# Whether to consider adding a reference chart tool to the left of the 3D view

**URL:** <https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970>\
**Category:** Development\
**Tags:** python\
**Created:** [June 6, 2021, 6:34am UTC](https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970 "2021-06-06T06:34:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![slicer365](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/slicer365/32/67549_2.png) [@slicer365](https://discourse.slicer.org/u/slicer365)\
**Post date:** [June 6, 2021, 6:34am UTC](https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970/1 "2021-06-06T06:34:05Z")

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For some projections or orthogonal views, I think it is very helpful to add a grid reference. Is there a script to achieve this effect?

 ![捕获](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/e/4eb6659504afc29ad1bc1e1d6e084b37f951fc82.jpeg)

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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:** [June 6, 2021, 7:05pm UTC](https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970/2 "2021-06-06T19:05:18Z")

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There are many ways to achieve this. Can you explain what your end goal is?

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**Author:** ![slicer365](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/slicer365/32/67549_2.png) [@slicer365](https://discourse.slicer.org/u/slicer365)\
**Post date:** [June 7, 2021, 3:29am UTC](https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970/3 "2021-06-07T03:29:56Z")

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If I want to use scissor tool to fill a cylinder, then I need to determine an axis, or a circle center, and then use this point as the starting point of the scissor.In addition, sometimes I need to register two models，Of course, there are many methods, but I can use the reference grid to translate.If I need to hollow a baffle, similar to this picture, then I can use scissor for circular cutting, but without a grid reference, the distribution of these holes will be irregular.  
 ![捕获](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/5/e5c754c560f5446dd57665696e93fd8b77f3e111.jpeg)

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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:** [June 7, 2021, 4:17am UTC](https://discourse.slicer.org/t/whether-to-consider-adding-a-reference-chart-tool-to-the-left-of-the-3d-view/17970/4 "2021-06-07T04:17:39Z")

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You can generate a set of cylinders (vtkCylinderSource), append them into a single polydata (vtkAppendPolyData), then add that to a model (`slicer.modules.models.logic().AddModel()`). You can then either combine it with a segmentation in Segment Editor (import the model and use logical operators effect) or subtract using Combine models module (in Sandbox extension).