# Symmetric scissor effect issue

**URL:** <https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210>\
**Category:** Support\
**Created:** [October 12, 2017, 12:30pm UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210 "2017-10-12T12:30:13Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![hherhold](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/hherhold/32/12199_2.png) [@hherhold](https://discourse.slicer.org/u/hherhold)\
**Post date:** [October 12, 2017, 12:30pm UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210/1 "2017-10-12T12:30:13Z")

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The size range in the scissor slice cut symmetric effect is specified in mm, but the number appears to be the number of slices. If I pick 20mm, regardless of the range in my data set, it will do +/- 10 slices from where I draw my scissor region.

This is in a recent nightly build.

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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:** [October 12, 2017, 2:28pm UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210/2 "2017-10-12T14:28:22Z")

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I confirm that it is in slices. Could you please enter a bug report at [issues.slicer.org](http://issues.slicer.org)? If you could submit a pull request with the fix then it would be even better.

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**Author:** ![hherhold](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/hherhold/32/12199_2.png) [@hherhold](https://discourse.slicer.org/u/hherhold)\
**Post date:** [October 12, 2017, 11:20pm UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210/3 "2017-10-12T23:20:02Z")

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I’ll try fixing it - might have a couple of questions along the way. I know C/C++ and a little python, but I’m very new at the innards of slicer.

Thanks!

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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:** [October 13, 2017, 2:47am UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210/4 "2017-10-13T02:47:03Z")

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I had a look and the issue and it was simple enough so I went ahead and [fixed it](https://github.com/Slicer/Slicer/commit/16719ef6cfc45e881db5e661ba766499a8a60f28). It’ll be available in the nightly release on Saturday.

Thank you for reporting the issue and offering your help to fix it!

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**Author:** ![hherhold](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/hherhold/32/12199_2.png) [@hherhold](https://discourse.slicer.org/u/hherhold)\
**Post date:** [October 13, 2017, 12:18pm UTC](https://discourse.slicer.org/t/symmetric-scissor-effect-issue/1210/5 "2017-10-13T12:18:04Z")

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Wow, thank you!

I’d gotten as far as figuring out how much I didn’t know (which was extensive, to say the least), so reading through your fix will be a very useful tutorial for me.

Thanks again!