# Discordance 3D data after processing

**URL:** <https://community.pix4d.com/t/discordance-3d-data-after-processing/20768>\
**Category:** PIX4Dcatch\
**Created:** [December 10, 2021, 4:09pm UTC](https://community.pix4d.com/t/discordance-3d-data-after-processing/20768 "2021-12-10T16:09:51Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![kevin.sun-sothi](https://avatars.discourse-cdn.com/v4/letter/k/cab0a1/32.png) [@kevin.sun-sothi](https://community.pix4d.com/u/kevin.sun-sothi)\
**Post date:** [December 10, 2021, 4:09pm UTC](https://community.pix4d.com/t/discordance-3d-data-after-processing/20768/1 "2021-12-10T16:09:51Z")

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Hello,

I use the pix4d Catch solution with the Vidoc antenna for the acquisition of my pictures. Then, I use pix4dmapper to process them and get the 3D model.

Sometimes, the model output from pix4dMapper is distorted (see picture) and I don’t understand the reason. Is it a problem during the acquisition or the processing? And how can I correct it?

Thank you very much

 ![nuagedepointdecale](https://global.discourse-cdn.com/pix4d/original/2X/e/ec5630e69866d376f3bc3ade2d9c905d3179b6f1.jpeg)

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**Author:** ![Mike\_K](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/mike_k/32/4697_2.png) [@Mike\_K](https://community.pix4d.com/u/Mike_K)\
**Post date:** [December 10, 2021, 8:18pm UTC](https://community.pix4d.com/t/discordance-3d-data-after-processing/20768/2 "2021-12-10T20:18:22Z")

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Hi Kevin,  
Without the quality report it is difficult to fully troubleshoot your project. You can upload here or feel free to open a support case and we can go over it with you. However, we have found that image acquisition can play a vital role in the quality of the output. We suggest using your mobile device as though you were a drone capturing a conventional photogrammetry project. Essentially you will want to make a very smooth path along your project area. If a drone is flying a grid or circular pattern it is not making abrupt changes in its flight pattern. You will want to do the same. These abrupt changes will cause issues and make your final outputs unusable.

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**Author:** ![socafl](https://avatars.discourse-cdn.com/v4/letter/s/46a35a/32.png) [@socafl](https://community.pix4d.com/u/socafl)\
**Post date:** [January 31, 2022, 7:44am UTC](https://community.pix4d.com/t/discordance-3d-data-after-processing/20768/3 "2022-01-31T07:44:56Z")

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Bonjour je ne sais pas si la raison est la même mais j’ai des discordances quand je fais des allers-retours pour filmer une tranchée. Au retour il y a une différence en altitude. Pouvez-vous me donner une solution. Si je ne fais que l’aller, la tranchée n’est pas très réaliste.  
De plus j’ai relevé un bâtiment et sur les 10 M j’ai une erreur finale de 10 cm.  
je travaille avec un Galaxy A52 sans lidar.

Cordialement,

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**Author:** ![Mike\_K](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/mike_k/32/4697_2.png) [@Mike\_K](https://community.pix4d.com/u/Mike_K)\
**Post date:** [January 31, 2022, 3:57pm UTC](https://community.pix4d.com/t/discordance-3d-data-after-processing/20768/4 "2022-01-31T15:57:51Z")

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Hi socafl,  
It is quite possible that you are experiencing the same problem. I suggest making your passes along the trench as smooth as possible. Try not to make any abrupt changes as this can induce error into your model. Along these lines, when you are capturing around a building you will want to do the same. If you do not then the error will grow larger as you move around the building.