Added plugin hologram (#1296)

* Added plugin hologram

Author: MarkSlat

_plugins/hologram.md

@@ -0,0 +1,79 @@
+---
+layout: plugin
+
+id: hologram
+title: OctoPrint-Hologram
+description: A simple OctoPrint plugin to display a render based on the preloaded G-code.
+authors:
+- MarkSlat
+license: AGPLv3
+
+date: 2024-05-17
+
+homepage: https://github.com/MarkSlat/OctoPrint-Hologram
+source: https://github.com/MarkSlat/OctoPrint-Hologram
+archive: https://github.com/MarkSlat/OctoPrint-Hologram/archive/main.zip
+
+tags:
+- ui
+- Gcode
+- visualizer
+
+screenshots:
+- url: /assets/img/plugins/hologram/demo.jpeg
+  alt: Example preview of Benchy
+  caption: Example preview of Benchy
+- url: /assets/img/plugins/hologram/setup_1.gif
+  alt: Example setup step 1
+  caption: Example setup step 1
+- url: /assets/img/plugins/hologram/setup_2.gif
+  alt: Example setup step 2
+  caption: Example setup step 2
+
+
+featuredimage: /assets/img/plugins/hologram/demo.jpeg
+
+
+compatibility:
+  octoprint:
+  - 1.4.0
+  os:
+  - linux
+  - windows
+  - macos
+  python: ">=3.7,<4"
+
+---
+This plugin allows a user to an accurate preview of their print projected onto the build plate. Designed for cameras mounted on the build plates.
+
+## Example Usage
+Generate a render by loading the print file, clicking the render button and it overlays a render onto the build plate.
+
+![demo](/assets/img/plugins/hologram/demo.jpeg)
+
+## Setup
+In the settings page, enter the physical X and Y dimensions of the build plate (not the print volume).
+
+Position the box over the build plate and secure it to initiate the calibration process.
+
+![setup_1](/assets/img/plugins/hologram/setup_1.gif)
+
+Make any necessary adjustments. Ensure the arrow points towards the origin.
+
+![setup_2](/assets/img/plugins/hologram/setup_2.gif)
+
+Navigate to the hologram tab and select a file to render and preview
+
+## Raspberry Pi
+Since this plugin depends on Numpy you many have to run the following.
+- sudo apt-get install libopenblas-base
+- sudo ldconfig
+
+See: https://numpy.org/devdocs/user/troubleshooting-importerror.html
+
+## Future plans
+To automatically detect failures and defects in real-time by cross comparing the rendered model with the actual print, layer by layer. If a certain confidence level is met, the print will be paused. Check the pre-releases for more information.
+
+## Acknowledgments
+I would like to give credit Yaqi Zhang’s for using their script for part of the Gcode rendering function.
+https://github.com/zhangyaqi1989/Gcode-Reader