# How to get a small resampled plane slice given a point, a normal, and slice dimensions?
**URL:** https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138
**Category:** Development
**Created:** [December 18, 2020, 11:09pm UTC](https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138 "2020-12-18T23:09:56Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@mikebind](https://discourse.slicer.org/u/mikebind)
#### Post date: [December 18, 2020, 11:09pm UTC](https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138/1 "2020-12-18T23:09:57Z")
I would like to be able to get a resampled image slice as a numpy array by supplying a slice center (in RAS coord), slice dimensions and resolution (e.g. 50x50 pixels which are 1 mm x 1 mm), a slice normal vector, and a slice view-up vector. From looking at the Curved Planar Reformat module code, I was able to put together a function which will produce a reformatted volume where the slices of the straightened volume are almost what I want, except that it requires a curve as input (rather than just a point and vectors), does not allow control of the viewUp vector (I assume because it is calculated automatically from the curve?), and outputs a volume rather than a single image array.
What I want to be able to do is obviously exactly what is happening in slice viewers when in reformat mode, but I have not been able to find the code which actually does the resampling work based on the inputs, probably because I have trouble following C++ code around in the Slicer GitHub repository. I see things like vtkSlicerReformatLogic::SetSliceNormal() which seems related, but it’s more modifying the state of a continuously existing object (a slice node I think) than linking a specific set of inputs to a specific resampled image output slice, which is what I am trying to do.
Both of these examples (the Reformat and CurvedPlanarReformat modules) make it seem like what I want is probably already doable within Slicer without me trying to write code from scratch to do the resampling I want, but I could use some help figuring out how to use or modify the existing tools. Thanks for any help you can provide!
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [December 18, 2020, 11:46pm UTC](https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138/2 "2020-12-18T23:46:13Z")
You can use `SetSliceToRASByNTP` as a convenient way to set slice position by specifying normal and x axis direction and slice position. See example here: [https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Set\_slice\_position\_and\_orientation\_from\_a\_normal\_vector\_and\_position](https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Set_slice_position_and_orientation_from_a_normal_vector_and_position)
If you don’t want to use the slice viewer for this then you can create a single-slice volume with the desired dimensions, zero-centered, axis-aligned, then transform it to the desired position and orientation, and use it as a reference volume in an image resample module.
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### Author:  [@mikebind](https://discourse.slicer.org/u/mikebind)
#### Post date: [December 18, 2020, 11:52pm UTC](https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138/3 "2020-12-18T23:52:44Z")
Thanks, I think this will work fine for my purposes. I’ll take over the Red slice node, temporarily set the background volume to the volume I want to resample, use SetSliceToRASByNTP to orient the slice, and then grab the image array from the slice (which I see there is also code for in the script repository). Is there a way to control the pixel size of the extracted slice? It’s great if there is, but if not, I can just resample the 2D image to the desired resolution.
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### Author:  [@pieper](https://discourse.slicer.org/u/pieper)
#### Post date: [December 19, 2020, 12:01am UTC](https://discourse.slicer.org/t/how-to-get-a-small-resampled-plane-slice-given-a-point-a-normal-and-slice-dimensions/15138/4 "2020-12-19T00:01:58Z")
I had an example lying around that extracts randomly oriented samples from a volume. It shows how to set the dimensions and orientation. It’s no in the script repository.
> **[Documentation/Nightly/ScriptRepository - Slicer Wiki](https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Extract_randomly_oriented_slabs_of_given_shape_from_a_volume)**