me.