# Calculating Object Points for Aruco Board

**URL:** <https://forum.opencv.org/t/calculating-object-points-for-aruco-board/4771>\
**Category:** Python\
**Tags:** calib3d, aruco\
**Created:** [August 15, 2021, 9:51am UTC](https://forum.opencv.org/t/calculating-object-points-for-aruco-board/4771 "2021-08-15T09:51:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Alpheron](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/alpheron/32/2918_2.png) [@Alpheron](https://forum.opencv.org/u/Alpheron)\
**Post date:** [August 15, 2021, 9:51am UTC](https://forum.opencv.org/t/calculating-object-points-for-aruco-board/4771/1 "2021-08-15T09:51:21Z")

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So I was trying to track a cube with an Aruco marker on all faces and wanted to find out the cub’s absolute position in space. In order to track the cube, I would need to create an Aruco Board and I wanted to now how I get the object points of all the markers. Is there a scale of reference or a specific unit involved on how to do that? I have been looking at the documentation: [OpenCV: cv::aruco::Board Class Reference](https://docs.opencv.org/master/d4/db2/classcv_1_1aruco_1_1Board.html#details)  
and I have also been looking at [Three-Dimensional Aruco Boards | Peter F. Klemperer (peterklemperer.com)](http://www.peterklemperer.com/blog/2017/11/30/three-dimensional-aruco-boards/) and they seem to define a cubic Aruco board with points. Is there a particular method to get the values of those points. For reference, I have calibrated the camera and have those values ready. Can someone help on how to proceed?